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  • Question 1 - A 55-year-old male presents with fever, night sweats, weight loss, and upper abdominal...

    Incorrect

    • A 55-year-old male presents with fever, night sweats, weight loss, and upper abdominal pain. Upon examination, his liver and spleen are enlarged. A complete blood count shows elevated levels of basophils, eosinophils, and neutrophils. What is the most probable cause of these symptoms?

      Your Answer: KRAS

      Correct Answer: BCR-ABL

      Explanation:

      The symptoms displayed by this individual suggest the presence of chronic myeloid leukemia (CML), which is identified by the Philadelphia chromosome. This chromosome results from a genetic abnormality where chromosome 9 and 22 exchange genetic material, leading to the formation of the BCR-ABL gene.

      Understanding Chronic Myeloid Leukaemia and its Management

      Chronic myeloid leukaemia (CML) is a type of cancer that affects the blood and bone marrow. It is characterized by the presence of the Philadelphia chromosome in more than 95% of patients. This chromosome is formed due to a translocation between chromosomes 9 and 22, resulting in the fusion of the ABL proto-oncogene and the BCR gene. The resulting BCR-ABL gene produces a fusion protein that has excessive tyrosine kinase activity.

      CML typically affects individuals between the ages of 60-70 years and presents with symptoms such as anaemia, weight loss, sweating, and splenomegaly. The condition is also associated with an increase in granulocytes at different stages of maturation and thrombocytosis. In some cases, CML may undergo blast transformation, leading to acute myeloid leukaemia (AML) or acute lymphoblastic leukaemia (ALL).

      The management of CML involves various treatment options, including imatinib, which is considered the first-line treatment. Imatinib is an inhibitor of the tyrosine kinase associated with the BCR-ABL defect and has a very high response rate in chronic phase CML. Other treatment options include hydroxyurea, interferon-alpha, and allogenic bone marrow transplant. With proper management, individuals with CML can lead a normal life.

    • This question is part of the following fields:

      • Haematology And Oncology
      25.4
      Seconds
  • Question 2 - A neonatal hearing screening program screened 10,000 newborns by measuring otoacoustic emissions (OAE)....

    Correct

    • A neonatal hearing screening program screened 10,000 newborns by measuring otoacoustic emissions (OAE). Out of these, 200 newborns failed the screening test and were invited for a test of brainstem auditory evoked potential (BAEP), which is considered the gold standard for diagnosing hearing impairment in newborns. Among these 200 newborns, 100 were confirmed to have hearing impairment by BAEP. What is the correct statement regarding this scenario?

      Your Answer: The accuracy of the screening test cannot be determined

      Explanation:

      Limitations of Screening Test Results

      In the study, 200 out of 10,000 subjects were found to have hearing impairment through a screening test. However, for the 9,800 subjects who tested negative, no further testing was conducted to confirm if they truly did not have hearing impairment. This means that we cannot determine the accuracy of the screening test from the data provided, nor can we calculate the sensitivity, specificity, or negative predictive values. The only value that can be calculated is the positive predictive value, which is 50%. It is important to note the limitations of screening test results and the need for further testing to confirm diagnoses.

    • This question is part of the following fields:

      • Clinical Sciences
      60.2
      Seconds
  • Question 3 - Ms. Johnson is a 35-year-old asthmatic woman with severe community acquired pneumonia. She...

    Correct

    • Ms. Johnson is a 35-year-old asthmatic woman with severe community acquired pneumonia. She has been admitted to the intensive care unit for cardiovascular support. Currently, her blood pressure is 80/64 mmHg, heart rate is 128 bpm, and cardiac output is 3.2 L/min. Ms. Johnson is receiving 15 L/min of oxygen through a facemask and has oxygen saturations of 88% with a respiratory rate of 16. Her temperature is 39.6°C. What is the estimated stroke volume for Ms. Johnson?

      Your Answer: 25 ml

      Explanation:

      Cardiac Output and its Relationship to Health Conditions

      Cardiac output is the product of heart rate and stroke volume. Stroke volume can be calculated by dividing cardiac output by heart rate. The average cardiac output is 5 liters per minute, with a normal stroke volume ranging from 50-85 milliliters per beat, depending on heart rate.

      When a person experiences poor oxygen saturation and a normal respiratory rate, it may indicate that they are becoming exhausted and unable to breathe rapidly. This, combined with low blood pressure, tachycardia, and a failure to maintain cardiac output, can be indicative of shock. Additionally, a high temperature may suggest severe sepsis secondary to pneumonia.

      cardiac output and its relationship to various health conditions can help medical professionals diagnose and treat patients more effectively. By monitoring heart rate, stroke volume, and other vital signs, healthcare providers can identify potential issues and intervene before they become life-threatening. Proper management of cardiac output is crucial for maintaining overall health and preventing serious complications.

    • This question is part of the following fields:

      • Clinical Sciences
      47.1
      Seconds
  • Question 4 - A parent brings their toddler to the Emergency Department after noticing a pale...

    Incorrect

    • A parent brings their toddler to the Emergency Department after noticing a pale yellow fluid leaking from their umbilicus. The doctor explains that this is due to the incomplete closure of a remnant from embryological development. What is the name of this remnant, which used to be part of the umbilical ligament?

      Your Answer: Allantois

      Correct Answer: Urachus

      Explanation:

      The allantois leaves behind the urachus, while the male prostatic utricle is a vestige of the vagina. The ductus arteriosus is represented by the ligamentum arteriosum, which links the aorta to the pulmonary trunk during fetal development. The ligamentum venosum, on the other hand, is the residual structure of the ductus venous, which diverts blood from the left umbilical vein to the placenta, bypassing the liver.

      During cardiovascular embryology, the heart undergoes significant development and differentiation. At around 14 days gestation, the heart consists of primitive structures such as the truncus arteriosus, bulbus cordis, primitive atria, and primitive ventricle. These structures give rise to various parts of the heart, including the ascending aorta and pulmonary trunk, right ventricle, left and right atria, and majority of the left ventricle. The division of the truncus arteriosus is triggered by neural crest cell migration from the pharyngeal arches, and any issues with this migration can lead to congenital heart defects such as transposition of the great arteries or tetralogy of Fallot. Other structures derived from the primitive heart include the coronary sinus, superior vena cava, fossa ovalis, and various ligaments such as the ligamentum arteriosum and ligamentum venosum. The allantois gives rise to the urachus, while the umbilical artery becomes the medial umbilical ligaments and the umbilical vein becomes the ligamentum teres hepatis inside the falciform ligament. Overall, cardiovascular embryology is a complex process that involves the differentiation and development of various structures that ultimately form the mature heart.

    • This question is part of the following fields:

      • Cardiovascular System
      11.2
      Seconds
  • Question 5 - A 25-year-old fitness enthusiast visits his doctor to inquire about the effectiveness of...

    Correct

    • A 25-year-old fitness enthusiast visits his doctor to inquire about the effectiveness of arachidonic acid supplements in promoting muscle growth. He is a gym trainer and participates in national bodybuilding competitions. He has been researching the benefits of arachidonic acid supplementation in increasing lean body mass, strength, and endurance. He asks his doctor to provide more information about arachidonic acid and whether there is enough scientific evidence to support its use.

      The doctor explains that arachidonic acid is a polyunsaturated omega-6 fatty acid that is produced from phospholipase. Can you identify the enzyme that catalyzes the conversion of phospholipase to arachidonic acid?

      Your Answer: Phospholipase A2

      Explanation:

      Phospholipase A2 is responsible for the transformation of phospholipids into arachidonic acid.

      The conversion of lecithin to lysolecithin is facilitated by Phospholipase A1.

      Leukotrienes are produced from arachidonic acid through the action of Lipoxygenase.

      Protein kinase is an enzyme that adds phosphate groups to other proteins through a chemical process known as phosphorylation.

      Phospholipase plays a crucial role in the production of phosphatidic acid.

      Arachidonic Acid Metabolism: The Role of Leukotrienes and Endoperoxides

      Arachidonic acid is a fatty acid that plays a crucial role in the body’s inflammatory response. The metabolism of arachidonic acid involves the production of various compounds, including leukotrienes and endoperoxides. Leukotrienes are produced by leukocytes and can cause constriction of the lungs. LTB4 is produced before leukocytes arrive, while the rest of the leukotrienes (A, C, D, and E) cause lung constriction.

      Endoperoxides, on the other hand, are produced by the cyclooxygenase enzyme and can lead to the formation of thromboxane and prostacyclin. Thromboxane is associated with platelet aggregation and vasoconstriction, which can lead to thrombosis. Prostacyclin, on the other hand, has the opposite effect and can cause vasodilation and inhibit platelet aggregation.

      Understanding the metabolism of arachidonic acid and the role of these compounds can help in the development of treatments for inflammatory conditions and cardiovascular diseases.

    • This question is part of the following fields:

      • General Principles
      17.4
      Seconds
  • Question 6 - A 32-year-old woman undergoes a colonoscopy and a biopsy reveals a malignant tumour...

    Incorrect

    • A 32-year-old woman undergoes a colonoscopy and a biopsy reveals a malignant tumour in her sigmoid colon. Her grandmother died of colorectal cancer at 30-years-old and her father developed endometrial cancer at 40-years-old. Which gene is suspected to be responsible for this condition?

      Your Answer: APC gene

      Correct Answer: Mismatch repair genes

      Explanation:

      The patient’s familial background indicates the possibility of Lynch syndrome, given that several of his close relatives developed cancer at a young age. This is supported by the fact that his family has a history of both colorectal cancer, which may indicate a defect in the APC gene, and endometrial cancer, which is also linked to Lynch syndrome. Lynch syndrome is associated with mutations in mismatch repair genes such as MSH2, MLH1, PMS2, and GTBP, which are responsible for identifying and repairing errors that occur during DNA replication, such as insertions and deletions of bases. Mutations in these genes can increase the risk of developing cancers such as colorectal, endometrial, and renal cancer.

      Colorectal cancer can be classified into three types: sporadic, hereditary non-polyposis colorectal carcinoma (HNPCC), and familial adenomatous polyposis (FAP). Sporadic colon cancer is believed to be caused by a series of genetic mutations, including allelic loss of the APC gene, activation of the K-ras oncogene, and deletion of p53 and DCC tumor suppressor genes. HNPCC, which is an autosomal dominant condition, is the most common form of inherited colon cancer. It is caused by mutations in genes involved in DNA mismatch repair, leading to microsatellite instability. The most common genes affected are MSH2 and MLH1. Patients with HNPCC are also at a higher risk of other cancers, such as endometrial cancer. The Amsterdam criteria are sometimes used to aid diagnosis of HNPCC. FAP is a rare autosomal dominant condition that leads to the formation of hundreds of polyps by the age of 30-40 years. It is caused by a mutation in the APC gene. Patients with FAP are also at risk of duodenal tumors. A variant of FAP called Gardner’s syndrome can also feature osteomas of the skull and mandible, retinal pigmentation, thyroid carcinoma, and epidermoid cysts on the skin. Genetic testing can be done to diagnose HNPCC and FAP, and patients with FAP generally have a total colectomy with ileo-anal pouch formation in their twenties.

    • This question is part of the following fields:

      • Gastrointestinal System
      10
      Seconds
  • Question 7 - A 32-year-old man is assaulted and stabbed in the upper abdomen. Upon arrival...

    Incorrect

    • A 32-year-old man is assaulted and stabbed in the upper abdomen. Upon arrival at the emergency department, he reports experiencing pain on the left side of his abdomen and has reduced breath sounds on the same side. Imaging studies reveal a diaphragmatic rupture. What is the level at which the inferior vena cava passes through the diaphragm?

      Your Answer: T12

      Correct Answer: T8

      Explanation:

      The diaphragm’s opening for the inferior vena cava is situated at T8 level, while the opening for the oesophagus is at T10 level.

      Anatomical Planes and Levels in the Human Body

      The human body can be divided into different planes and levels to aid in anatomical study and medical procedures. One such plane is the transpyloric plane, which runs horizontally through the body of L1 and intersects with various organs such as the pylorus of the stomach, left kidney hilum, and duodenojejunal flexure. Another way to identify planes is by using common level landmarks, such as the inferior mesenteric artery at L3 or the formation of the IVC at L5.

      In addition to planes and levels, there are also diaphragm apertures located at specific levels in the body. These include the vena cava at T8, the esophagus at T10, and the aortic hiatus at T12. By understanding these planes, levels, and apertures, medical professionals can better navigate the human body during procedures and accurately diagnose and treat various conditions.

    • This question is part of the following fields:

      • Neurological System
      12.4
      Seconds
  • Question 8 - A 40-year-old man is stabbed in the abdomen and the inferior vena cava...

    Correct

    • A 40-year-old man is stabbed in the abdomen and the inferior vena cava is injured. What is the typical number of functional valves found in this vessel?

      Your Answer: 0

      Explanation:

      Anatomy of the Inferior Vena Cava

      The inferior vena cava (IVC) originates from the fifth lumbar vertebrae and is formed by the merging of the left and right common iliac veins. It passes to the right of the midline and receives drainage from paired segmental lumbar veins throughout its length. The right gonadal vein empties directly into the cava, while the left gonadal vein usually empties into the left renal vein. The renal veins and hepatic veins are the next major veins that drain into the IVC. The IVC pierces the central tendon of the diaphragm at the level of T8 and empties into the right atrium of the heart.

      The IVC is related anteriorly to the small bowel, the first and third parts of the duodenum, the head of the pancreas, the liver and bile duct, the right common iliac artery, and the right gonadal artery. Posteriorly, it is related to the right renal artery, the right psoas muscle, the right sympathetic chain, and the coeliac ganglion.

      The IVC is divided into different levels based on the veins that drain into it. At the level of T8, it receives drainage from the hepatic vein and inferior phrenic vein before piercing the diaphragm. At the level of L1, it receives drainage from the suprarenal veins and renal vein. At the level of L2, it receives drainage from the gonadal vein, and at the level of L1-5, it receives drainage from the lumbar veins. Finally, at the level of L5, the common iliac vein merges to form the IVC.

    • This question is part of the following fields:

      • Cardiovascular System
      7.4
      Seconds
  • Question 9 - A 75-year-old man presents to the clinic with a chief complaint of dyspnea...

    Correct

    • A 75-year-old man presents to the clinic with a chief complaint of dyspnea while in a supine position. Despite having a normal ejection fraction, what could be a potential cause for his symptoms?

      Your Answer: He has diastolic dysfunction

      Explanation:

      When there is systolic dysfunction, the ejection fraction decreases as the stroke volume decreases. However, in cases of diastolic dysfunction, ejection fraction is not a reliable indicator as both stroke volume and end-diastolic volume may be reduced. Diastolic dysfunction occurs when the heart’s compliance is reduced.

      Cardiovascular physiology involves the study of the functions and processes of the heart and blood vessels. One important measure of heart function is the left ventricular ejection fraction, which is calculated by dividing the stroke volume (the amount of blood pumped out of the left ventricle with each heartbeat) by the end diastolic LV volume (the amount of blood in the left ventricle at the end of diastole) and multiplying by 100%. Another key measure is cardiac output, which is the amount of blood pumped by the heart per minute and is calculated by multiplying stroke volume by heart rate.

      Pulse pressure is another important measure of cardiovascular function, which is the difference between systolic pressure (the highest pressure in the arteries during a heartbeat) and diastolic pressure (the lowest pressure in the arteries between heartbeats). Factors that can increase pulse pressure include a less compliant aorta (which can occur with age) and increased stroke volume.

      Finally, systemic vascular resistance is a measure of the resistance to blood flow in the systemic circulation and is calculated by dividing mean arterial pressure (the average pressure in the arteries during a heartbeat) by cardiac output. Understanding these measures of cardiovascular function is important for diagnosing and treating cardiovascular diseases.

    • This question is part of the following fields:

      • Cardiovascular System
      22.9
      Seconds
  • Question 10 - A 25-year-old healthcare worker from Bangladesh, who migrated to the UK at the...

    Correct

    • A 25-year-old healthcare worker from Bangladesh, who migrated to the UK at the age of six, is undergoing an occupational health assessment that includes an interferon-gamma release assay (IGRA). The worker has no knowledge of their vaccination history and has never experienced symptoms of tuberculosis infection. What is the primary physiological function of the cytokine used in this diagnostic test?

      Your Answer: Activation of macrophages

      Explanation:

      Macrophage activation is triggered by interferon-γ.

      Interferon-γ is a cytokine produced by Th1 cells that promotes inflammation and activates macrophages. In medical testing, measuring the release of interferon-gamma by leukocytes in response to Mycobacterium tuberculosis antigens can indicate the presence of active or latent TB infection. This test is preferred over the tuberculin skin test as it does not yield a false positive result in individuals who have received the BCG vaccine.

      Macrophages produce cytokines such as interleukin-8 and tumor necrosis factor-α, which attract neutrophils to the site of infection.

      Eosinophil production is stimulated by interleukin-5, GM-CSF, and IL-3, which promote granulocyte maturation.

      Interferon-γ does not directly cause fever. Pyrogenic cytokines such as interleukin-1 and interleukin-6, produced by macrophages and Th2 cells, induce fever.

      Interferon-γ is a Th1 cytokine that promotes the differentiation of Th0 cells into Th1 cells, creating a positive feedback loop.

      Overview of Cytokines and Their Functions

      Cytokines are signaling molecules that play a crucial role in the immune system. Interleukins are a type of cytokine that are produced by various immune cells and have specific functions. IL-1, produced by macrophages, induces acute inflammation and fever. IL-2, produced by Th1 cells, stimulates the growth and differentiation of T cell responses. IL-3, produced by activated T helper cells, stimulates the differentiation and proliferation of myeloid progenitor cells. IL-4, produced by Th2 cells, stimulates the proliferation and differentiation of B cells. IL-5, also produced by Th2 cells, stimulates the production of eosinophils. IL-6, produced by macrophages and Th2 cells, stimulates the differentiation of B cells and induces fever. IL-8, produced by macrophages, promotes neutrophil chemotaxis. IL-10, produced by Th2 cells, inhibits Th1 cytokine production and is known as an anti-inflammatory cytokine. IL-12, produced by dendritic cells, macrophages, and B cells, activates NK cells and stimulates the differentiation of naive T cells into Th1 cells.

      In addition to interleukins, there are other cytokines with specific functions. Tumor necrosis factor-alpha, produced by macrophages, induces fever and promotes neutrophil chemotaxis. Interferon-gamma, produced by Th1 cells, activates macrophages. Understanding the functions of cytokines is important in developing treatments for various immune-related diseases.

    • This question is part of the following fields:

      • General Principles
      20.2
      Seconds
  • Question 11 - What is a true statement about the p53 gene? ...

    Incorrect

    • What is a true statement about the p53 gene?

      Your Answer: It is located on chromosome 13

      Correct Answer: Li-Fraumeni syndrome predisposes to the development of sarcomas

      Explanation:

      Understanding p53 and its Role in Cancer

      p53 is a gene that helps suppress tumours and is located on chromosome 17p. It is frequently mutated in breast, colon, and lung cancer. The gene is believed to be essential in regulating the cell cycle, preventing cells from entering the S phase until DNA has been checked and repaired. Additionally, p53 may play a crucial role in apoptosis, the process of programmed cell death.

      Li-Fraumeni syndrome is a rare genetic disorder that is inherited in an autosomal dominant pattern. It is characterised by the early onset of various cancers, including sarcoma, breast cancer, and leukaemia. The condition is caused by mutations in the p53 gene, which can lead to a loss of its tumour-suppressing function. Understanding the role of p53 in cancer can help researchers develop new treatments and therapies for those affected by the disease.

    • This question is part of the following fields:

      • General Principles
      14.9
      Seconds
  • Question 12 - Which one of the following statements relating to osteomyelitis is not true? ...

    Incorrect

    • Which one of the following statements relating to osteomyelitis is not true?

      Your Answer: Plain radiographs may be normal in the early stages

      Correct Answer: Should be treated by aggressive surgical debridement initially

      Explanation:

      The initial management involves medical treatment with an antistaphylococcal antibiotic, as opposed to septic joints where prompt joint washout is necessary.

      Understanding Osteomyelitis: Types, Causes, and Treatment

      Osteomyelitis is a bone infection that can be classified into two types: haematogenous and non-haematogenous. Haematogenous osteomyelitis is caused by bacteria in the bloodstream and is usually monomicrobial. It is more common in children and can be caused by risk factors such as sickle cell anaemia, intravenous drug use, immunosuppression, and infective endocarditis. On the other hand, non-haematogenous osteomyelitis is caused by the spread of infection from adjacent soft tissues or direct injury to the bone. It is often polymicrobial and more common in adults, with risk factors such as diabetic foot ulcers, pressure sores, diabetes mellitus, and peripheral arterial disease.

      Staphylococcus aureus is the most common cause of osteomyelitis, except in patients with sickle-cell anaemia where Salmonella species are more prevalent. To diagnose osteomyelitis, MRI is the imaging modality of choice, with a sensitivity of 90-100%.

      The treatment for osteomyelitis involves a course of antibiotics for six weeks. Flucloxacillin is the preferred antibiotic, but clindamycin can be used for patients who are allergic to penicillin. Understanding the types, causes, and treatment of osteomyelitis is crucial in managing this bone infection.

    • This question is part of the following fields:

      • Musculoskeletal System And Skin
      19.4
      Seconds
  • Question 13 - A 25-year-old male presents to the emergency department with upper abdominal pain that...

    Incorrect

    • A 25-year-old male presents to the emergency department with upper abdominal pain that radiates to the back. This started a few hours previously and has been accompanied by some nausea and vomiting. The patient denies any alcohol intake recently.

      On examination, he has tenderness in the epigastric and right upper quadrant regions. He has a fever of 38.9°C. An ultrasound scan reveals no evidence of gallstones. The patient is given a preliminary diagnosis of acute pancreatitis and some blood tests are requested.

      What could be the cause of this patient's condition?

      Your Answer: Gastroenteritis

      Correct Answer: Mumps

      Explanation:

      Mumps is a known cause of acute pancreatitis, but it has become rare since the introduction of the MMR vaccine. In 2018, there were only 1088 cases of mumps in the UK, which statistically translates to around 54 cases of acute pancreatitis secondary to mumps. Inflammatory bowel disease may also lead to pancreatitis, but it is usually caused by gallstones or medication used to treat IBD. While influenzae and gastroenteritis are not commonly associated with pancreatitis, there have been a few reported cases linking influenzae A to acute pancreatitis, although these occurrences are extremely rare.

      Acute pancreatitis is a condition that is primarily caused by gallstones and alcohol consumption in the UK. However, there are other factors that can contribute to the development of this condition. A popular mnemonic used to remember these factors is GET SMASHED, which stands for gallstones, ethanol, trauma, steroids, mumps, autoimmune diseases, scorpion venom, hypertriglyceridaemia, hyperchylomicronaemia, hypercalcaemia, hypothermia, ERCP, and certain drugs. It is important to note that pancreatitis is seven times more common in patients taking mesalazine than sulfasalazine. CT scans can show diffuse parenchymal enlargement with oedema and indistinct margins in patients with acute pancreatitis.

    • This question is part of the following fields:

      • Gastrointestinal System
      52.3
      Seconds
  • Question 14 - Sarah is a 28-year-old teacher who has presented to the emergency department with...

    Incorrect

    • Sarah is a 28-year-old teacher who has presented to the emergency department with a sudden onset of a severe headache and visual disturbances. Her medical history is significant only for asthma. She does not take any medications, does not smoke nor drink alcohol.

      Upon examination, Sarah is alert and oriented but in obvious pain. Neurological examination reveals a fixed, dilated, non-reactive left pupil that is hypersensitive to light. All extra ocular movements are intact and there is no relative afferent pupillary defect. Systematic enquiry reveals no other abnormalities.

      What is the most likely cause of Sarah's symptoms?

      Your Answer: Closed angle glaucoma

      Correct Answer: Posterior communicating artery aneurysm

      Explanation:

      Understanding Third Nerve Palsy: Causes and Features

      Third nerve palsy is a neurological condition that affects the third cranial nerve, which controls the movement of the eye and eyelid. The condition is characterized by the eye being deviated ‘down and out’, ptosis, and a dilated pupil. In some cases, it may be referred to as a ‘surgical’ third nerve palsy due to the dilation of the pupil.

      There are several possible causes of third nerve palsy, including diabetes mellitus, vasculitis (such as temporal arteritis or SLE), uncal herniation through tentorium if raised ICP, posterior communicating artery aneurysm, and cavernous sinus thrombosis. In some cases, it may also be a false localizing sign. Weber’s syndrome, which is characterized by an ipsilateral third nerve palsy with contralateral hemiplegia, is caused by midbrain strokes. Other possible causes include amyloid and multiple sclerosis.

    • This question is part of the following fields:

      • Neurological System
      35.8
      Seconds
  • Question 15 - A 50-year-old female patient presents to the vascular clinic for evaluation of varicose...

    Incorrect

    • A 50-year-old female patient presents to the vascular clinic for evaluation of varicose veins. During the assessment, a test is conducted to determine the site of incompetence. The patient is instructed to lie down, and her legs are raised to empty the veins. A constricting band is then placed below the sapheno-femoral junction, and the patient is asked to stand up to observe for varicose vein filling. What is the name of this test?

      Your Answer: Buerger's test

      Correct Answer: Tourniquet test

      Explanation:

      Tests for Varicose Veins and Arterial Insufficiency

      The Trendelenburg and tourniquet tests are both used to evaluate the site of incompetence in varicose veins at the sapheno-femoral junction. During the Trendelenburg test, the examiner applies pressure with their fingers over the junction, while in the tourniquet test, a tourniquet is placed just below the junction. If the veins fill rapidly upon standing, it suggests that the sapheno-femoral junction is not the source of the incompetence.

      Buerger’s test is used to assess the arterial circulation of the lower limb. The lower the angle at which blanching occurs, the more likely there is arterial insufficiency. This test is important in diagnosing peripheral artery disease.

      The ankle-brachial pressure index (ABPI) is another test used to assess arterial insufficiency. Blood pressure cuffs are used to measure the systolic blood pressure in the ankle and arm. The ratio of the two pressures is calculated, and a lower ratio indicates a higher degree of claudication.

      Finally, Perthe’s test is used to assess the patency of the deep femoral vein before varicose vein surgery. This test involves compressing the vein and observing the filling of the superficial veins. If the superficial veins fill quickly, it suggests that the deep femoral vein is patent and can be used for surgery.

      In summary, these tests are important in diagnosing and evaluating varicose veins and arterial insufficiency. They help healthcare professionals determine the best course of treatment for their patients.

    • This question is part of the following fields:

      • Basic Sciences
      14
      Seconds
  • Question 16 - A 50-year-old man is having a lymph node biopsy taken from the posterior...

    Correct

    • A 50-year-old man is having a lymph node biopsy taken from the posterior triangle of his neck. What structure creates the posterior boundary of this area?

      Your Answer: Trapezius muscle

      Explanation:

      The posterior triangle of the neck is an area that is bound by the sternocleidomastoid and trapezius muscles, the occipital bone, and the middle third of the clavicle. Within this triangle, there are various nerves, vessels, muscles, and lymph nodes. The nerves present include the accessory nerve, phrenic nerve, and three trunks of the brachial plexus, as well as branches of the cervical plexus such as the supraclavicular nerve, transverse cervical nerve, great auricular nerve, and lesser occipital nerve. The vessels found in this area are the external jugular vein and subclavian artery. Additionally, there are muscles such as the inferior belly of omohyoid and scalene, as well as lymph nodes including the supraclavicular and occipital nodes.

    • This question is part of the following fields:

      • Cardiovascular System
      13.5
      Seconds
  • Question 17 - A 35-year-old man, with a history of type 1 diabetes, was discovered disoriented...

    Incorrect

    • A 35-year-old man, with a history of type 1 diabetes, was discovered disoriented on the road. He was taken to the ER and diagnosed with hypoglycemia. As IV access was not feasible, IM glucagon was administered. What accurately explains the medication's mechanism of action?

      Your Answer: Increases secretion of desmopressin

      Correct Answer: Increases secretion of somatostatin

      Explanation:

      Somatostatin, a hormone that inhibits the secretion of insulin and glucagon, is produced in the pancreas. Glucagon can increase the secretion of somatostatin through a feedback mechanism, while insulin can decrease it. Somatostatin also plays a role in controlling the emptying of the stomach and bowel.

      Glucagon is a treatment option for hypoglycemia, along with IV dextrose if the patient is confused and IV access is available.

      Cortisol is produced in the adrenal gland’s zona fasciculate and is triggered by ACTH, which is released from the anterior pituitary gland. Glucagon can stimulate ACTH-induced cortisol release.

      Desmopressin is an analogue of vasopressin and is used to replace vasopressin/ADH in the treatment of central diabetes insipidus, where there is a lack of ADH due to decreased or non-existent secretion or production by the hypothalamus or posterior pituitary.

      Prolactin, produced in the anterior pituitary, is responsible for milk production in the breasts.

      Somatostatin: The Inhibitor Hormone

      Somatostatin, also known as growth hormone inhibiting hormone (GHIH), is a hormone produced by delta cells found in the pancreas, pylorus, and duodenum. Its main function is to inhibit the secretion of growth hormone, insulin, and glucagon. It also decreases acid and pepsin secretion, as well as pancreatic enzyme secretion. Additionally, somatostatin inhibits the trophic effects of gastrin and stimulates gastric mucous production.

      Somatostatin analogs are commonly used in the management of acromegaly, a condition characterized by excessive growth hormone secretion. These analogs work by inhibiting growth hormone secretion, thereby reducing the symptoms associated with acromegaly.

      The secretion of somatostatin is regulated by various factors. Its secretion increases in response to fat, bile salts, and glucose in the intestinal lumen, as well as glucagon. On the other hand, insulin decreases the secretion of somatostatin.

      In summary, somatostatin plays a crucial role in regulating the secretion of various hormones and enzymes in the body. Its inhibitory effects on growth hormone, insulin, and glucagon make it an important hormone in the management of certain medical conditions.

    • This question is part of the following fields:

      • Endocrine System
      19.8
      Seconds
  • Question 18 - What is the mechanism of action of amiloride for elderly patients? ...

    Incorrect

    • What is the mechanism of action of amiloride for elderly patients?

      Your Answer: Inhibits the Na-K-Cl cotransporter in the thick ascending limb of the loop of Henle

      Correct Answer: Blocks the epithelial sodium channel in the distal convoluted tubule

      Explanation:

      Potassium-sparing diuretics are classified into two types: epithelial sodium channel blockers (such as amiloride and triamterene) and aldosterone antagonists (such as spironolactone and eplerenone). However, caution should be exercised when using these drugs in patients taking ACE inhibitors as they can cause hyperkalaemia. Amiloride is a weak diuretic that blocks the epithelial sodium channel in the distal convoluted tubule. It is usually given with thiazides or loop diuretics as an alternative to potassium supplementation since these drugs often cause hypokalaemia. On the other hand, aldosterone antagonists like spironolactone act in the cortical collecting duct and are used to treat conditions such as ascites, heart failure, nephrotic syndrome, and Conn’s syndrome. In patients with cirrhosis, relatively large doses of spironolactone (100 or 200 mg) are often used to manage secondary hyperaldosteronism.

    • This question is part of the following fields:

      • General Principles
      9.3
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  • Question 19 - The complement cascade can be activated through the classical pathway by forming antibody-antigen...

    Incorrect

    • The complement cascade can be activated through the classical pathway by forming antibody-antigen complexes. Which antibody type is most efficient in carrying out this task?

      Your Answer: IgG

      Correct Answer: IgM

      Explanation:

      Immunoglobulins, also known as antibodies, are proteins produced by the immune system to help fight off infections and diseases. There are five types of immunoglobulins found in the body, each with their own unique characteristics.

      IgG is the most abundant type of immunoglobulin in blood serum and plays a crucial role in enhancing phagocytosis of bacteria and viruses. It also fixes complement and can be passed to the fetal circulation.

      IgA is the most commonly produced immunoglobulin in the body and is found in the secretions of digestive, respiratory, and urogenital tracts and systems. It provides localized protection on mucous membranes and is transported across the interior of the cell via transcytosis.

      IgM is the first immunoglobulin to be secreted in response to an infection and fixes complement, but does not pass to the fetal circulation. It is also responsible for producing anti-A, B blood antibodies.

      IgD’s role in the immune system is largely unknown, but it is involved in the activation of B cells.

      IgE is the least abundant type of immunoglobulin in blood serum and is responsible for mediating type 1 hypersensitivity reactions. It provides immunity to parasites such as helminths and binds to Fc receptors found on the surface of mast cells and basophils.

    • This question is part of the following fields:

      • General Principles
      5.9
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  • Question 20 - A 45-year-old man's prostate-specific antigen (PSA) level is 8.2 ng/mL. He wants to...

    Correct

    • A 45-year-old man's prostate-specific antigen (PSA) level is 8.2 ng/mL. He wants to know the likelihood of having prostate cancer.

      What statistical parameter is required to answer his query?

      Your Answer: Positive predictive value

      Explanation:

      The positive predictive value (PPV) is the probability that a patient has a condition if the diagnostic test is positive. For example, if a patient has a raised PSA level, the PPV would be the chance that they have prostate cancer. It is calculated by dividing the number of true positives by the sum of true positives and false positives.

      On the other hand, the negative predictive value (NPV) is the probability that a patient does not have the condition if the screening test is negative. For instance, if a patient has low PSA levels, the NPV would be the likelihood that they do not have prostate cancer.

      The likelihood ratio is a measure of the usefulness of a diagnostic test. It indicates how much more likely a person with the disease is to have a positive test result compared to a person without the disease. If a patient has already been diagnosed with prostate cancer, a positive likelihood ratio would suggest that the probability of having high PSA levels is higher in patients with prostate cancer than those without it.

      Finally, sensitivity is the proportion of patients with the condition who have a positive test result.

      Precision refers to the consistency of a test in producing the same results when repeated multiple times. It is an important aspect of test reliability and can impact the accuracy of the results. In order to assess precision, multiple tests are performed on the same sample and the results are compared. A test with high precision will produce similar results each time it is performed, while a test with low precision will produce inconsistent results. It is important to consider precision when interpreting test results and making clinical decisions.

    • This question is part of the following fields:

      • General Principles
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  • Question 21 - A pharmaceutical company is conducting tests on a new insulin formulation. As part...

    Correct

    • A pharmaceutical company is conducting tests on a new insulin formulation. As part of their analysis, they have verified that tyrosine kinase receptors are activated by insulin. What is the impact of these receptors on the target molecules?

      Your Answer: Target molecule phosphorylation

      Explanation:

      Activation of tyrosine kinase receptors leads to the phosphorylation of target molecules, which can result in various effects such as cell growth and differentiation. Insulin is an example of a drug that acts through tyrosine kinase receptors. It is important to note that target molecule oxidation, lysis, and reduction are not processes typically associated with tyrosine kinase receptor activation.

      Pharmacodynamics refers to the effects of drugs on the body, as opposed to pharmacokinetics which is concerned with how the body processes drugs. Drugs typically interact with a target, which can be a protein located either inside or outside of cells. There are four main types of cellular targets: ion channels, G-protein coupled receptors, tyrosine kinase receptors, and nuclear receptors. The type of target determines the mechanism of action of the drug. For example, drugs that work on ion channels cause the channel to open or close, while drugs that activate tyrosine kinase receptors lead to cell growth and differentiation.

      It is also important to consider whether a drug has a positive or negative impact on the receptor. Agonists activate the receptor, while antagonists block the receptor preventing activation. Antagonists can be competitive or non-competitive, depending on whether they bind at the same site as the agonist or at a different site. The binding affinity of a drug refers to how readily it binds to a specific receptor, while efficacy measures how well an agonist produces a response once it has bound to the receptor. Potency is related to the concentration at which a drug is effective, while the therapeutic index is the ratio of the dose of a drug resulting in an undesired effect compared to that at which it produces the desired effect.

      The relationship between the dose of a drug and the response it produces is rarely linear. Many drugs saturate the available receptors, meaning that further increased doses will not cause any more response. Some drugs do not have a significant impact below a certain dose and are considered sub-therapeutic. Dose-response graphs can be used to illustrate the relationship between dose and response, allowing for easy comparison of different drugs. However, it is important to remember that dose-response varies between individuals.

    • This question is part of the following fields:

      • General Principles
      30.1
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  • Question 22 - A 50-year-old obese woman presents with right upper quadrant abdominal pain, nausea and...

    Incorrect

    • A 50-year-old obese woman presents with right upper quadrant abdominal pain, nausea and vomiting. She has a family history of gallstone disease. Upon physical examination, a positive Murphy's sign is observed. An abdominal ultrasound reveals gallstones in the thickened gallbladder. The surgeon opts for a laparoscopic cholecystectomy to remove the gallbladder. During the procedure, the surgeon identifies and dissects the hepatobiliary triangle to safely ligate and divide two structures.

      What are the two structures being referred to in the above scenario?

      Your Answer: Common hepatic duct and common bile duct

      Correct Answer: Cystic duct and cystic artery

      Explanation:

      During laparoscopic cholecystectomy, the hepatobiliary triangle plays a crucial role in ensuring the safe ligation and division of the cystic duct and cystic artery. Surgeons must carefully dissect this area to identify these structures and avoid any potential biliary complications.

      The hepatobiliary triangle is bordered by the common hepatic duct, which is formed by the union of the common bile duct and cystic duct. The cystic artery branches off from the right hepatic artery, while Lund’s node serves as the sentinel lymph node of the gallbladder.

      The accessory duct is considered auxiliary to the biliary tree, and the left and right hepatic ducts merge into the common hepatic duct. The gastroduodenal artery arises from the common hepatic artery, and the cystic vein helps distinguish between the cystic and common hepatic ducts during surgery, but is not ligated.

      The gallbladder is a sac made of fibromuscular tissue that can hold up to 50 ml of fluid. Its lining is made up of columnar epithelium. The gallbladder is located in close proximity to various organs, including the liver, transverse colon, and the first part of the duodenum. It is covered by peritoneum and is situated between the right lobe and quadrate lobe of the liver. The gallbladder receives its arterial supply from the cystic artery, which is a branch of the right hepatic artery. Its venous drainage is directly to the liver, and its lymphatic drainage is through Lund’s node. The gallbladder is innervated by both sympathetic and parasympathetic nerves. The common bile duct originates from the confluence of the cystic and common hepatic ducts and is located in the hepatobiliary triangle, which is bordered by the common hepatic duct, cystic duct, and the inferior edge of the liver. The cystic artery is also found within this triangle.

    • This question is part of the following fields:

      • Gastrointestinal System
      21.4
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  • Question 23 - A G2P1 woman visits her obstetrician for a routine antenatal check-up. She is...

    Correct

    • A G2P1 woman visits her obstetrician for a routine antenatal check-up. She is currently 32 weeks pregnant and has had an uneventful pregnancy so far. She denies any symptoms of fatigue, easy bleeding, or bruising.

      During the check-up, her physician orders routine blood tests, and her complete blood count results are as follows:

      - Hemoglobin (Hb): 98 g/L (Male: 135-180, Female: 115-160)
      - Platelets: 110 * 109/L (150-400)
      - White blood cells (WBC): 13 * 109/L (4.0-11.0)

      What is the probable diagnosis?

      Your Answer: Physiological changes of pregnancy

      Explanation:

      During pregnancy, a woman’s body undergoes various physiological changes. The cardiovascular system experiences an increase in stroke volume, heart rate, and cardiac output, while systolic blood pressure remains unchanged and diastolic blood pressure decreases in the first and second trimesters before returning to normal levels by term. The enlarged uterus may cause issues with venous return, leading to ankle swelling, supine hypotension, and varicose veins.

      The respiratory system sees an increase in pulmonary ventilation and tidal volume, with oxygen requirements only increasing by 20%. This can lead to a sense of dyspnea due to over-breathing and a fall in pCO2. The basal metabolic rate also increases, potentially due to increased thyroxine and adrenocortical hormones.

      Maternal blood volume increases by 30%, with red blood cells increasing by 20% and plasma increasing by 50%, leading to a decrease in hemoglobin levels. Coagulant activity increases slightly, while fibrinolytic activity decreases. Platelet count falls, and white blood cell count and erythrocyte sedimentation rate rise.

      The urinary system experiences an increase in blood flow and glomerular filtration rate, with elevated sex steroid levels leading to increased salt and water reabsorption and urinary protein losses. Trace glycosuria may also occur.

      Calcium requirements increase during pregnancy, with gut absorption increasing substantially due to increased 1,25 dihydroxy vitamin D. Serum levels of calcium and phosphate may fall, but ionized calcium levels remain stable. The liver experiences an increase in alkaline phosphatase and a decrease in albumin levels.

      The uterus undergoes significant changes, increasing in weight from 100g to 1100g and transitioning from hyperplasia to hypertrophy. Cervical ectropion and discharge may increase, and Braxton-Hicks contractions may occur in late pregnancy. Retroversion may lead to retention in the first trimester but usually self-corrects.

    • This question is part of the following fields:

      • Reproductive System
      40.4
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  • Question 24 - A patient with Gaucher disease at the age of 50 is recommended enzyme...

    Correct

    • A patient with Gaucher disease at the age of 50 is recommended enzyme replacement therapy using intravenous taliglucerase alfa. During the process, the Golgi apparatus adds a specific molecule to the enzyme to mark it for transportation to the lysosome where it can perform its function.

      What is the name of the molecule that is added to the enzyme for tagging it to the lysosome?

      Your Answer: Mannose 6-phosphate

      Explanation:

      Mannose-6-phosphate is added by Golgi to proteins to facilitate their transport to lysosomes.

      Functions of Cell Organelles

      The functions of major cell organelles can be summarized in a table. The rough endoplasmic reticulum (RER) is responsible for the translation and folding of new proteins, as well as the manufacture of lysosomal enzymes. It is also the site of N-linked glycosylation. Cells such as pancreatic cells, goblet cells, and plasma cells have extensive RER. On the other hand, the smooth endoplasmic reticulum (SER) is involved in steroid and lipid synthesis. Cells of the adrenal cortex, hepatocytes, and reproductive organs have extensive SER.

      The Golgi apparatus modifies, sorts, and packages molecules that are destined for cell secretion. The addition of mannose-6-phosphate to proteins designates transport to lysosome. The mitochondrion is responsible for aerobic respiration and contains mitochondrial genome as circular DNA. The nucleus is involved in DNA maintenance, RNA transcription, and RNA splicing, which removes the non-coding sequences of genes (introns) from pre-mRNA and joins the protein-coding sequences (exons).

      The lysosome is responsible for the breakdown of large molecules such as proteins and polysaccharides. The nucleolus produces ribosomes, while the ribosome translates RNA into proteins. The peroxisome is involved in the catabolism of very long chain fatty acids and amino acids, resulting in the formation of hydrogen peroxide. Lastly, the proteasome, along with the lysosome pathway, is involved in the degradation of protein molecules that have been tagged with ubiquitin.

    • This question is part of the following fields:

      • General Principles
      11.7
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  • Question 25 - A 26 year old female presents to the emergency department with hand tingling...

    Correct

    • A 26 year old female presents to the emergency department with hand tingling following a fall. Upon examination, she is diagnosed with a fracture of the medial epicondyle. What nerve lesion is the most probable cause?

      Your Answer: Ulnar nerve

      Explanation:

      The lateral epicondyle is in close proximity to the radial nerve.

      The ulnar nerve originates from the medial cord of the brachial plexus, specifically from the C8 and T1 nerve roots. It provides motor innervation to various muscles in the hand, including the medial two lumbricals, adductor pollicis, interossei, hypothenar muscles (abductor digiti minimi, flexor digiti minimi), and flexor carpi ulnaris. Sensory innervation is also provided to the medial 1 1/2 fingers on both the palmar and dorsal aspects. The nerve travels through the posteromedial aspect of the upper arm and enters the palm of the hand via Guyon’s canal, which is located superficial to the flexor retinaculum and lateral to the pisiform bone.

      The ulnar nerve has several branches that supply different muscles and areas of the hand. The muscular branch provides innervation to the flexor carpi ulnaris and the medial half of the flexor digitorum profundus. The palmar cutaneous branch arises near the middle of the forearm and supplies the skin on the medial part of the palm, while the dorsal cutaneous branch supplies the dorsal surface of the medial part of the hand. The superficial branch provides cutaneous fibers to the anterior surfaces of the medial one and one-half digits, and the deep branch supplies the hypothenar muscles, all the interosseous muscles, the third and fourth lumbricals, the adductor pollicis, and the medial head of the flexor pollicis brevis.

      Damage to the ulnar nerve at the wrist can result in a claw hand deformity, where there is hyperextension of the metacarpophalangeal joints and flexion at the distal and proximal interphalangeal joints of the 4th and 5th digits. There may also be wasting and paralysis of intrinsic hand muscles (except for the lateral two lumbricals), hypothenar muscles, and sensory loss to the medial 1 1/2 fingers on both the palmar and dorsal aspects. Damage to the nerve at the elbow can result in similar symptoms, but with the addition of radial deviation of the wrist. It is important to diagnose and treat ulnar nerve damage promptly to prevent long-term complications.

    • This question is part of the following fields:

      • Neurological System
      26.9
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  • Question 26 - A 32-year-old female has a sub total thyroidectomy. After five days, the wound...

    Incorrect

    • A 32-year-old female has a sub total thyroidectomy. After five days, the wound starts discharging pus and becomes erythematous. What organism is most likely responsible for this infection?

      Your Answer: Streptococcus pyogenes

      Correct Answer: Staphylococcus aureus

      Explanation:

      Staph aureus was responsible for the majority of infections, as per the given situation. Infections caused by strep pyogenes and other organisms were infrequent.

      Surgical site infections (SSI) are a common complication following surgery, occurring when normal bacteria and other pathogens enter the body through a breach in tissue surfaces. These infections can cause significant morbidity and mortality, with up to 20% of all healthcare-associated infections being SSIs. Patients undergoing surgery have at least a 5% chance of developing an SSI. In many cases, the bacteria causing the infection come from the patient’s own body. Certain measures can increase the risk of SSI, such as using a razor to shave the wound or using a non-iodine impregnated incise drape.

      To prevent SSI, certain steps can be taken before, during, and after surgery. Body hair should not be removed routinely, but if necessary, electrical clippers with a single-use head should be used instead of razors. Antibiotic prophylaxis should be given for certain types of surgery, and a single-dose IV antibiotic should be given on anesthesia. If a tourniquet is used, prophylactic antibiotics should be given earlier. During surgery, the skin should be prepared with alcoholic chlorhexidine, and the surgical site should be covered with a dressing. Postoperatively, tissue viability advice should be given for managing surgical wounds healing by secondary intention.

      The use of diathermy for skin incisions is not recommended in the NICE guidelines, as several randomized controlled trials have shown no increase in the risk of SSI when diathermy is used. It has also been found that wound edge protectors do not provide any benefit in preventing SSI. A recent meta-analysis has shown that the administration of supplementary oxygen does not reduce the risk of wound infection, contrary to previous individual RCTs. By following these preventative measures, the risk of SSI can be significantly reduced, leading to better outcomes for patients undergoing surgery.

    • This question is part of the following fields:

      • General Principles
      14.7
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  • Question 27 - A 24-year-old male patient arrives at the Emergency Department complaining of abdominal pain,...

    Incorrect

    • A 24-year-old male patient arrives at the Emergency Department complaining of abdominal pain, nausea, vomiting, and a decreased level of consciousness. Upon examination, the patient exhibits Kussmaul respiration and an acetone-like breath odor.

      What type of metabolic disturbance is most consistent with the symptoms and presentation of this patient?

      Your Answer: Metabolic acidosis, oxygen dissociation curve shifts to the left

      Correct Answer: Metabolic acidosis, oxygen dissociation curve shifts to the right

      Explanation:

      The correct answer is that metabolic acidosis shifts the oxygen dissociation curve to the right. This is seen in the condition described in the question, diabetic ketoacidosis, which is associated with metabolic acidosis. Acidosis causes more oxygen to be unloaded from haemoglobin, leading to a rightward shift in the curve. The other answer options are incorrect, as they either describe a different type of acidosis or an incorrect direction of the curve shift.

      Understanding the Oxygen Dissociation Curve

      The oxygen dissociation curve is a graphical representation of the relationship between the percentage of saturated haemoglobin and the partial pressure of oxygen in the blood. It is not influenced by the concentration of haemoglobin. The curve can shift to the left or right, indicating changes in oxygen delivery to tissues. When the curve shifts to the left, there is increased saturation of haemoglobin with oxygen, resulting in decreased oxygen delivery to tissues. Conversely, when the curve shifts to the right, there is reduced saturation of haemoglobin with oxygen, leading to enhanced oxygen delivery to tissues.

      The L rule is a helpful mnemonic to remember the factors that cause a shift to the left, resulting in lower oxygen delivery. These factors include low levels of hydrogen ions (alkali), low partial pressure of carbon dioxide, low levels of 2,3-diphosphoglycerate, and low temperature. On the other hand, the mnemonic ‘CADET, face Right!’ can be used to remember the factors that cause a shift to the right, leading to raised oxygen delivery. These factors include carbon dioxide, acid, 2,3-diphosphoglycerate, exercise, and temperature.

      Understanding the oxygen dissociation curve is crucial in assessing the oxygen-carrying capacity of the blood and the delivery of oxygen to tissues. By knowing the factors that can shift the curve to the left or right, healthcare professionals can make informed decisions in managing patients with respiratory and cardiovascular diseases.

    • This question is part of the following fields:

      • Respiratory System
      36.2
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  • Question 28 - A 43-year-old woman visits her GP complaining of a lump in her right...

    Correct

    • A 43-year-old woman visits her GP complaining of a lump in her right breast, fatigue, and unexplained weight loss that has been present for 4 months. During the examination, a nodular lump is discovered in the right axillary tail, and she is referred to the urgent breast cancer clinic.

      At the clinic, the lump undergoes a triple assessment, which reveals an invasive ductal carcinoma. The patient is then subjected to further testing, including genetic testing. The results of the genetic testing show a nonsense mutation that down-regulates a gene responsible for preventing entry into the S phase of the cell cycle.

      What is the likely gene that has been mutated in this patient?

      Your Answer: p53

      Explanation:

      Understanding p53 and its Role in Cancer

      p53 is a gene that helps suppress tumours and is located on chromosome 17p. It is frequently mutated in breast, colon, and lung cancer. The gene is believed to be essential in regulating the cell cycle, preventing cells from entering the S phase until DNA has been checked and repaired. Additionally, p53 may play a crucial role in apoptosis, the process of programmed cell death.

      Li-Fraumeni syndrome is a rare genetic disorder that is inherited in an autosomal dominant pattern. It is characterised by the early onset of various cancers, including sarcoma, breast cancer, and leukaemia. The condition is caused by mutations in the p53 gene, which can lead to a loss of its tumour-suppressing function. Understanding the role of p53 in cancer can help researchers develop new treatments and therapies for those affected by the disease.

    • This question is part of the following fields:

      • General Principles
      20.9
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  • Question 29 - A 35-year-old man comes to the clinic with a complaint of blurred vision...

    Incorrect

    • A 35-year-old man comes to the clinic with a complaint of blurred vision in both eyes for the past week. He also reports seeing floaters and blind spots. He was diagnosed with human immunodeficiency virus (HIV) a couple of years ago and his most recent CD4 count is 20 cells/mm³. Upon fundoscopy, retinitis is observed. What is the probable organism responsible for this condition?

      Your Answer: Cryptosporidium

      Correct Answer: Cytomegalovirus

      Explanation:

      The risk of developing CMV retinitis is highest when the CD4 count drops below 50 cells/mm³. This condition can cause eye symptoms such as floaters, blind spots, and reduced visual acuity, which can eventually lead to blindness.

      On the other hand, cryptosporidiosis typically occurs at a higher CD4 count of 200-500 cells/mm³ and does not cause eye symptoms. Its common symptoms include diarrhea and abdominal pain. Aspergillosis usually manifests at a CD4 count of 50-100 cells/mm³ and affects the lungs, causing symptoms like coughing, chest pain, and coughing up blood. EBV is a common opportunistic infection in HIV patients, but it can infect patients at a higher CD4 count of 200-500 cells/mm³ and rarely causes eye disorders. However, it can lead to hairy leukoplakia and CNS lymphoma.

      HIV and Opportunistic Infections

      Patients with HIV are at an increased risk of developing opportunistic infections and other disorders due to their weakened immune system. The severity and likelihood of these infections vary depending on the patient’s CD4 count.

      For patients with a CD4 count of 200-500 cells/mm³, common infections include oral thrush, shingles, hairy leukoplakia, and Kaposi sarcoma. As the CD4 count decreases to 100-200 cells/mm³, patients may develop more severe infections such as cerebral toxoplasmosis, progressive multifocal leukoencephalopathy, and pneumocystis jirovecii pneumonia. HIV dementia may also occur at this stage.

      When the CD4 count drops below 100 cells/mm³, patients are at a higher risk of developing aspergillosis, oesophageal candidiasis, cryptococcal meningitis, and primary CNS lymphoma. Finally, for patients with a CD4 count of less than 50 cells/mm³, cytomegalovirus retinitis and Mycobacterium avium-intracellulare infection are common.

      It is important for healthcare providers to monitor the CD4 count of HIV patients and provide appropriate treatment to prevent and manage these opportunistic infections.

    • This question is part of the following fields:

      • General Principles
      20.1
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  • Question 30 - As a medical student working in a general practice, a 63-year-old woman comes...

    Incorrect

    • As a medical student working in a general practice, a 63-year-old woman comes in with swelling in both legs. Which medication is the most probable cause of this symptom?

      Your Answer: Furosemide

      Correct Answer: Amlodipine

      Explanation:

      Peripheral oedema is not a known side effect of aspirin, atorvastatin, or clopidogrel. Furosemide is a suitable treatment for peripheral oedema. On the other hand, amlodipine is frequently linked to peripheral oedema as a side effect.

      Calcium channel blockers are a class of drugs commonly used to treat cardiovascular disease. These drugs target voltage-gated calcium channels found in myocardial cells, cells of the conduction system, and vascular smooth muscle. The different types of calcium channel blockers have varying effects on these areas, making it important to differentiate their uses and actions.

      Verapamil is used to treat angina, hypertension, and arrhythmias. It is highly negatively inotropic and should not be given with beta-blockers as it may cause heart block. Side effects include heart failure, constipation, hypotension, bradycardia, and flushing.

      Diltiazem is used to treat angina and hypertension. It is less negatively inotropic than verapamil, but caution should still be exercised when patients have heart failure or are taking beta-blockers. Side effects include hypotension, bradycardia, heart failure, and ankle swelling.

      Nifedipine, amlodipine, and felodipine are dihydropyridines used to treat hypertension, angina, and Raynaud’s. They affect peripheral vascular smooth muscle more than the myocardium, which means they do not worsen heart failure but may cause ankle swelling. Shorter acting dihydropyridines like nifedipine may cause peripheral vasodilation, resulting in reflex tachycardia. Side effects include flushing, headache, and ankle swelling.

      According to current NICE guidelines, the management of hypertension involves a flow chart that takes into account various factors such as age, ethnicity, and comorbidities. Calcium channel blockers may be used as part of the treatment plan depending on the individual patient’s needs.

    • This question is part of the following fields:

      • General Principles
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  • Question 31 - A 32-year-old male visits the GP after a soccer injury. During the game,...

    Correct

    • A 32-year-old male visits the GP after a soccer injury. During the game, he received a blow to the lateral side of his left leg, causing valgus strain on the knee. The GP suspects an unhappy triad injury. What are the three injuries typically associated with this triad?

      Your Answer: Damage to the medial collateral ligament, medial meniscus and anterior cruciate ligament

      Explanation:

      The unhappy triad refers to a set of knee injuries that happen when the knee experiences a lateral impact causing Valgus stress. This stress leads to tears in the medial collateral ligament and the medial meniscus, which are closely connected. Additionally, the anterior cruciate ligament is also affected and traumatized. However, the lateral collateral ligament, lateral meniscus, and posterior cruciate ligament are not involved in this triad.

      Knee Injuries and Common Causes

      Knee injuries can be caused by a variety of factors, including twisting injuries, dashboard injuries, skiing accidents, and lateral blows to the knee. One common knee injury is the unhappy triad, which involves damage to the anterior cruciate ligament, medial collateral ligament, and meniscus. While the medial meniscus is classically associated with this injury, recent evidence suggests that the lateral meniscus is actually more commonly affected.

      When the anterior cruciate ligament is damaged, it may be the result of twisting injuries. Tests such as the anterior drawer test and Lachman test may be positive if this ligament is damaged. On the other hand, dashboard injuries may cause damage to the posterior cruciate ligament. Damage to the medial collateral ligament is often caused by skiing accidents or valgus stress, and can result in abnormal passive abduction of the knee. Isolated injury to the lateral collateral ligament is uncommon.

      Finally, damage to the menisci can also occur from twisting injuries. Common symptoms of meniscus damage include locking and giving way. Overall, understanding the common causes and symptoms of knee injuries can help individuals seek appropriate treatment and prevent further damage.

    • This question is part of the following fields:

      • Musculoskeletal System And Skin
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  • Question 32 - A 20-year-old male is having surgery to remove his appendix due to appendicitis....

    Incorrect

    • A 20-year-old male is having surgery to remove his appendix due to appendicitis. Where is the appendix typically located in the body?

      Your Answer: Post ileal

      Correct Answer: Retrocaecal

      Explanation:

      The majority of appendixes are located in the retrocaecal position. In cases where removal of a retrocaecal appendix proves challenging, mobilizing the right colon can greatly enhance accessibility.

      Appendix Anatomy and Location

      The appendix is a small, finger-like projection located at the base of the caecum. It can be up to 10cm long and is mainly composed of lymphoid tissue, which can sometimes lead to confusion with mesenteric adenitis. The caecal taenia coli converge at the base of the appendix, forming a longitudinal muscle cover over it. This convergence can aid in identifying the appendix during surgery, especially if it is retrocaecal and difficult to locate. The arterial supply to the appendix comes from the appendicular artery, which is a branch of the ileocolic artery. It is important to note that the appendix is intra-peritoneal.

      McBurney’s Point and Appendix Positions

      McBurney’s point is a landmark used to locate the appendix during physical examination. It is located one-third of the way along a line drawn from the Anterior Superior Iliac Spine to the Umbilicus. The appendix can be found in six different positions, with the retrocaecal position being the most common at 74%. Other positions include pelvic, postileal, subcaecal, paracaecal, and preileal. It is important to be aware of these positions as they can affect the presentation of symptoms and the difficulty of locating the appendix during surgery.

    • This question is part of the following fields:

      • Gastrointestinal System
      14
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  • Question 33 - Liam, who is also suffering from chronic pancreatitis, undergoes a distal pancreatectomy. During...

    Incorrect

    • Liam, who is also suffering from chronic pancreatitis, undergoes a distal pancreatectomy. During a post-surgery consultation, he expresses his concern to the doctor about the possibility of experiencing poor food digestion after the operation, as he has read about others who have had the same issue. What measures can the doctor take to prevent this from happening to Liam?

      Your Answer: Refer her to a dietitian for advice regarding her diet

      Correct Answer: Prescribe pancreatic enzymes (e.g. Creon)

      Explanation:

      To aid digestion of food in patients with chronic pancreatitis, the management plan includes the replacement of pancreatic enzymes such as Creon. Inadequacy of pancreatic enzymes due to pancreatic surgery can also lead to poor digestion of food, which can be prevented by providing patients with pancreatic enzyme supplements like Creon. However, proton pump inhibitors or probiotics are not effective in replacing pancreatic enzymes. Fiona does not require a low fibre diet.

      Understanding Chronic Pancreatitis

      Chronic pancreatitis is a condition characterized by inflammation that can affect both the exocrine and endocrine functions of the pancreas. While alcohol excess is the leading cause of this condition, up to 20% of cases are unexplained. Other causes include genetic factors such as cystic fibrosis and haemochromatosis, as well as ductal obstruction due to tumors, stones, and structural abnormalities.

      Symptoms of chronic pancreatitis include pain that worsens 15 to 30 minutes after a meal, steatorrhoea, and diabetes mellitus. Abdominal x-rays and CT scans are used to detect pancreatic calcification, which is present in around 30% of cases. Functional tests such as faecal elastase may also be used to assess exocrine function if imaging is inconclusive.

      Management of chronic pancreatitis involves pancreatic enzyme supplements, analgesia, and antioxidants. While there is limited evidence to support the use of antioxidants, one study suggests that they may be beneficial in early stages of the disease. Overall, understanding the causes and symptoms of chronic pancreatitis is crucial for effective management and treatment.

    • This question is part of the following fields:

      • Gastrointestinal System
      29.8
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  • Question 34 - A 61-year-old man is being evaluated during the ward round in the ICU....

    Incorrect

    • A 61-year-old man is being evaluated during the ward round in the ICU. The patient was admitted through the emergency department with his wife who reported that he had lost consciousness.

      During the examination, the patient is able to move his eyes spontaneously and can perform different eye movements as instructed. However, the patient seems incapable of responding verbally and has 0/5 power in all four limbs.

      Which artery occlusion is probable to result in this clinical presentation?

      Your Answer: Middle cerebral artery

      Correct Answer: Basilar artery

      Explanation:

      Locked-in syndrome is a rare condition that can be caused by a stroke, particularly of the basilar artery. This can result in quadriplegia and bulbar palsy, while cognition and eye movements may remain intact. Other potential causes of locked-in syndrome include trauma, brain tumours, infection, and demyelination.

      If the anterior cerebral artery is affected by a stroke, the patient may experience contralateral hemiparesis and sensory loss, with the lower extremity being more severely affected than the upper extremity. Additional symptoms may include behavioural abnormalities and incontinence.

      A stroke affecting the middle cerebral artery can cause contralateral hemiparesis and sensory loss, with the face and arm being more severely affected than the lower extremity. Speech and visual deficits are also common.

      Strokes affecting the posterior cerebral artery often result in visual deficits, as the occipital lobe is responsible for vision. This can manifest as contralateral homonymous hemianopia.

      Cerebellar infarcts, such as those affecting the superior cerebellar artery, can be difficult to diagnose as they often present with non-specific symptoms like nausea/vomiting, headache, and dizziness.

      Stroke can affect different parts of the brain depending on which artery is affected. If the anterior cerebral artery is affected, the person may experience weakness and loss of sensation on the opposite side of the body, with the lower extremities being more affected than the upper. If the middle cerebral artery is affected, the person may experience weakness and loss of sensation on the opposite side of the body, with the upper extremities being more affected than the lower. They may also experience vision loss and difficulty with language. If the posterior cerebral artery is affected, the person may experience vision loss and difficulty recognizing objects.

      Lacunar strokes are a type of stroke that are strongly associated with hypertension. They typically present with isolated weakness or loss of sensation on one side of the body, or weakness with difficulty coordinating movements. They often occur in the basal ganglia, thalamus, or internal capsule.

    • This question is part of the following fields:

      • Neurological System
      13.7
      Seconds
  • Question 35 - A 29-year-old woman visits her family physician with complaints of vaginal discomfort and...

    Incorrect

    • A 29-year-old woman visits her family physician with complaints of vaginal discomfort and grayish discharge for the past two days. She is sexually active with her husband and has never been pregnant. The physician confirms the presence of thin, grayish discharge with a fishy odor but finds no inflammation. The patient has no history of multiple sexual partners or illicit drug use, and a pregnancy test is negative. The doctor prescribes clindamycin for treatment and advises that the patient's husband does not need to be treated. What are the correct microscopic and biochemical findings for the pathogenic agent responsible for this patient's condition?

      Your Answer: Pseudohyphae with a discharge pH less than 4.5

      Correct Answer: Clue cells with a discharge of pH greater than 4.5

      Explanation:

      The patient displayed symptoms consistent with bacterial vaginosis, which is characterized by a non-inflamed vagina and a thin, white or grayish discharge. In contrast, candida vulvovaginitis presents with an inflamed vagina and a thick, white, cheese-like discharge, while trichomonas vaginitis is associated with an inflamed vagina and a pH greater than 4.5. Bacterial vaginosis is caused by Gardnerella vaginalis and can be treated with metronidazole or clindamycin, without the need for partner treatment. Trichomonas vaginitis, on the other hand, requires partner treatment and is treated with metronidazole.

      Bacterial vaginosis (BV) is a condition where there is an overgrowth of anaerobic organisms, particularly Gardnerella vaginalis, in the vagina. This leads to a decrease in the amount of lactobacilli, which produce lactic acid, resulting in an increase in vaginal pH. BV is not a sexually transmitted infection, but it is commonly seen in sexually active women. Symptoms include a fishy-smelling vaginal discharge, although some women may not experience any symptoms at all. Diagnosis is made using Amsel’s criteria, which includes the presence of thin, white discharge, clue cells on microscopy, a vaginal pH greater than 4.5, and a positive whiff test. Treatment involves oral metronidazole for 5-7 days, with a cure rate of 70-80%. However, relapse rates are high, with over 50% of women experiencing a recurrence within 3 months. Topical metronidazole or clindamycin may be used as alternatives.

      Bacterial vaginosis during pregnancy can increase the risk of preterm labor, low birth weight, chorioamnionitis, and late miscarriage. It was previously recommended to avoid oral metronidazole in the first trimester and use topical clindamycin instead. However, recent guidelines suggest that oral metronidazole can be used throughout pregnancy. The British National Formulary (BNF) still advises against using high-dose metronidazole regimes. Clue cells, which are vaginal epithelial cells covered with bacteria, can be seen on microscopy in women with BV.

    • This question is part of the following fields:

      • General Principles
      62.7
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  • Question 36 - A 25-year-old man is shot in the abdomen and experiences bleeding. What substance...

    Correct

    • A 25-year-old man is shot in the abdomen and experiences bleeding. What substance will cause vasoconstriction in response to this event?

      Your Answer: Angiotensin II

      Explanation:

      Vasoconstriction is not caused by renin. Angiotensin I is not biologically active. Aldosterone can raise blood pressure, but it does not have direct vasospastic effects.

      Shock is a condition where there is not enough blood flow to the tissues. There are five main types of shock: septic, haemorrhagic, neurogenic, cardiogenic, and anaphylactic. Septic shock is caused by an infection that triggers a particular response in the body. Haemorrhagic shock is caused by blood loss, and there are four classes of haemorrhagic shock based on the amount of blood loss and associated symptoms. Neurogenic shock occurs when there is a disruption in the autonomic nervous system, leading to decreased vascular resistance and decreased cardiac output. Cardiogenic shock is caused by heart disease or direct myocardial trauma. Anaphylactic shock is a severe, life-threatening allergic reaction. Adrenaline is the most important drug in treating anaphylaxis and should be given as soon as possible.

    • This question is part of the following fields:

      • Gastrointestinal System
      15.7
      Seconds
  • Question 37 - In what location is LDL produced? ...

    Correct

    • In what location is LDL produced?

      Your Answer: Liver

      Explanation:

      The Formation and Function of LDL Particles

      Low density lipoprotein (LDL) particles are created in the liver through the conversion of intermediate density lipoprotein (IDL) particles. The liver receives triglycerides and cholesterol esters from chylomicrons, which are then repackaged and secreted into the bloodstream as very low density lipoproteins (VLDL). Lipoprotein lipase on endothelial walls converts VLDL to IDL, which is then converted to LDL by the hepatic tricylglycerol lipase enzyme in the liver.

      LDL particles transport triglycerides to cells that express the LDL receptor on their surfaces, which includes most normal body cells. The LDL binds to the LDL receptor, allowing cholesterol to enter the cells and maintain their cell membrane. While most body cells can produce cholesterol, if an excess amount is received from the bloodstream, endogenous cholesterol production is slowed.

      Macrophages have scavenger receptors that can take up LDL particles from the bloodstream, especially when the particles are modified or oxidized. Lipid-laden macrophages enter the arterial wall and become foam cells, which accumulate in fatty streaks and can become atherosclerotic plaques. the formation and function of LDL particles is crucial in preventing the development of atherosclerosis and related cardiovascular diseases.

    • This question is part of the following fields:

      • Clinical Sciences
      4.8
      Seconds
  • Question 38 - A 65-year-old man is scheduled for a revisional total hip replacement via a...

    Correct

    • A 65-year-old man is scheduled for a revisional total hip replacement via a posterior approach. During the procedure, upon dividing the gluteus maximus along its fiber line, there is sudden arterial bleeding. Which vessel is most likely the source of the bleeding?

      Your Answer: Inferior gluteal artery

      Explanation:

      The internal iliac artery gives rise to the inferior gluteal artery, which travels along the deep side of the gluteus maximus muscle. This artery is often separated when using the posterior approach to the hip joint.

      Anatomy of the Hip Joint

      The hip joint is formed by the articulation of the head of the femur with the acetabulum of the pelvis. Both of these structures are covered by articular hyaline cartilage. The acetabulum is formed at the junction of the ilium, pubis, and ischium, and is separated by the triradiate cartilage, which is a Y-shaped growth plate. The femoral head is held in place by the acetabular labrum. The normal angle between the femoral head and shaft is 130 degrees.

      There are several ligaments that support the hip joint. The transverse ligament connects the anterior and posterior ends of the articular cartilage, while the head of femur ligament (ligamentum teres) connects the acetabular notch to the fovea. In children, this ligament contains the arterial supply to the head of the femur. There are also extracapsular ligaments, including the iliofemoral ligament, which runs from the anterior iliac spine to the trochanteric line, the pubofemoral ligament, which connects the acetabulum to the lesser trochanter, and the ischiofemoral ligament, which provides posterior support from the ischium to the greater trochanter.

      The blood supply to the hip joint comes from the medial circumflex femoral and lateral circumflex femoral arteries, which are branches of the profunda femoris. The inferior gluteal artery also contributes to the blood supply. These arteries form an anastomosis and travel up the femoral neck to supply the head of the femur.

    • This question is part of the following fields:

      • Musculoskeletal System And Skin
      9.5
      Seconds
  • Question 39 - Which of the following statements about odds and odds ratio is accurate? ...

    Incorrect

    • Which of the following statements about odds and odds ratio is accurate?

      Your Answer: When applied to survival analysis is termed the hazard ratio

      Correct Answer: The odds ratio approximates to relative risk if the outcome of interest is rare

      Explanation:

      Understanding Odds and Odds Ratio

      When analyzing data, it is important to understand the difference between odds and probability. Odds are a ratio of the number of people who experience a particular outcome to those who do not. On the other hand, probability is the fraction of times an event is expected to occur in many trials. While probability is always between 0 and 1, odds can be any positive number.

      In case-control studies, odds ratios are the usual reported measure. This ratio compares the odds of a particular outcome with experimental treatment to that of a control group. It is important to note that odds ratios approximate to relative risk if the outcome of interest is rare.

      For example, in a trial comparing the use of paracetamol for dysmenorrhoea compared to placebo, the odds of achieving significant pain relief with paracetamol were 2, while the odds of achieving significant pain relief with placebo were 0.5. Therefore, the odds ratio was 4.

      Understanding odds and odds ratio is crucial in interpreting data and making informed decisions. By knowing the difference between odds and probability and how to calculate odds ratios, researchers can accurately analyze and report their findings.

    • This question is part of the following fields:

      • General Principles
      15.6
      Seconds
  • Question 40 - You are on placement in the intensive care unit. An elderly patient has...

    Incorrect

    • You are on placement in the intensive care unit. An elderly patient has been brought in following a fall. However, the patient has not recovered and the consultant is now performing brain stem testing before considering organ donation.

      As part of this, the consultant rubs a cotton bud against the cornea and assesses to see if the patient blinks.

      What is the sensory innervation to the reflex being tested?

      Your Answer: Cranial nerve II - optic nerve

      Correct Answer: Cranial nerve V - trigeminal nerve

      Explanation:

      The afferent limb of the corneal reflex is the trigeminal nerve (cranial nerve V). When the cornea is stimulated, signals are sent via the ophthalmic branch of the trigeminal nerve to the trigeminal sensory nucleus. This activates the facial motor nucleus, causing motor signals to be sent via the facial nerve to contract the orbicularis oculi muscle and produce a blink response. The optic nerve (cranial nerve II) provides sensory innervation to the pupillary reflex, while the oculomotor nerve (cranial nerve III) provides motor innervation to the sphincter pupillae muscle for pupillary constriction. The glossopharyngeal nerve (cranial nerve IX) provides sensory innervation to the gag reflex, with motor innervation coming from the vagus nerve (cranial nerve X).

      Cranial nerves are a set of 12 nerves that emerge from the brain and control various functions of the head and neck. Each nerve has a specific function, such as smell, sight, eye movement, facial sensation, and tongue movement. Some nerves are sensory, some are motor, and some are both. A useful mnemonic to remember the order of the nerves is Some Say Marry Money But My Brother Says Big Brains Matter Most, with S representing sensory, M representing motor, and B representing both.

      In addition to their specific functions, cranial nerves also play a role in various reflexes. These reflexes involve an afferent limb, which carries sensory information to the brain, and an efferent limb, which carries motor information from the brain to the muscles. Examples of cranial nerve reflexes include the corneal reflex, jaw jerk, gag reflex, carotid sinus reflex, pupillary light reflex, and lacrimation reflex. Understanding the functions and reflexes of the cranial nerves is important in diagnosing and treating neurological disorders.

    • This question is part of the following fields:

      • Neurological System
      22.5
      Seconds
  • Question 41 - What is the conversion of pyruvate before it enters the Krebs cycle? ...

    Correct

    • What is the conversion of pyruvate before it enters the Krebs cycle?

      Your Answer: Acetyl-CoA

      Explanation:

      The Krebs cycle occurs in the mitochondrion and involves the conversion of acetyl-CoA to oxaloacetate. This cycle produces six NADH, two FADH, and two ATP for each molecule of glucose. Pyruvate is converted to acetyl-CoA before entering the Krebs cycle, and water and carbon dioxide are end products. Acetic acid itself has no role in the cycle, but its acetyl group is used to form acetyl-CoA. Some anaerobic bacteria can convert sugars to acetic acid directly.

    • This question is part of the following fields:

      • Basic Sciences
      8.2
      Seconds
  • Question 42 - A 67-year-old woman undergoes surgery for ovarian cancer and subsequently starts adjuvant chemotherapy...

    Correct

    • A 67-year-old woman undergoes surgery for ovarian cancer and subsequently starts adjuvant chemotherapy including paclitaxel. The drug works by disrupting tubulin, a protein that forms microtubules. What is the most accurate explanation of the typical role of these structures?

      Your Answer: Guide movement during intracellular transport and help bind internal organelles

      Explanation:

      Microtubules play a crucial role in guiding intracellular transport and binding internal organelles. They also contribute to the cell’s cytoskeleton, which provides its shape. Although not directly involved in DNA translation, microtubules are essential for DNA segregation during cell division.

      Transmembrane proteins, such as ion channels, are responsible for transporting substances across the cell membrane.

      The smooth endoplasmic reticulum is responsible for synthesizing the lipid membrane.

      The docking and fusion of vesicles with their target organelles are facilitated by proteins called SNAREs, which are present on the surface of both the vesicles and the target organelles.

      Microtubules: Components of the Cytoskeleton

      Microtubules are cylindrical structures found in the cytoplasm of all cells except red blood cells. They are composed of alternating α and β tubulin subunits that polymerize to form protofilaments. Microtubules are polarized, having a positive and negative end. They play a crucial role in guiding movement during intracellular transport and binding internal organelles.

      Molecular transport is facilitated by attachment proteins called dynein and kinesin, which move up and down the microtubules. Dynein moves in a retrograde fashion, down the microtubule towards the centre of the cell (+ve → -ve), while kinesin moves in an anterograde fashion, up the microtubule away from the centre, towards the periphery (-ve → +ve).

      In summary, microtubules are essential components of the cytoskeleton that help maintain cell shape and facilitate intracellular transport. Dynein and kinesin play a crucial role in molecular transport by moving up and down the microtubules.

    • This question is part of the following fields:

      • General Principles
      26.1
      Seconds
  • Question 43 - In the context of acid-base balance, what compensatory mechanisms would be observed in...

    Incorrect

    • In the context of acid-base balance, what compensatory mechanisms would be observed in an individual who has a pH of 7.20 (normal range: 7.35-7.45) and is experiencing metabolic acidosis?

      Your Answer: Decreased respiratory rate

      Correct Answer: Increased respiratory rate

      Explanation:

      Compensation for Metabolic Acidosis

      In cases of metabolic acidosis, the bicarbonate levels in the blood will be low. However, this is not considered a compensation. To increase the blood pH, the respiratory rate will increase, causing a decrease in CO2 levels. This results in a respiratory alkalosis, which compensates for the metabolic acidosis. It is important to note that there is a limit to how much an increased respiratory rate can compensate for a metabolic acidosis. Therefore, it is crucial to address the underlying cause of the metabolic acidosis to prevent further complications.

    • This question is part of the following fields:

      • Clinical Sciences
      20.1
      Seconds
  • Question 44 - A 67-year-old man is brought to the emergency department after a fall and...

    Incorrect

    • A 67-year-old man is brought to the emergency department after a fall and head injury he sustained while walking home. He has a history of multiple similar admissions related to alcohol excess. During his hospital stay, his blood sugar levels remain consistently high and he appears disheveled. There is no significant past medical history.

      What could be the probable reason for the patient's elevated blood glucose levels?

      Your Answer: Cortisol release falling the stress of his injury

      Correct Answer: Destruction of islets of Langerhans cells

      Explanation:

      Chronic pancreatitis can cause diabetes as it destroys the islet of Langerhans cells in the pancreas. This patient has a history of recurrent admissions due to alcohol-related falls, indicating excessive alcohol intake, which is the most common risk factor for chronic pancreatitis. A high sugar diet alone should not consistently elevated blood sugar levels if normal insulin control mechanisms are functioning properly. Gastrointestinal bleeding and the stress response to injury would not immediately raise blood sugar levels. In this case, the patient’s alcohol intake suggests chronic pancreatitis as the cause of elevated blood sugar levels rather than type 2 diabetes mellitus.

      Understanding Chronic Pancreatitis

      Chronic pancreatitis is a condition characterized by inflammation that can affect both the exocrine and endocrine functions of the pancreas. While alcohol excess is the leading cause of this condition, up to 20% of cases are unexplained. Other causes include genetic factors such as cystic fibrosis and haemochromatosis, as well as ductal obstruction due to tumors, stones, and structural abnormalities.

      Symptoms of chronic pancreatitis include pain that worsens 15 to 30 minutes after a meal, steatorrhoea, and diabetes mellitus. Abdominal x-rays and CT scans are used to detect pancreatic calcification, which is present in around 30% of cases. Functional tests such as faecal elastase may also be used to assess exocrine function if imaging is inconclusive.

      Management of chronic pancreatitis involves pancreatic enzyme supplements, analgesia, and antioxidants. While there is limited evidence to support the use of antioxidants, one study suggests that they may be beneficial in early stages of the disease. Overall, understanding the causes and symptoms of chronic pancreatitis is crucial for effective management and treatment.

    • This question is part of the following fields:

      • Gastrointestinal System
      42.6
      Seconds
  • Question 45 - A 33-year-old woman presents to the emergency department with acute illness. Her vital...

    Incorrect

    • A 33-year-old woman presents to the emergency department with acute illness. Her vital signs are as follows.

      Heart rate 96 BPM (60-80)
      Respiratory rate 30 per minute (12-20)
      Temperature 39.2 ºC (35.5-37.5)
      Blood pressure 112/84 mmHg (100-140/60-90)

      An infection is suspected, but the source is unknown. Further investigation with a CT scan of the chest and abdomen reveals a retroperitoneal collection, likely caused by leakage from a damaged retroperitoneal structure.

      Which of the following structures is most likely affected?

      Your Answer: First part of the duodenum

      Correct Answer: Ureter

      Explanation:

      The ureters are located in the retroperitoneal space and damage to them can result in the accumulation of fluid in this area. This retroperitoneal collection may be caused by leaked fluid from the damaged ureter. It is important to note that the ureter is the only retroperitoneal structure among the provided options, making it the most likely cause of the fluid accumulation in this patient.

      To remember the retroperitoneal structures, a helpful mnemonic is SAD PUCKER, which stands for Suprarenal (adrenal) glands, Aorta/inferior vena cava, Duodenum (2nd and 3rd parts), Pancreas (except tail), Ureters, Colon (ascending and descending), Kidneys, Esophagus, and Rectum.

      The retroperitoneal structures are those that are located behind the peritoneum, which is the membrane that lines the abdominal cavity. These structures include the duodenum (2nd, 3rd, and 4th parts), ascending and descending colon, kidneys, ureters, aorta, and inferior vena cava. They are situated in the back of the abdominal cavity, close to the spine. In contrast, intraperitoneal structures are those that are located within the peritoneal cavity, such as the stomach, duodenum (1st part), jejunum, ileum, transverse colon, and sigmoid colon. It is important to note that the retroperitoneal structures are not well demonstrated in the diagram as the posterior aspect has been removed, but they are still significant in terms of their location and function.

    • This question is part of the following fields:

      • Gastrointestinal System
      20.1
      Seconds
  • Question 46 - As a junior doctor in a GP surgery, you are requested to examine...

    Incorrect

    • As a junior doctor in a GP surgery, you are requested to examine an 82-year-old man who has reported a tremor in his left hand. What additional symptoms could indicate the presence of Parkinson's disease?

      Your Answer: Chorea and rigidity

      Correct Answer: Bradykinesia and rigidity

      Explanation:

      Parkinson’s disease is characterized by three main symptoms: tremor at rest, bradykinesia, and rigidity. Nystagmus is not a typical feature of Parkinson’s disease, while chorea is more commonly associated with Huntington’s disease. Although ataxia may be present in Parkinson’s disease, it is more frequently seen in cases of cerebellar lesions.

      Parkinson’s disease is a progressive neurodegenerative disorder that occurs due to the degeneration of dopaminergic neurons in the substantia nigra. This leads to a classic triad of symptoms, including bradykinesia, tremor, and rigidity, which are typically asymmetrical. The disease is more common in men and is usually diagnosed around the age of 65. Bradykinesia is characterized by a poverty of movement, shuffling steps, and difficulty initiating movement. Tremors are most noticeable at rest and typically occur in the thumb and index finger. Rigidity can be either lead pipe or cogwheel, and other features include mask-like facies, flexed posture, and drooling of saliva. Psychiatric features such as depression, dementia, and sleep disturbances may also occur. Diagnosis is usually clinical, but if there is difficulty differentiating between essential tremor and Parkinson’s disease, 123I‑FP‑CIT single photon emission computed tomography (SPECT) may be considered.

    • This question is part of the following fields:

      • Neurological System
      10.3
      Seconds
  • Question 47 - A man in his early fifties comes to the clinic complaining of vomiting...

    Correct

    • A man in his early fifties comes to the clinic complaining of vomiting undigested food for the past few weeks. He reports no abdominal pain, changes in bowel habits, fever, or vertigo. He has type 2 diabetes that is not well controlled. What could be the probable reason for his vomiting?

      Your Answer: Gastric paresis

      Explanation:

      The correct answer is gastric paresis, which is a type of autonomic neuropathy commonly linked to type 2 diabetes. Its symptoms include vomiting undigested food due to the stomach’s inability to digest it properly.

      Gastroenteritis, on the other hand, is characterized by vomiting and diarrhea, along with fever and diffuse abdominal pain. It is caused by an infection.

      Peptic ulcers typically cause upper abdominal pain and can lead to haematemesis, which is not present in this patient’s case.

      Vestibular neuritis may also cause vomiting, but it is usually accompanied by severe vertigo and nystagmus.

      Autonomic Neuropathy: Causes and Features

      Autonomic neuropathy is a condition that affects the autonomic nervous system, which controls involuntary bodily functions such as heart rate, blood pressure, and sweating. The features of autonomic neuropathy include impotence, inability to sweat, and postural hypotension, which is a sudden drop in blood pressure upon standing up. Other symptoms include a loss of decrease in heart rate following deep breathing and dilated pupils following adrenaline instillation.

      There are several causes of autonomic neuropathy, including diabetes, Guillain-Barre syndrome, multisystem atrophy (MSA), Shy-Drager syndrome, Parkinson’s disease, and infections such as HIV, Chagas’ disease, and neurosyphilis. Certain medications, such as antihypertensives and tricyclics, can also cause autonomic neuropathy. In rare cases, a craniopharyngioma, a type of brain tumor, can lead to autonomic neuropathy.

    • This question is part of the following fields:

      • Neurological System
      13.9
      Seconds
  • Question 48 - A 50-year-old man presents with a sudden exacerbation of arthralgia affecting his hands...

    Correct

    • A 50-year-old man presents with a sudden exacerbation of arthralgia affecting his hands and wrists. He also complains of feeling excessively fatigued lately. The patient has a medical history of hypertension and type 2 diabetes mellitus. Upon examination, his BMI is found to be 35 kg/m2. Laboratory tests reveal:

      - Na+ 140 mmol/l
      - K+ 4.2 mmol/l
      - Urea 3.8 mmol/l
      - Creatinine 100 µmol/l
      - Plasma glucose 11.8 mmol/l
      - ALT 150 u/l
      - Serum ferritin 2000 ng/ml

      What is the most probable diagnosis?

      Your Answer: Haemochromatosis

      Explanation:

      Hereditary haemochromatosis is a genetic disorder that affects how the body processes iron. It is inherited in an autosomal recessive pattern. The symptoms in the early stages can be vague and non-specific, such as feeling tired and experiencing joint pain. As the condition progresses, it can lead to chronic liver disease and a condition known as bronze diabetes, which is characterized by iron buildup in the pancreas causing diabetes, and a bronze or grey pigmentation of the skin. Based on the patient’s symptoms of joint pain, elevated ALT levels, and significantly high ferritin levels, it is highly likely that they have haemochromatosis.

      Understanding Haemochromatosis: Symptoms and Complications

      Haemochromatosis is a genetic disorder that affects iron absorption and metabolism, leading to iron accumulation in the body. It is caused by mutations in the HFE gene on both copies of chromosome 6. This disorder is prevalent in people of European descent, with 1 in 10 carrying a mutation in the genes affecting iron metabolism. Early symptoms of haemochromatosis are often non-specific, such as lethargy and arthralgia, and may go unnoticed. However, as the disease progresses, patients may experience fatigue, erectile dysfunction, and skin pigmentation.

      Other complications of haemochromatosis include diabetes mellitus, liver disease, cardiac failure, hypogonadism, and arthritis. While some symptoms are reversible with treatment, such as cardiomyopathy, skin pigmentation, diabetes mellitus, hypogonadotrophic hypogonadism, and arthropathy, liver cirrhosis is irreversible.

    • This question is part of the following fields:

      • Gastrointestinal System
      24.2
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  • Question 49 - A 55-year-old woman who underwent laparoscopic cholecystectomy is being evaluated on postoperative day...

    Incorrect

    • A 55-year-old woman who underwent laparoscopic cholecystectomy is being evaluated on postoperative day 2. She reports multiple episodes of vomiting and passing urine only once since the operation. Her medical history includes poorly controlled hypertension on dual therapy. She is currently taking fenoldopam, ACE inhibitors, calcium channel blockers, atorvastatin, and paracetamol. On physical examination, she has dry mucous membranes and a BMI of 31 kg/m². Her vital signs show a mean arterial pressure of 80 mmHg and a heart rate of 110 beats per minute. Laboratory results reveal:

      Na+ 130 mmol/L (135 - 145)
      K+ 5.1 mmol/L (3.5 - 5.0)
      Creatinine 160 µmol/L (55 - 120)

      What is the most important medication that should be discontinued in this patient?

      Your Answer: Calcium channel blockers

      Correct Answer: ACE inhibitors

      Explanation:

      In cases of acute kidney injury (AKI), it is crucial to identify and treat the underlying cause. However, it is important to note that ACE inhibitors should be discontinued as they can worsen renal function by causing efferent arteriolar vasodilation, leading to a decrease in GFR. On the other hand, atorvastatin should not be stopped as it does not accumulate and worsen renal function, but frequent monitoring is necessary. If AKI is caused by rhabdomyolysis, then statins should be immediately discontinued. Calcium channel blockers do not exacerbate renal impairment, but it is advisable to reduce the dose and withhold them if clinical signs appear. Fenoldopam, on the other hand, does not impair kidney function but rather increases blood flow to the renal cortex and medullary regions by decreasing systemic vascular resistance.

      Acute kidney injury (AKI) is a condition where there is a reduction in renal function following an insult to the kidneys. It was previously known as acute renal failure and can result in long-term impaired kidney function or even death. AKI can be caused by prerenal, intrinsic, or postrenal factors. Patients with chronic kidney disease, other organ failure/chronic disease, a history of AKI, or who have used drugs with nephrotoxic potential are at an increased risk of developing AKI. To prevent AKI, patients at risk may be given IV fluids or have certain medications temporarily stopped.

      The kidneys are responsible for maintaining fluid balance and homeostasis, so a reduced urine output or fluid overload may indicate AKI. Symptoms may not be present in early stages, but as renal failure progresses, patients may experience arrhythmias, pulmonary and peripheral edema, or features of uraemia. Blood tests such as urea and electrolytes can be used to detect AKI, and urinalysis and imaging may also be necessary.

      Management of AKI is largely supportive, with careful fluid balance and medication review. Loop diuretics and low-dose dopamine are not recommended, but hyperkalaemia needs prompt treatment to avoid life-threatening arrhythmias. Renal replacement therapy may be necessary in severe cases. Patients with suspected AKI secondary to urinary obstruction require prompt review by a urologist, and specialist input from a nephrologist is required for cases where the cause is unknown or the AKI is severe.

    • This question is part of the following fields:

      • Renal System
      28.9
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  • Question 50 - A 28-week-old premature baby is born and develops tachypnoea, tachycardia, and chest wall...

    Correct

    • A 28-week-old premature baby is born and develops tachypnoea, tachycardia, and chest wall retractions shortly after birth. The neonate also shows blue discolouration of the skin. The doctor starts administering intravenous fluids and CPAP and informs the parents that the baby's lungs are lacking surfactant, a substance that aids breathing.

      What type of cells produce surfactant?

      Your Answer: Type 2 pneumocytes

      Explanation:

      Infant respiratory distress syndrome, also known as surfactant deficiency disorder, is caused by a lack of surfactant development and is commonly found in premature infants. To identify the correct answer, we must focus on lung cells, excluding paneth cells and microfold cells found in the intestinal epithelium, as well as alveolar macrophages, which are responsible for clearing infections and debris. The correct answer is type 2 pneumocytes, which produce pulmonary surfactant, while type 1 pneumocytes facilitate gas exchange between the alveoli and the blood.

      Surfactant Deficient Lung Disease in Premature Infants

      Surfactant deficient lung disease (SDLD), previously known as hyaline membrane disease, is a condition that affects premature infants. It occurs due to the underproduction of surfactant and the immaturity of the lungs’ structure. The risk of SDLD decreases with gestation, with 50% of infants born at 26-28 weeks and 25% of infants born at 30-31 weeks being affected. Other risk factors include male sex, diabetic mothers, Caesarean section, and being the second born of premature twins.

      The clinical features of SDLD are similar to those of respiratory distress in newborns, including tachypnea, intercostal recession, expiratory grunting, and cyanosis. Chest x-rays typically show a ground-glass appearance with an indistinct heart border.

      Prevention during pregnancy involves administering maternal corticosteroids to induce fetal lung maturation. Management of SDLD includes oxygen therapy, assisted ventilation, and exogenous surfactant given via an endotracheal tube.

    • This question is part of the following fields:

      • General Principles
      12
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Haematology And Oncology (0/1) 0%
Clinical Sciences (3/4) 75%
Cardiovascular System (3/4) 75%
General Principles (8/16) 50%
Gastrointestinal System (2/9) 22%
Neurological System (2/7) 29%
Musculoskeletal System And Skin (2/3) 67%
Basic Sciences (1/2) 50%
Endocrine System (0/1) 0%
Reproductive System (1/1) 100%
Respiratory System (0/1) 0%
Renal System (0/1) 0%
Passmed