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  • Question 1 - A 65-year-old woman is admitted to the ICU with a multidrug-resistant urinary tract...

    Incorrect

    • A 65-year-old woman is admitted to the ICU with a multidrug-resistant urinary tract infection. She has a medical history of type 2 diabetes, hypertension, and a previous cerebrovascular accident. After three days, she experiences an altered sensorium and her urine output has been 100 ml over the past 12 hours. Her creatinine level has increased from 1 mg/dl to almost 5 mg/dl, and her blood pressure is currently 180/100 mmHg. The patient is currently taking amikacin, insulin, atorvastatin, atenolol, ramipril, and clopidogrel.

      Which medication, other than ramipril, should be discontinued for this patient?

      Your Answer: Atenolol

      Correct Answer: Amikacin

      Explanation:

      The patient’s symptoms suggest that they may be experiencing acute kidney injury (AKI) as a result of a severe urinary tract infection and potential sepsis. It is important to note that ACE inhibitors such as ramipril should not be used in cases of AKI, and aminoglycosides like amikacin should also be discontinued. Beta-blockers like atenolol, on the other hand, are generally safe to use in AKI patients and may be preferred over ACE inhibitors and ARBs as antihypertensives. While statins like atorvastatin are generally safe in AKI, they can rarely cause rhabdomyolysis, which can worsen renal function and lead to renal failure. Therefore, patients who experience muscle pain should be evaluated further to rule out the possibility of rhabdomyolysis.

      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
      17.9
      Seconds
  • Question 2 - Which muscle inserts onto the lesser tuberosity of the humerus? ...

    Incorrect

    • Which muscle inserts onto the lesser tuberosity of the humerus?

      Your Answer: Deltoid

      Correct Answer: Subscapularis

      Explanation:

      Most rotator cuff muscles insert into the greater tuberosity, except for subscapularis which inserts into the lesser tuberosity.

      The shoulder joint is a shallow synovial ball and socket joint that is inherently unstable but capable of a wide range of movement. Stability is provided by the muscles of the rotator cuff. The glenoid labrum is a fibrocartilaginous rim attached to the free edge of the glenoid cavity. The fibrous capsule attaches to the scapula, humerus, and tendons of various muscles. Movements of the shoulder joint are controlled by different muscles. The joint is closely related to important anatomical structures such as the brachial plexus, axillary artery and vein, and various nerves and vessels.

    • This question is part of the following fields:

      • Musculoskeletal System And Skin
      12.8
      Seconds
  • Question 3 - A 5-year-old child is presented by their mother with complaints of sticky eyes...

    Correct

    • A 5-year-old child is presented by their mother with complaints of sticky eyes and constant rubbing. Upon examination, you observe crusty flakes around the eyelashes and stickiness in both eyes. You prescribe chloramphenicol 5% eye drops to be used four times a day until symptoms subside and provide a leaflet on bacterial conjunctivitis. What is the correct mechanism of action of this medication?

      Your Answer: Inhibits protein synthesis by acting on 50S ribosomal subunit

      Explanation:

      Chloramphenicol hinders the process of protein synthesis by targeting the 50S ribosomal subunit.

      Amphotericin creates a transmembrane protein that causes the leakage of monovalent ions.

      Penicillin functions by preventing the cross-linking of peptidoglycan cell walls, which disrupts the structural integrity of bacterial cells.

      Rifampicin inhibits DNA-dependent RNA polymerase, leading to the suppression of RNA synthesis and eventual cell death.

      Terbinafine blocks the biosynthesis of ergosterol, a crucial component of fungal cell membranes, by inhibiting squalene epoxidase.

      Antibiotics work in different ways to kill or inhibit the growth of bacteria. The commonly used antibiotics can be classified based on their gross mechanism of action. The first group inhibits cell wall formation by either preventing peptidoglycan cross-linking (penicillins, cephalosporins, carbapenems) or peptidoglycan synthesis (glycopeptides like vancomycin). The second group inhibits protein synthesis by acting on either the 50S subunit (macrolides, chloramphenicol, clindamycin, linezolid, streptogrammins) or the 30S subunit (aminoglycosides, tetracyclines) of the bacterial ribosome. The third group inhibits DNA synthesis (quinolones like ciprofloxacin) or damages DNA (metronidazole). The fourth group inhibits folic acid formation (sulphonamides and trimethoprim), while the fifth group inhibits RNA synthesis (rifampicin). Understanding the mechanism of action of antibiotics is important in selecting the appropriate drug for a particular bacterial infection.

    • This question is part of the following fields:

      • General Principles
      24.1
      Seconds
  • Question 4 - A 29-year-old Turkish woman comes to your clinic complaining of growing fatigue and...

    Incorrect

    • A 29-year-old Turkish woman comes to your clinic complaining of growing fatigue and exhaustion. During the clinical examination, you observe pale conjunctiva and peripheral cyanosis. Her complete blood count and haematinics indicate iron deficiency anaemia. You prescribe a course of ferrous fumarate (iron supplement) and advise her to steer clear of certain things that could hinder its absorption. What is one of the things you tell her to avoid?

      Your Answer: Fava beans

      Correct Answer: Tea

      Explanation:

      The absorption of iron in the intestine may be reduced by tannin, which is present in tea.

      Iron is abundant in fava beans.

      Iron Metabolism: Absorption, Distribution, Transport, Storage, and Excretion

      Iron is an essential mineral that plays a crucial role in various physiological processes. The absorption of iron occurs mainly in the upper small intestine, particularly the duodenum. Only about 10% of dietary iron is absorbed, and ferrous iron (Fe2+) is much better absorbed than ferric iron (Fe3+). The absorption of iron is regulated according to the body’s need and can be increased by vitamin C and gastric acid. However, it can be decreased by proton pump inhibitors, tetracycline, gastric achlorhydria, and tannin found in tea.

      The total body iron is approximately 4g, with 70% of it being present in hemoglobin, 25% in ferritin and haemosiderin, 4% in myoglobin, and 0.1% in plasma iron. Iron is transported in the plasma as Fe3+ bound to transferrin. It is stored in tissues as ferritin, and the lost iron is excreted via the intestinal tract following desquamation.

      In summary, iron metabolism involves the absorption, distribution, transport, storage, and excretion of iron in the body. Understanding these processes is crucial in maintaining iron homeostasis and preventing iron-related disorders.

    • This question is part of the following fields:

      • General Principles
      13.7
      Seconds
  • Question 5 - Sophie is a 2-year-old child being cared for in a neonatal intensive care...

    Correct

    • Sophie is a 2-year-old child being cared for in a neonatal intensive care unit for multi-system organ failure, she is unlikely to see her fourth birthday.

      Her older brother, Jack, is a 9-year-old child who is healthy and doing well in school, except his PE teacher has noticed that Jack has mild difficulties with balance and coordination.

      Genetic testing identified both Sophie and Jack have the same disease affecting their mitochondria, which they inherited from their mother but not from their father.

      What is the most probable biological reason for why Sophie's condition is significantly more severe than Jack's?

      Your Answer: Mitochondrial heteroplasmy

      Explanation:

      Mitochondrial heteroplasmy is the presence of multiple types of mitochondrial DNA within an individual, which can result in variable expression of mitochondrial disease. It is likely that Tom and Emily’s mother has mitochondrial heteroplasmy, which caused her to produce eggs with mitochondria containing different genomes. If a mitochondrion contains unhealthy DNA, it may be poorly functional and result in symptoms such as poor balance and coordination, as seen in Emily. Tom, on the other hand, likely developed from an egg with a high proportion of unhealthy mitochondria, leading to multi-system organ failure and a short life expectancy.

      The condition cannot be autosomal recessive as Tom would need to inherit the condition from both parents, not just his mother. Genetic mosaicism is also unlikely as the question states that the condition was inherited from their mother. X-linked dominant inheritance is also ruled out as it only requires one affected chromosome to cause disease.

      It is important to note that mitochondrial disease severity can be influenced by various factors, including mitochondrial heteroplasmy, genetic mosaicism, and autosomal recessive mutations.

      Mitochondrial diseases are caused by a small amount of double-stranded DNA present in the mitochondria, which encodes protein components of the respiratory chain and some special types of RNA. These diseases are inherited only via the maternal line, as the sperm contributes no cytoplasm to the zygote. None of the children of an affected male will inherit the disease, while all of the children of an affected female will inherit it. Mitochondrial diseases generally encode rare neurological diseases, and there is poor genotype-phenotype correlation due to heteroplasmy, which means that within a tissue or cell, there can be different mitochondrial populations. Muscle biopsy typically shows red, ragged fibers due to an increased number of mitochondria. Examples of mitochondrial diseases include Leber’s optic atrophy, MELAS syndrome, MERRF syndrome, Kearns-Sayre syndrome, and sensorineural hearing loss.

    • This question is part of the following fields:

      • General Principles
      44.5
      Seconds
  • Question 6 - An 88-year-old man is brought by his daughter to see his family physician....

    Correct

    • An 88-year-old man is brought by his daughter to see his family physician. The daughter reports that her father has been getting lost while driving and forgetting important appointments. She also notices that he has been misplacing items around the house and struggling to recognize familiar faces. These symptoms have been gradually worsening over the past 6 months.

      Upon examination, the doctor finds that a recent MRI scan shows increased sulci depth consistent with Alzheimer's disease. The man has not experienced any falls or motor difficulties. He has no significant medical history.

      What is the most likely brain pathology in this patient?

      Your Answer: Extracellular amyloid plaques and intracellular neurofibrillary tangles

      Explanation:

      Alzheimer’s disease is characterized by the deposition of type A-Beta-amyloid protein in cortical plaques and abnormal aggregation of the tau protein in intraneuronal neurofibrillary tangles. A patient presenting with memory problems and decreased ability to recognize faces is likely to have Alzheimer’s disease, with Lewy body dementia and vascular dementia being the main differential diagnoses. Lewy body dementia can be ruled out as the patient does not have any movement symptoms. Vascular dementia typically occurs on a background of vascular risk factors and presents with sudden deteriorations in cognition and memory. The diagnosis of Alzheimer’s disease is supported by MRI findings of increased sulci depth due to brain atrophy following neurodegeneration. Pick’s disease, now known as frontotemporal dementia, is characterized by intracellular tau protein aggregates called Pick bodies and presents with personality changes, language impairment, and emotional disturbances.

      Alzheimer’s disease is a type of dementia that gradually worsens over time and is caused by the degeneration of the brain. There are several risk factors associated with Alzheimer’s disease, including increasing age, family history, and certain genetic mutations. The disease is also more common in individuals of Caucasian ethnicity and those with Down’s syndrome.

      The pathological changes associated with Alzheimer’s disease include widespread cerebral atrophy, particularly in the cortex and hippocampus. Microscopically, there are cortical plaques caused by the deposition of type A-Beta-amyloid protein and intraneuronal neurofibrillary tangles caused by abnormal aggregation of the tau protein. The hyperphosphorylation of the tau protein has been linked to Alzheimer’s disease. Additionally, there is a deficit of acetylcholine due to damage to an ascending forebrain projection.

      Neurofibrillary tangles are a hallmark of Alzheimer’s disease and are partly made from a protein called tau. Tau is a protein that interacts with tubulin to stabilize microtubules and promote tubulin assembly into microtubules. In Alzheimer’s disease, tau proteins are excessively phosphorylated, impairing their function.

    • This question is part of the following fields:

      • Neurological System
      8.7
      Seconds
  • Question 7 - A 50-year-old male visits the doctor with concerns about altered sensation in his...

    Correct

    • A 50-year-old male visits the doctor with concerns about altered sensation in his legs. Upon examination, the doctor observes diminished vibration sensation in his legs, brisk knee reflexes, and absent ankle jerks. The doctor suspects that the patient may be suffering from subacute combined degeneration of the spinal cord.

      What vitamin deficiency is commonly associated with this condition?

      Your Answer: Vitamin B12

      Explanation:

      Subacute combined degeneration of the spinal cord, which typically presents with upper motor neuron signs in the legs, is caused by a deficiency in vitamin B12. Meanwhile, a deficiency in vitamin B1 (thiamine) leads to Wernicke’s encephalopathy, characterized by nystagmus, ophthalmoplegia, and ataxia. Peripheral neuropathy is a common result of vitamin B6 (pyridoxine) deficiency, while angular cheilitis is associated with a lack of vitamin B2 (riboflavin).

      Subacute Combined Degeneration of Spinal Cord

      Subacute combined degeneration of spinal cord is a condition that occurs due to a deficiency of vitamin B12. The dorsal columns and lateral corticospinal tracts are affected, leading to the loss of joint position and vibration sense. The first symptoms are usually distal paraesthesia, followed by the development of upper motor neuron signs in the legs, such as extensor plantars, brisk knee reflexes, and absent ankle jerks. If left untreated, stiffness and weakness may persist.

      This condition is a serious concern and requires prompt medical attention. It is important to maintain a healthy diet that includes sufficient amounts of vitamin B12 to prevent the development of subacute combined degeneration of spinal cord.

    • This question is part of the following fields:

      • Neurological System
      5.8
      Seconds
  • Question 8 - A 78-year-old man with an ST-elevation myocardial infarction receives bivalirudin, aspirin, and clopidogrel...

    Correct

    • A 78-year-old man with an ST-elevation myocardial infarction receives bivalirudin, aspirin, and clopidogrel before undergoing percutaneous coronary intervention. What is the mode of action of bivalirudin?

      Your Answer: Reversible direct thrombin inhibitor

      Explanation:

      Bivalirudin inhibits thrombin directly in a reversible manner.

      Warfarin prevents the conversion of vitamin K to its active hydroquinone form by acting as an antagonist.

      Heparins activate antithrombin II and also form inactive complexes with other clotting factors.

      Aspirin inhibits COX.

      Clopidogrel functions as a/an.

      Bivalirudin: An Anticoagulant for Acute Coronary Syndrome

      Bivalirudin is a medication that acts as a direct thrombin inhibitor, meaning it prevents the formation of blood clots. It is commonly used as an anticoagulant in the treatment of acute coronary syndrome, a condition where blood flow to the heart is blocked or reduced. Bivalirudin is a reversible inhibitor, meaning its effects can be reversed if necessary.

      Acute coronary syndrome is a serious condition that can lead to heart attack or other complications if left untreated. Bivalirudin is an effective treatment option for preventing blood clots and reducing the risk of further complications. Its reversible nature also makes it a safer option for patients who may need to undergo surgery or other procedures while on anticoagulant therapy. Overall, bivalirudin is an important medication in the management of acute coronary syndrome and plays a crucial role in improving patient outcomes.

    • This question is part of the following fields:

      • Cardiovascular System
      9.9
      Seconds
  • Question 9 - A 32-year-old man is having surgery to remove his appendix. During the procedure,...

    Incorrect

    • A 32-year-old man is having surgery to remove his appendix. During the procedure, the external oblique aponeurosis is cut and the underlying muscle is split along its fibers. A strong fibrous structure is found at the medial edge of the incision. What is the most likely structure that will be encountered upon entering this fibrous structure?

      Your Answer: Linea alba

      Correct Answer: Rectus abdominis

      Explanation:

      Upon entry, the structure encountered will be the rectus abdominis muscle, which is surrounded by the rectus sheath.

      Abdominal Incisions: Types and Techniques

      Abdominal incisions are surgical procedures that involve making an opening in the abdominal wall to access the organs inside. The most common approach is the midline incision, which involves dividing the linea alba, transversalis fascia, extraperitoneal fat, and peritoneum. Another type is the paramedian incision, which is parallel to the midline and involves dividing the anterior rectus sheath, rectus, posterior rectus sheath, transversalis fascia, extraperitoneal fat, and peritoneum. The battle incision is similar to the paramedian but involves displacing the rectus medially.

      Other types of abdominal incisions include Kocher’s incision under the right subcostal margin for cholecystectomy, Lanz incision in the right iliac fossa for appendicectomy, gridiron oblique incision centered over McBurney’s point for appendicectomy, Pfannenstiel’s transverse supra-pubic incision primarily used to access pelvic organs, McEvedy’s groin incision for emergency repair of a strangulated femoral hernia, and Rutherford Morrison extraperitoneal approach to the left or right lower quadrants for access to iliac vessels and renal transplantation.

      Each type of incision has its own advantages and disadvantages, and the choice of incision depends on the specific surgical procedure and the surgeon’s preference. Proper closure of the incision is crucial to prevent complications such as infection and hernia formation. Overall, abdominal incisions are important techniques in surgical practice that allow for safe and effective access to the abdominal organs.

    • This question is part of the following fields:

      • Gastrointestinal System
      39.8
      Seconds
  • Question 10 - A study examines whether a new medication for elderly patients with heart failure...

    Incorrect

    • A study examines whether a new medication for elderly patients with heart failure can reduce hospitalizations. How should statistical significance be determined when analyzing the data?

      Your Answer: p-value < power

      Correct Answer:

      Explanation:

      Significance tests are used to determine the likelihood of a null hypothesis being true. The null hypothesis states that two treatments are equally effective, while the alternative hypothesis suggests that there is a difference between the two treatments. The p value is the probability of obtaining a result by chance that is at least as extreme as the observed result, assuming the null hypothesis is true. Two types of errors can occur during significance testing: type I, where the null hypothesis is rejected when it is true, and type II, where the null hypothesis is accepted when it is false. The power of a study is the probability of correctly rejecting the null hypothesis when it is false, and it can be increased by increasing the sample size.

    • This question is part of the following fields:

      • General Principles
      10
      Seconds
  • Question 11 - A senior citizen presents with a squamous cell carcinoma involving the lobule of...

    Correct

    • A senior citizen presents with a squamous cell carcinoma involving the lobule of their ear. Which lymph node is the most probable site of metastasis?

      Your Answer: Superficial cervical nodes

      Explanation:

      The superficial cervical nodes receive drainage from the lobule.

      Lymphatic Drainage of the Auricle

      The auricle, also known as the outer ear, has a specific pattern of lymphatic drainage. The upper half of the lateral surface drains to the superficial parotid lymph nodes, while the cranial surface of the superior half drains to the mastoid nodes and deep cervical lymph nodes. On the other hand, the lower half and lobule of the auricle drain into the superficial cervical lymph nodes. This means that lymphatic fluid from different parts of the auricle is directed to different lymph nodes in the body. Understanding this pattern of drainage is important for medical professionals who may need to assess and treat conditions affecting the ear and surrounding tissues. By knowing which lymph nodes are involved, they can better diagnose and manage any issues that may arise.

    • This question is part of the following fields:

      • Haematology And Oncology
      18.5
      Seconds
  • Question 12 - A 26-year-old male accountant comes to the clinic complaining of weakness in his...

    Correct

    • A 26-year-old male accountant comes to the clinic complaining of weakness in his left arm and right leg. He reports experiencing high levels of stress at work and a recent breakup with his girlfriend. Interestingly, he appears to show little emotional reaction when discussing these events and his motor symptoms. Additionally, he is observed moving his affected limbs normally when he thinks no one is watching. How would you describe his presentation?

      Your Answer: Belle indifference

      Explanation:

      Belle Indifference in Conversion Disorder

      Conversion disorder is a dissociative disorder that arises when emotional stress is transformed into physical health symptoms. One of the characteristic features of this disorder is belle indifference, which is the lack of emotional response to the severe physical disabilities that patients with conversion disorders present with. Although it is rarely seen nowadays, it is still included in the diagnostic criteria of this disorder.

      Belle indifference is typically observed in conversion disorder and is a striking feature of this condition. EEG and MRI may confirm the physical disability, but the patient shows no emotional response to the symptoms. Hypochondriasis, on the other hand, is a condition where the patient believes they have a specific diagnosis, such as cancer. It is important to differentiate between these two conditions as they have different treatment approaches. the features of belle indifference in conversion disorder can aid in the diagnosis and management of this disorder.

    • This question is part of the following fields:

      • Psychiatry
      40.4
      Seconds
  • Question 13 - During a hand examination of a 75-year-old woman, it was observed that her...

    Correct

    • During a hand examination of a 75-year-old woman, it was observed that her fingers had a swan-neck deformity and her thumbs had a Z-shape deformity on both hands. After conducting blood tests, the rheumatologist confirmed the presence of anti-CCP antibodies, indicating a diagnosis of rheumatoid arthritis. Which cells, originating from pluripotent hematopoietic stem cells, are responsible for producing antigen-specific immunoglobulins?

      Your Answer: B cells

      Explanation:

      B cells produce antibodies, which are essential in fighting off new pathogens. T helper cells assist B cells by promoting the production of targeted antibodies.

      Mast cells release inflammatory mediators, contributing to the body’s immune response.

      Dendritic cells present antigens to help recruit white blood cells.

      T cells are responsible for immunological memory and the adaptive immune response.

      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
      12.4
      Seconds
  • Question 14 - The concept of number needed to harm can be described as what? ...

    Correct

    • The concept of number needed to harm can be described as what?

      Your Answer: The number of patients that must receive a particular treatment for one additional patient to experience an adverse outcome.

      Explanation:

      The concept of number needed to treat refers to the number of patients who need to be exposed to a certain risk-factor in order for one additional patient to benefit. Similarly, the number needed to harm refers to the number of patients who need to be exposed to a certain risk-factor in order for one additional patient to be harmed. To calculate the number needed to harm, one can use the formula 1/absolute risk reduction, which is the same formula used to calculate the number needed to treat. However, while the number needed to treat typically applies to therapeutic treatments, the number needed to harm applies to risk-factors for disease.

      Numbers needed to treat (NNT) is a measure that determines how many patients need to receive a particular intervention to reduce the expected number of outcomes by one. To calculate NNT, you divide 1 by the absolute risk reduction (ARR) and round up to the nearest whole number. ARR can be calculated by finding the absolute difference between the control event rate (CER) and the experimental event rate (EER). There are two ways to calculate ARR, depending on whether the outcome of the study is desirable or undesirable. If the outcome is undesirable, then ARR equals CER minus EER. If the outcome is desirable, then ARR is equal to EER minus CER. It is important to note that ARR may also be referred to as absolute benefit increase.

    • This question is part of the following fields:

      • General Principles
      24
      Seconds
  • Question 15 - A 68-year-old male presents with a 6-month history of polyuria and polydipsia. He...

    Correct

    • A 68-year-old male presents with a 6-month history of polyuria and polydipsia. He has a medical history of hypertension, bipolar disorder, and osteoarthritis, and is currently taking naproxen, ramipril, amlodipine, and lithium. His HbA1c level is 41 mmol/mol. A water deprivation test is performed, and the pre-test urine osmolality is 210 mOsm/kg (500-850), while the post-test urine osmolality is 240 mOsm/kg (500-850). Based on the likely diagnosis, which anatomical location has been affected?

      Your Answer: Collecting duct

      Explanation:

      Lithium use in patients can lead to diabetes insipidus by desensitizing the kidney’s response to ADH in the collecting ducts. This is likely the cause of diabetes insipidus in the patient described, as they are on lithium and have no signs of cranial diabetes insipidus. Cranial diabetes insipidus typically results from head trauma or pituitary surgery, while nephrogenic diabetes insipidus is caused by kidney dysfunction.

      The posterior pituitary gland releases ADH, and dysfunction at this site can cause cranial diabetes insipidus. An anterior pituitary tumor may present with bilateral hemianopia, as this gland secretes several hormones.

      Thiazide diuretics act on the distal convoluted tubule and are used to treat diabetes insipidus. Gitelman syndrome is caused by a mutation in the Na+-Cl− co-transporter, while Fanconi syndrome results from dysfunction in the proximal renal tubule, leading to an inability to absorb certain substances.

      Diabetes insipidus is a medical condition that can be caused by either a decreased secretion of antidiuretic hormone (ADH) from the pituitary gland (cranial DI) or an insensitivity to ADH (nephrogenic DI). Cranial DI can be caused by various factors such as head injury, pituitary surgery, and infiltrative diseases like sarcoidosis. On the other hand, nephrogenic DI can be caused by genetic factors, electrolyte imbalances, and certain medications like lithium and demeclocycline. The common symptoms of DI are excessive urination and thirst. Diagnosis is made through a water deprivation test and checking the osmolality of the urine. Treatment options include thiazides and a low salt/protein diet for nephrogenic DI, while central DI can be treated with desmopressin.

    • This question is part of the following fields:

      • Renal System
      36.1
      Seconds
  • Question 16 - A 19-year-old male has been diagnosed with tuberculosis. Which cells are accountable for...

    Correct

    • A 19-year-old male has been diagnosed with tuberculosis. Which cells are accountable for engulfing the mycobacteria in the lung alveoli?

      Your Answer: Macrophages

      Explanation:

      Mycobacterium tuberculosis is transmitted through the air as aerosol particles. When inhaled, the bacteria enter the pulmonary alveoli where they are taken up by alveolar macrophages and begin to multiply. The infected macrophages then transport the bacteria to the hilar lymph nodes in an attempt to contain the infection.

      Other types of cells do not take up the bacteria.

      Understanding Tuberculosis: The Pathophysiology and Risk Factors

      Tuberculosis is a bacterial infection caused by Mycobacterium tuberculosis. The pathophysiology of tuberculosis involves the migration of macrophages to regional lymph nodes, forming a Ghon complex. This complex leads to the formation of a granuloma, which is a collection of epithelioid histiocytes with caseous necrosis in the center. The inflammatory response is mediated by a type 4 hypersensitivity reaction. While healthy individuals can contain the disease, immunocompromised individuals are at risk of developing disseminated (miliary) TB.

      Several risk factors increase the likelihood of developing tuberculosis. These include having lived in Asia, Latin America, Eastern Europe, or Africa for years, exposure to an infectious TB case, and being infected with HIV. Immunocompromised individuals, such as diabetics, patients on immunosuppressive therapy, malnourished individuals, or those with haematological malignancies, are also at risk. Additionally, silicosis and apical fibrosis increase the likelihood of developing tuberculosis. Understanding the pathophysiology and risk factors of tuberculosis is crucial in preventing and treating this infectious disease.

    • This question is part of the following fields:

      • General Principles
      6.2
      Seconds
  • Question 17 - A pair come in to talk about their third pregnancy and are curious...

    Correct

    • A pair come in to talk about their third pregnancy and are curious about how the body organs end up in their proper positions. They've been informed that folding and migration are necessary. As an instance, during embryonic growth, the septum transversum originates at the head of the embryo.

      What is the adult body structure that this serves as a precursor for?

      Your Answer: The diaphragm

      Explanation:

      The septum transversum plays a crucial role in the development of the diaphragm. As the embryo develops, the septum transversum moves to its position between the thorax and abdomen. While the heart and ribcage are also important structures in this area, they are formed from different embryonic tissues. The occipital bone, on the other hand, is formed through a combination of intramembranous and endochondral ossification processes, involving both neural crest cells and mesodermal cells.

      Embryology is the study of the development of an organism from the moment of fertilization to birth. During the first week of embryonic development, the fertilized egg implants itself into the uterine wall. By the second week, the bilaminar disk is formed, consisting of two layers of cells. The primitive streak appears in the third week, marking the beginning of gastrulation and the formation of the notochord.

      As the embryo enters its fourth week, limb buds begin to form, and the neural tube closes. The heart also begins to beat during this time. By week 10, the genitals are differentiated, and the embryo exhibits intermittent breathing movements. These early events in embryonic development are crucial for the formation of the body’s major organs and structures. Understanding the timeline of these events can provide insight into the complex process of human development.

    • This question is part of the following fields:

      • General Principles
      8.6
      Seconds
  • Question 18 - A 47-year-old woman, who is notably tall, visits the surgical clinic due to...

    Correct

    • A 47-year-old woman, who is notably tall, visits the surgical clinic due to bilateral inguinal hernias. During her evaluation, she experiences chest discomfort and faints. A chest x-ray reveals indications of mediastinal widening. What is the probable underlying condition?

      Your Answer: Aortic dissection

      Explanation:

      Individuals with Marfan syndrome may exhibit various connective tissue disorders, including bilateral inguinal hernia. They are particularly susceptible to aortic dissection, as demonstrated in this instance.

      Aortic dissection is a serious condition that can cause chest pain. It occurs when there is a tear in the inner layer of the aorta’s wall. Hypertension is the most significant risk factor, but it can also be associated with trauma, bicuspid aortic valve, and certain genetic disorders. Symptoms of aortic dissection include severe and sharp chest or back pain, weak or absent pulses, hypertension, and aortic regurgitation. Specific arteries’ involvement can cause other symptoms such as angina, paraplegia, or limb ischemia. The Stanford classification divides aortic dissection into type A, which affects the ascending aorta, and type B, which affects the descending aorta. The DeBakey classification further divides type A into type I, which extends to the aortic arch and beyond, and type II, which is confined to the ascending aorta. Type III originates in the descending aorta and rarely extends proximally.

    • This question is part of the following fields:

      • Cardiovascular System
      78.8
      Seconds
  • Question 19 - A man in his 50s arrives at the emergency department with bleeding following...

    Correct

    • A man in his 50s arrives at the emergency department with bleeding following a car accident. Despite significant blood loss, his blood pressure has remained stable. What can be said about the receptors responsible for regulating his blood pressure?

      Your Answer: Baroreceptors are stimulated by arterial stretch

      Explanation:

      Arterial stretch stimulates baroreceptors, which are located at the aortic arch and carotid sinus. The baroreceptor reflex acts on the medulla to regulate parasympathetic and sympathetic activity. When baroreceptors are more stimulated, there is an increase in parasympathetic discharge to the SA node and a decrease in sympathetic discharge. Conversely, reduced stimulation of baroreceptors leads to decreased parasympathetic discharge and increased sympathetic discharge. Baroreceptors are always active, and changes in arterial stretch can either increase or decrease their level of stimulation.

      The heart has four chambers and generates pressures of 0-25 mmHg on the right side and 0-120 mmHg on the left. The cardiac output is the product of heart rate and stroke volume, typically 5-6L per minute. The cardiac impulse is generated in the sino atrial node and conveyed to the ventricles via the atrioventricular node. Parasympathetic and sympathetic fibers project to the heart via the vagus and release acetylcholine and noradrenaline, respectively. The cardiac cycle includes mid diastole, late diastole, early systole, late systole, and early diastole. Preload is the end diastolic volume and afterload is the aortic pressure. Laplace’s law explains the rise in ventricular pressure during the ejection phase and why a dilated diseased heart will have impaired systolic function. Starling’s law states that an increase in end-diastolic volume will produce a larger stroke volume up to a point beyond which stroke volume will fall. Baroreceptor reflexes and atrial stretch receptors are involved in regulating cardiac output.

    • This question is part of the following fields:

      • Cardiovascular System
      25.4
      Seconds
  • Question 20 - Which one of the following statements relating to malignant mesothelioma is not true?...

    Incorrect

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

      Your Answer: It may be treated by extrapleural pneumonectomy.

      Correct Answer: It is linked to cigarette smoking independent of asbestos exposure.

      Explanation:

      This type of cancer is not associated with smoking cigarettes. The preferred treatment option is a complete removal of the tumor if caught early. Radiation therapy is commonly administered before or after surgery, but this type of cancer is not highly responsive to radiation. The most effective treatment involves a combination of chemotherapy drugs, with many regimens utilizing cisplatin.

      Occupational cancers are responsible for 5.3% of cancer deaths, with men being more affected than women. The most common types of cancer in men include mesothelioma, bladder cancer, non-melanoma skin cancer, lung cancer, and sino-nasal cancer. Occupations that have a high risk of developing tumors include those in the construction industry, coal tar and pitch workers, miners, metalworkers, asbestos workers, and those in the rubber industry. Shift work has also been linked to breast cancer in women.

      The latency period between exposure to carcinogens and the development of cancer is typically 15 years for solid tumors and 20 years for leukemia. Many occupational cancers are rare, such as sino-nasal cancer, which is linked to wood dust exposure and is not strongly associated with smoking. Another rare occupational tumor is angiosarcoma of the liver, which is linked to working with vinyl chloride. In non-occupational contexts, these tumors are extremely rare.

    • This question is part of the following fields:

      • Haematology And Oncology
      26.7
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  • Question 21 - A 27-year-old male visits a sexual health clinic due to concerns about a...

    Correct

    • A 27-year-old male visits a sexual health clinic due to concerns about a possible sexually transmitted infection. After a swab is taken, the lab results indicate the presence of gram-negative diplococci. What is the probable causative agent?

      Your Answer: Neisseria gonorrhoeae

      Explanation:

      gonorrhoeae is caused by Neisseria gonorrhoeae, a gram-negative diplococcus that can be identified on gram staining. Another important gram-negative diplococcus to remember is Neisseria meningitidis. Chlamydia trachomatis is not the causative organism for gonorrhoeae, as it is a rod-shaped intracellular bacteria that is hard to stain. Gardnerella vaginalis is not the causative organism for gonorrhoeae, but is often involved in bacterial vaginosis and has a gram-variable cocco-bacilli shape. Trichomonas vaginalis is also not the causative organism for gonorrhoeae, as it is a parasite that causes trichomoniasis.

      Understanding gonorrhoeae: Causes, Symptoms, and Treatment

      gonorrhoeae is a sexually transmitted infection caused by the Gram-negative diplococcus Neisseria gonorrhoeae. It can occur on any mucous membrane surface, including the genitourinary tract, rectum, and pharynx. Symptoms in males include urethral discharge and dysuria, while females may experience cervicitis leading to vaginal discharge. However, rectal and pharyngeal infections are usually asymptomatic. Unfortunately, immunisation is not possible, and reinfection is common due to antigen variation of type IV pili and Opa proteins.

      If left untreated, gonorrhoeae can lead to local complications such as urethral strictures, epididymitis, and salpingitis, which may result in infertility. Disseminated infection may also occur, with gonococcal infection being the most common cause of septic arthritis in young adults. The pathophysiology of disseminated gonococcal infection is not fully understood but is thought to be due to haematogenous spread from mucosal infection.

      Management of gonorrhoeae involves the use of antibiotics. Ciprofloxacin used to be the treatment of choice, but there is now increased resistance to it. Cephalosporins are now more widely used, with a single dose of IM ceftriaxone 1g being the new first-line treatment. If sensitivities are known, a single dose of oral ciprofloxacin 500mg may be given. Disseminated gonococcal infection and gonococcal arthritis may also occur, with symptoms including tenosynovitis, migratory polyarthritis, and dermatitis.

    • This question is part of the following fields:

      • General Principles
      5.5
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  • Question 22 - A three-year-old boy is presented to the pediatrician by his father due to...

    Incorrect

    • A three-year-old boy is presented to the pediatrician by his father due to repeated episodes of otitis media. The pediatrician has attempted delayed antibiotic treatments in the past, but they have not been effective. As the child has a penicillin allergy, the pediatrician follows hospital protocol and prescribes a course of macrolide antibiotic, clarithromycin.

      What is the mode of action of the prescribed antibiotic?

      Your Answer: Prevent cell wall biosynthesis in bacterial organisms

      Correct Answer: Inhibit protein synthesis by binding to a ribosomal subunit and blocking translocation

      Explanation:

      Macrolides prevent protein synthesis by binding to the 50S ribosomal subunit and blocking translocation through their interaction with 23S rRNA. This is the correct mechanism of action.

      Folate antagonists (such as trimethoprim) inhibit cell division by antagonizing vitamin B9, making this answer incorrect.

      Tetracyclines (such as doxycycline) inhibit bacterial growth by binding to bacterial ribosomes, making this answer incorrect.

      Nitroimidazoles (such as metronidazole) disrupt microbial DNA in anaerobic bacteria and protozoa, inhibiting nucleic acid synthesis, making this answer incorrect.

      Macrolides are a class of antibiotics that include erythromycin, clarithromycin, and azithromycin. They work by blocking translocation during bacterial protein synthesis, ultimately inhibiting bacterial growth. While they are generally considered bacteriostatic, their effectiveness can vary depending on the dose and type of organism being treated. Resistance to macrolides can occur through post-transcriptional methylation of the 23S bacterial ribosomal RNA.

      However, macrolides can also have adverse effects. They may cause prolongation of the QT interval and gastrointestinal side-effects, such as nausea. Cholestatic jaundice is a potential risk, but using erythromycin stearate may reduce this risk. Additionally, macrolides are known to inhibit the cytochrome P450 isoenzyme CYP3A4, which metabolizes statins. Therefore, it is important to stop taking statins while on a course of macrolides to avoid the risk of myopathy and rhabdomyolysis. Azithromycin is also associated with hearing loss and tinnitus.

      Overall, while macrolides can be effective antibiotics, they do come with potential risks and side-effects. It is important to weigh the benefits and risks before starting a course of treatment with these antibiotics.

    • This question is part of the following fields:

      • General Principles
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  • Question 23 - A 6-year-old boy arrives at the paediatric emergency department with a non-blanching rash....

    Correct

    • A 6-year-old boy arrives at the paediatric emergency department with a non-blanching rash. He is limping and complaining of abdominal pain. He had a recent bout of tonsillitis but is typically healthy. Upon examination, there are numerous palpable purpura in a symmetrical pattern, mainly on his buttocks and the backs of his legs. A urine dipstick reveals mild proteinuria and 2+ blood.

      What is the probable underlying pathophysiology of this presentation?

      Your Answer: IgA mediated small vessel vasculitis

      Explanation:

      The correct answer is IgA mediated small vessel vasculitis, specifically Henoch-Schonlein purpura (HSP). This condition is characterized by palpable purpura, arthralgia, abdominal pain, and haematuria, and typically affects children aged 4-6 years. HSP is often triggered by infections such as streptococcal pharyngitis, but can also be caused by other infections like Mycoplasma pneumoniae, Epstein-Barr virus, and adenovirus.

      The other options are incorrect. ANCA-associated vasculitis typically involves the respiratory and ENT systems, which this child does not have. Cryoglobulinaemic vasculitis is associated with hepatitis C, haematological malignancies, and autoimmune disease, none of which are present in this case. Deficiency of von Willebrand factor cleaving protein is a feature of TTP, which is rare in children and typically presents with a low platelet count. ITP is another autoimmune condition that can present similarly to HSP, but can be differentiated by a low platelet count.

      Understanding Henoch-Schonlein Purpura

      Henoch-Schonlein purpura (HSP) is a type of small vessel vasculitis that is mediated by IgA. It is often associated with IgA nephropathy, also known as Berger’s disease. HSP is commonly observed in children following an infection.

      The condition is characterized by a palpable purpuric rash, which is accompanied by localized oedema over the buttocks and extensor surfaces of the arms and legs. Other symptoms include abdominal pain and polyarthritis. In some cases, patients may also experience haematuria and renal failure, which are indicative of IgA nephropathy.

      Treatment for HSP typically involves analgesia for arthralgia. While there is inconsistent evidence for the use of steroids and immunosuppressants, supportive care is generally recommended for patients with nephropathy. The prognosis for HSP is usually excellent, particularly in children without renal involvement. However, it is important to monitor blood pressure and urinalysis to detect any signs of progressive renal involvement. Approximately one-third of patients may experience a relapse.

      In summary, Henoch-Schonlein purpura is a self-limiting condition that is often seen in children following an infection. While the symptoms can be uncomfortable, the prognosis is generally good. However, it is important to monitor patients for any signs of renal involvement and provide appropriate supportive care.

    • This question is part of the following fields:

      • Renal System
      45.4
      Seconds
  • Question 24 - During a ward round on the stroke ward, you notice a patient in...

    Incorrect

    • During a ward round on the stroke ward, you notice a patient in their 60s responds to questions with unrelated words and phrases. His speech is technically good and fluent but the sentences make no sense. He does not appear to be aware of this and struggles to understand questions when written down.

      Where is the location of the lesion producing this sign?

      Your Answer: Arcuate fasciculus

      Correct Answer: Superior temporal gyrus

      Explanation:

      Wernicke’s aphasia is caused by damage to the superior temporal gyrus, resulting in fluent speech but poor comprehension and characteristic ‘word salad’. Patients with this type of aphasia are often unaware of their errors.

      Conduction aphasia, on the other hand, is caused by damage to the arcuate fasciculus, which connects Wernicke’s and Broca’s areas. This results in fluent speech with poor repetition, but patients are usually aware of their errors.

      A lesion of the corpus callosum can cause more widespread problems with motor and sensory deficits due to impaired communication between the hemispheres.

      Broca’s area, located in the inferior frontal gyrus, is responsible for expressive aphasia, where speech is non-fluent but comprehension is intact.

      It’s important to note that true aphasia does not involve any motor deficits, so damage to the primary motor cortex would not be the cause.

      Types of Aphasia: Understanding the Different Forms of Language Impairment

      Aphasia is a language disorder that affects a person’s ability to communicate effectively. There are different types of aphasia, each with its own set of symptoms and underlying causes. Wernicke’s aphasia, also known as receptive aphasia, is caused by a lesion in the superior temporal gyrus. This area is responsible for forming speech before sending it to Broca’s area. People with Wernicke’s aphasia may speak fluently, but their sentences often make no sense, and they may use word substitutions and neologisms. Comprehension is impaired.

      Broca’s aphasia, also known as expressive aphasia, is caused by a lesion in the inferior frontal gyrus. This area is responsible for speech production. People with Broca’s aphasia may speak in a non-fluent, labored, and halting manner. Repetition is impaired, but comprehension is normal.

      Conduction aphasia is caused by a stroke affecting the arcuate fasciculus, the connection between Wernicke’s and Broca’s area. People with conduction aphasia may speak fluently, but their repetition is poor. They are aware of the errors they are making, but comprehension is normal.

      Global aphasia is caused by a large lesion affecting all three areas mentioned above, resulting in severe expressive and receptive aphasia. People with global aphasia may still be able to communicate using gestures. Understanding the different types of aphasia is important for proper diagnosis and treatment.

    • This question is part of the following fields:

      • Neurological System
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  • Question 25 - A 26-year-old, gravida 1 para 1, is interested in learning about the pros...

    Incorrect

    • A 26-year-old, gravida 1 para 1, is interested in learning about the pros and cons of breastfeeding her upcoming newborn. She has been researching the benefits of breast milk online, but stumbled upon an article that presented a negative perspective on breastfeeding. As her healthcare provider, you inform her about the numerous advantages of breast milk, but also mention that there are some potential drawbacks.

      What is one recognized disadvantage of breast milk?

      Your Answer: Lactoferrin deficiency

      Correct Answer: Inadequate levels of vitamin K

      Explanation:

      Vitamin K levels in breast milk are insufficient, but lactoferrin levels are adequate and promote iron uptake and have antibacterial properties. Breastfeeding is also linked to lower rates of breast and ovarian cancer, ear infections, and type 1 diabetes mellitus.

      Advantages and Disadvantages of Breastfeeding

      Breastfeeding has numerous advantages for both the mother and the baby. For the mother, it promotes bonding with the baby and helps with the involution of the uterus. It also provides protection against breast and ovarian cancer and is a cheap alternative to formula feeding as there is no need to sterilize bottles. However, it should not be relied upon as a contraceptive method as it is unreliable.

      Breast milk contains immunological components such as IgA, lysozyme, and lactoferrin that protect mucosal surfaces, have bacteriolytic properties, and ensure rapid absorption of iron so it is not available to bacteria. This reduces the incidence of ear, chest, and gastrointestinal infections, as well as eczema, asthma, and type 1 diabetes mellitus. Breastfeeding also reduces the incidence of sudden infant death syndrome.

      One of the advantages of breastfeeding is that the baby is in control of how much milk it takes. However, there are also disadvantages such as the transmission of drugs and infections such as HIV. Prolonged breastfeeding may also lead to nutrient inadequacies such as vitamin D and vitamin K deficiencies, as well as breast milk jaundice.

      In conclusion, while breastfeeding has numerous advantages, it is important to be aware of the potential disadvantages and to consult with a healthcare professional to ensure that both the mother and the baby are receiving adequate nutrition and care.

    • This question is part of the following fields:

      • Reproductive System
      16.9
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  • Question 26 - A 22-year-old man suffers a depressed skull fracture at the vertex after being...

    Incorrect

    • A 22-year-old man suffers a depressed skull fracture at the vertex after being struck with a hammer. Which of the following sinuses is in danger due to this injury?

      Your Answer: Transverse sinus

      Correct Answer: Superior sagittal sinus

      Explanation:

      The pattern of injury poses the highest threat to the superior sagittal sinus, which starts at the crista galli’s front and runs along the falx cerebri towards the back. It merges with the right transverse sinus close to the internal occipital protuberance.

      Overview of Cranial Venous Sinuses

      The cranial venous sinuses are a series of veins located within the dura mater, the outermost layer of the brain. Unlike other veins in the body, they do not have valves, which can increase the risk of sepsis spreading. These sinuses eventually drain into the internal jugular vein.

      There are several cranial venous sinuses, including the superior sagittal sinus, inferior sagittal sinus, straight sinus, transverse sinus, sigmoid sinus, confluence of sinuses, occipital sinus, and cavernous sinus. Each of these sinuses has a specific location and function within the brain.

      To better understand the topography of the cranial venous sinuses, it is helpful to visualize them as a map. The superior sagittal sinus runs along the top of the brain, while the inferior sagittal sinus runs along the bottom. The straight sinus connects the two, while the transverse sinus runs horizontally across the back of the brain. The sigmoid sinus then curves downward and connects to the internal jugular vein. The confluence of sinuses is where several of these sinuses meet, while the occipital sinus is located at the back of the head. Finally, the cavernous sinus is located on either side of the pituitary gland.

      Understanding the location and function of these cranial venous sinuses is important for diagnosing and treating various neurological conditions.

    • This question is part of the following fields:

      • Neurological System
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  • Question 27 - A 70-year-old woman presents to the emergency department with confusion and drowsiness, discovered...

    Incorrect

    • A 70-year-old woman presents to the emergency department with confusion and drowsiness, discovered by her carers at home. She has experienced three episodes of vomiting and complains of a headache. Earlier in the day, she was unable to recognise her carers and is now communicating with short, nonsensical phrases.

      Based on her medical history of type 2 diabetes and stage 3 chronic kidney disease, along with the results of a CT head scan showing generalised cerebral and cerebellar oedema with narrowed ventricles and effaced sulci and cisterns, what is the most likely cause of this patient's symptoms?

      Your Answer: Hypophosphataemia

      Correct Answer: Hyponatraemia

      Explanation:

      Severe hyponatraemia can lead to cerebral oedema, which is likely the cause of the patient’s symptoms of confusion, headache, and drowsiness. The patient’s history of chronic kidney disease and use of thiazide diuretics increase her risk of developing hyponatraemia. Thiazides inhibit urinary dilution, leading to reduced reabsorption of NaCl in the distal renal tubules and an increased risk of hyponatraemia. In severe cases, hyponatraemia can cause a decrease in plasma osmolality, resulting in water movement into the brain and cerebral oedema.

      Hypocalcaemia is not associated with cerebral oedema and can be ruled out based on the CT findings. Hypomagnesaemia is typically asymptomatic unless severe and is not associated with cerebral oedema. Hypophosphataemia is uncommon in patients with renal disease and does not present with symptoms similar to those described in the vignette. Severe hypovolemia is not indicated in this case, as there is no evidence of reduced skin turgor, dry mucous membranes, reduced urine output, or other signs of hypovolaemic shock. However, it should be noted that rapid volume correction in hypovolaemic shock can also lead to cerebral oedema.

      Hyponatremia is a condition where the sodium levels in the blood are too low. If left untreated, it can lead to cerebral edema and brain herniation. Therefore, it is important to identify and treat hyponatremia promptly. The treatment plan depends on various factors such as the duration and severity of hyponatremia, symptoms, and the suspected cause. Over-rapid correction can lead to osmotic demyelination syndrome, which is a serious complication.

      Initial steps in treating hyponatremia involve ruling out any errors in the test results and reviewing medications that may cause hyponatremia. For chronic hyponatremia without severe symptoms, the treatment plan varies based on the suspected cause. If it is hypovolemic, normal saline may be given as a trial. If it is euvolemic, fluid restriction and medications such as demeclocycline or vaptans may be considered. If it is hypervolemic, fluid restriction and loop diuretics or vaptans may be considered.

      For acute hyponatremia with severe symptoms, patients require close monitoring in a hospital setting. Hypertonic saline is used to correct the sodium levels more quickly than in chronic cases. Vaptans, which act on V2 receptors, can be used but should be avoided in patients with hypovolemic hyponatremia and those with underlying liver disease.

      It is important to avoid over-correction of severe hyponatremia as it can lead to osmotic demyelination syndrome. Symptoms of this condition include dysarthria, dysphagia, paralysis, seizures, confusion, and coma. Therefore, sodium levels should only be raised by 4 to 6 mmol/L in a 24-hour period to prevent this complication.

    • This question is part of the following fields:

      • Renal System
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  • Question 28 - A 3-year-old child presents to their pediatrician with severe perianal itching that is...

    Correct

    • A 3-year-old child presents to their pediatrician with severe perianal itching that is particularly worse at night. The child has no known medical conditions and has been healthy up until this point. The birth history was unremarkable, and the child is up to date with their vaccinations. There have been no developmental concerns.

      After taking a thorough history, including asking about symptoms in other family members, the pediatrician uses the 'tape test' to make a diagnosis and prescribes appropriate treatment.

      What is the most probable cause of the child's pruritus in this scenario?

      Your Answer: Enterobius vermicularis infection

      Explanation:

      The most likely diagnosis for a 2-year-old child with perianal itching, especially at night, is Enterobius vermicularis infection, commonly known as pinworms. This is a common condition in young children and can cause discomfort and restlessness due to the itching around the anus.

      The diagnosis can be confirmed through the tape test, where adhesive tape is applied around the anus of the child upon waking and then examined under a microscope for the presence of worms or their eggs. While haemorrhoids can also cause peri-anal itching, they are not the most probable diagnosis in this case, especially given the age of the child.

      Echinococcus granulosus infection, which causes hydatid disease and cysts, is not a likely diagnosis for perianal itching. Perianal eczema is another possibility, but it would typically present with visible signs upon inspection, and the tape test would not be used for diagnosis.

      Helminths are a group of parasitic worms that can infect humans and cause various diseases. Nematodes, also known as roundworms, are one type of helminth. Strongyloides stercoralis is a type of roundworm that enters the body through the skin and can cause symptoms such as diarrhea, abdominal pain, and skin lesions. Treatment for this infection typically involves the use of ivermectin or benzimidazoles. Enterobius vermicularis, also known as pinworm, is another type of roundworm that can cause perianal itching and other symptoms. Diagnosis is made by examining sticky tape applied to the perianal area. Treatment typically involves benzimidazoles.

      Hookworms, such as Ancylostoma duodenale and Necator americanus, are another type of roundworm that can cause gastrointestinal infections and anemia. Treatment typically involves benzimidazoles. Loa loa is a type of roundworm that is transmitted by deer fly and mango fly and can cause red, itchy swellings called Calabar swellings. Treatment involves the use of diethylcarbamazine. Trichinella spiralis is a type of roundworm that can develop after eating raw pork and can cause fever, periorbital edema, and myositis. Treatment typically involves benzimidazoles.

      Onchocerca volvulus is a type of roundworm that causes river blindness and is spread by female blackflies. Treatment involves the use of ivermectin. Wuchereria bancrofti is another type of roundworm that is transmitted by female mosquitoes and can cause blockage of lymphatics and elephantiasis. Treatment involves the use of diethylcarbamazine. Toxocara canis, also known as dog roundworm, is transmitted through ingestion of infective eggs and can cause visceral larva migrans and retinal granulomas. Treatment involves the use of diethylcarbamazine. Ascaris lumbricoides, also known as giant roundworm, can cause intestinal obstruction and occasionally migrate to the lung. Treatment typically involves benzimidazoles.

      Cestodes, also known as tapeworms, are another type of helminth. Echinococcus granulosus is a tapeworm that is transmitted through ingestion of eggs in dog feces and can cause liver cysts and anaphylaxis if the cyst ruptures

    • This question is part of the following fields:

      • General Principles
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  • Question 29 - A 67-year-old woman presents to haematology with fevers, tiredness, and unexplained weight loss....

    Incorrect

    • A 67-year-old woman presents to haematology with fevers, tiredness, and unexplained weight loss. She has painless cervical lymphadenopathy on examination. The haematologist suspects follicular lymphoma and orders a lymph node biopsy to confirm the diagnosis. Which translocation is expected to be detected through cytogenetics?

      Your Answer: Translocation t(9;22)

      Correct Answer: Translocation t(14;18)

      Explanation:

      Genetics of Haematological Malignancies

      Haematological malignancies are cancers that affect the blood, bone marrow, and lymphatic system. These cancers are often associated with specific genetic abnormalities, such as translocations. Here are some common translocations and their associated haematological malignancies:

      – Philadelphia chromosome (t(9;22)): This translocation is present in more than 95% of patients with chronic myeloid leukaemia (CML). It results in the fusion of the Abelson proto-oncogene with the BCR gene on chromosome 22, creating the BCR-ABL gene. This gene codes for a fusion protein with excessive tyrosine kinase activity, which is a poor prognostic indicator in acute lymphoblastic leukaemia (ALL).

      – t(15;17): This translocation is seen in acute promyelocytic leukaemia (M3) and involves the fusion of the PML and RAR-alpha genes.

      – t(8;14): Burkitt’s lymphoma is associated with this translocation, which involves the translocation of the MYC oncogene to an immunoglobulin gene.

      – t(11;14): Mantle cell lymphoma is associated with the deregulation of the cyclin D1 (BCL-1) gene.

      – t(14;18): Follicular lymphoma is associated with increased BCL-2 transcription due to this translocation.

      Understanding the genetic abnormalities associated with haematological malignancies is important for diagnosis, prognosis, and treatment.

    • This question is part of the following fields:

      • Haematology And Oncology
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  • Question 30 - A couple is expecting a baby. The father has red-green colour blindness, but...

    Incorrect

    • A couple is expecting a baby. The father has red-green colour blindness, but the mother is unaffected. If they have a son, he will not inherit the disease. The doctor informs them that they are having a daughter.

      What is the likelihood that their daughter will be a carrier of the disease?

      Your Answer: 50%

      Correct Answer: 100%

      Explanation:

      What is the likelihood of a male child from these parents being affected by red-green color blindness? The father has a mutated X chromosome but will pass on his Y chromosome to his son, which does not carry the disease. The mother does not have the condition, so the son will inherit a non-mutated X chromosome from her.

      X-linked recessive inheritance affects only males, except in cases of Turner’s syndrome where females are affected due to having only one X chromosome. This type of inheritance is transmitted by carrier females, and male-to-male transmission is not observed. Affected males can only have unaffected sons and carrier daughters.

      If a female carrier has children, each male child has a 50% chance of being affected, while each female child has a 50% chance of being a carrier. It is rare for an affected father to have children with a heterozygous female carrier, but in some Afro-Caribbean communities, G6PD deficiency is relatively common, and homozygous females with clinical manifestations of the enzyme defect can be seen.

    • This question is part of the following fields:

      • General Principles
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SESSION STATS - PERFORMANCE PER SPECIALTY

Renal System (2/4) 50%
Musculoskeletal System And Skin (0/1) 0%
General Principles (8/12) 67%
Neurological System (2/4) 50%
Cardiovascular System (3/3) 100%
Gastrointestinal System (0/1) 0%
Haematology And Oncology (1/3) 33%
Psychiatry (1/1) 100%
Reproductive System (0/1) 0%
Passmed