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Question 1
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A 35-year-old woman is referred to the endocrine clinic due to missed periods and lactation. She has also gained weight and experiences vaginal dryness. The endocrinologist decides to measure her prolactin levels. What hormone is responsible for suppressing the release of prolactin from the pituitary gland?
Your Answer: Dopamine
Explanation:Dopamine consistently prevents the release of prolactin.
Understanding Prolactin and Its Functions
Prolactin is a hormone that is produced by the anterior pituitary gland. Its primary function is to stimulate breast development and milk production in females. During pregnancy, prolactin levels increase to support the growth and development of the mammary glands. It also plays a role in reducing the pulsatility of gonadotropin-releasing hormone (GnRH) at the hypothalamic level, which can block the action of luteinizing hormone (LH) on the ovaries or testes.
The secretion of prolactin is regulated by dopamine, which constantly inhibits its release. However, certain factors can increase or decrease prolactin secretion. For example, prolactin levels increase during pregnancy, in response to estrogen, and during breastfeeding. Additionally, stress, sleep, and certain drugs like metoclopramide and antipsychotics can also increase prolactin secretion. On the other hand, dopamine and dopaminergic agonists can decrease prolactin secretion.
Overall, understanding the functions and regulation of prolactin is important for reproductive health and lactation.
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This question is part of the following fields:
- Endocrine System
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Question 2
Incorrect
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A 75-year-old man has recently been diagnosed with chronic myeloid leukaemia and is undergoing chemotherapy. Following the start of treatment, he experiences acute renal failure and a significant increase in uric acid levels. What other electrolyte abnormality is likely to be present?
Your Answer: Hypokalaemia
Correct Answer: Hyperphosphataemia
Explanation:The individual has been diagnosed with tumour lysis syndrome, which is a dangerous complication that can arise when commencing chemotherapy for cancer, particularly for lymphoma and leukaemia. Tumour lysis syndrome encompasses a range of metabolic imbalances, such as elevated levels of potassium, phosphates, and uric acid, as well as reduced levels of calcium. These imbalances can result in severe complications, including acute kidney failure, irregular heartbeats, and seizures.
Understanding Tumour Lysis Syndrome
Tumour lysis syndrome (TLS) is a life-threatening condition that can occur during the treatment of high-grade lymphomas and leukaemias. It is caused by the breakdown of tumour cells and the release of chemicals into the bloodstream. While it can occur without chemotherapy, it is usually triggered by the introduction of combination chemotherapy. Patients at high risk of TLS should be given prophylactic medication such as IV allopurinol or IV rasburicase to prevent the potentially deadly effects of tumour cell lysis.
TLS leads to a high potassium and high phosphate level in the presence of a low calcium. It should be suspected in any patient presenting with an acute kidney injury in the presence of a high phosphate and high uric acid level. From 2004, TLS has been graded using the Cairo-Bishop scoring system, which takes into account laboratory and clinical factors.
It is important to be aware of TLS and take preventative measures to avoid its potentially fatal consequences. By understanding the causes and symptoms of TLS, healthcare professionals can provide appropriate treatment and improve patient outcomes.
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This question is part of the following fields:
- Haematology And Oncology
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Question 3
Correct
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A 32-year-old male patient visits the surgical clinic after 8 months of undergoing laparotomy for a ruptured spleen. He reports a lump in the middle of his laparotomy wound. Upon surgical exploration, a stitch granuloma is discovered and removed. What is the origin of granulomas in the body?
Your Answer: Macrophages
Explanation:Organised collections of macrophages are known as granulomas.
Chronic inflammation can occur as a result of acute inflammation or as a primary process. There are three main processes that can lead to chronic inflammation: persisting infection with certain organisms, prolonged exposure to non-biodegradable substances, and autoimmune conditions involving antibodies formed against host antigens. Acute inflammation involves changes to existing vascular structure and increased permeability of endothelial cells, as well as infiltration of neutrophils. In contrast, chronic inflammation is characterized by angiogenesis and the predominance of macrophages, plasma cells, and lymphocytes. The process may resolve with suppuration, complete resolution, abscess formation, or progression to chronic inflammation. Healing by fibrosis is the main result of chronic inflammation. Granulomas, which consist of a microscopic aggregation of macrophages, are pathognomonic of chronic inflammation and can be found in conditions such as colonic Crohn’s disease. Growth factors released by activated macrophages, such as interferon and fibroblast growth factor, may have systemic features resulting in systemic symptoms and signs in individuals with long-standing chronic inflammation.
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This question is part of the following fields:
- Haematology And Oncology
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Question 4
Incorrect
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A 70-year-old man visits his GP with a persistent ulcer in his buccal mucosa. He has experienced a weight loss of 1 stone in the past 3 months and has a smoking history of 40 pack-years. The GP is worried and decides to refer him to the urgent 2-week pathway. Can you identify the virus that is a recognized risk factor for the development of this condition?
Your Answer: Human herpes virus 8
Correct Answer: Human papillomavirus 16/18
Explanation:Oropharyngeal cancer is often associated with human papillomavirus 16/18 as a risk factor. The presence of persistent ulcers, a history of smoking, and weight loss are all concerning symptoms. The virus can infect cells in the oropharynx and cause cellular changes that may lead to cancer if left untreated.
Human herpes virus 6 is not typically linked to cancer. Instead, it is commonly associated with roseola infantum, a condition characterized by a high fever and rash in young children.
On the other hand, human herpes virus 8 is known to be associated with Kaposi’s sarcoma, a type of cancer that usually affects immunocompromised individuals. This cancer is characterized by pink or purple plaques on the skin, mouth, and sometimes internal organs.
Understanding Oncoviruses and Their Associated Cancers
Oncoviruses are viruses that have the potential to cause cancer. These viruses can be detected through blood tests and prevented through vaccination. There are several types of oncoviruses, each associated with a specific type of cancer.
The Epstein-Barr virus, for example, is linked to Burkitt’s lymphoma, Hodgkin’s lymphoma, post-transplant lymphoma, and nasopharyngeal carcinoma. Human papillomavirus 16/18 is associated with cervical cancer, anal cancer, penile cancer, vulval cancer, and oropharyngeal cancer. Human herpes virus 8 is linked to Kaposi’s sarcoma, while hepatitis B and C viruses are associated with hepatocellular carcinoma. Finally, human T-lymphotropic virus 1 is linked to tropical spastic paraparesis and adult T cell leukemia.
It is important to understand the link between oncoviruses and cancer so that appropriate measures can be taken to prevent and treat these diseases. Vaccination against certain oncoviruses, such as HPV, can significantly reduce the risk of developing associated cancers. Regular screening and early detection can also improve outcomes for those who do develop cancer as a result of an oncovirus.
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This question is part of the following fields:
- General Principles
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Question 5
Incorrect
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You are working in a GP clinic. A 32-year-old woman has multiple sclerosis. After taking a history and examining her, you diagnose her with chronic urinary retention.
What nerves are most likely affected by demyelination in this case?Your Answer: Hypogastric
Correct Answer: Pelvic splanchnic
Explanation:The pelvic splanchnic nerves provide parasympathetic innervation to the bladder. In cases of chronic urinary retention, damage to these nerves may be the cause. The greater splanchnic nerves supply the foregut of the gastrointestinal tract, while the lesser splanchnic nerves supply the midgut. Sympathetic innervation of the bladder comes from the hypogastric nerve plexuses, and the lumbar splanchnic nerves innervate the smooth muscles and glands of the pelvis.
Bladder Anatomy and Innervation
The bladder is a three-sided pyramid-shaped organ located in the pelvic cavity. Its apex points towards the symphysis pubis, while the base lies anterior to the rectum or vagina. The bladder’s inferior aspect is retroperitoneal, while the superior aspect is covered by peritoneum. The trigone, the least mobile part of the bladder, contains the ureteric orifices and internal urethral orifice. The bladder’s blood supply comes from the superior and inferior vesical arteries, while venous drainage occurs through the vesicoprostatic or vesicouterine venous plexus. Lymphatic drainage occurs mainly to the external iliac and internal iliac nodes, with the obturator nodes also playing a role. The bladder is innervated by parasympathetic nerve fibers from the pelvic splanchnic nerves and sympathetic nerve fibers from L1 and L2 via the hypogastric nerve plexuses. The parasympathetic fibers cause detrusor muscle contraction, while the sympathetic fibers innervate the trigone muscle. The external urethral sphincter is under conscious control, and voiding occurs when the rate of neuronal firing to the detrusor muscle increases.
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This question is part of the following fields:
- Renal System
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Question 6
Incorrect
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A 20-year-old man is admitted to the emergency department after being stabbed in the back. The knife has penetrated his spinal column at a perpendicular angle, causing damage to the termination of his spinal cord.
Which spinal level has been affected by the knife's penetration?Your Answer: L3
Correct Answer: L1
Explanation:In adults, the level of L1 is where the spinal cord usually ends.
Lumbar Puncture Procedure
Lumbar puncture is a medical procedure that involves obtaining cerebrospinal fluid. In adults, the procedure is typically performed at the L3/L4 or L4/5 interspace, which is located below the spinal cord’s terminates at L1.
During the procedure, the needle passes through several layers. First, it penetrates the supraspinous ligament, which connects the tips of spinous processes. Then, it passes through the interspinous ligaments between adjacent borders of spinous processes. Next, the needle penetrates the ligamentum flavum, which may cause a give. Finally, the needle passes through the dura mater into the subarachnoid space, which is marked by a second give. At this point, clear cerebrospinal fluid should be obtained.
Overall, the lumbar puncture procedure is a complex process that requires careful attention to detail. By following the proper steps and guidelines, medical professionals can obtain cerebrospinal fluid safely and effectively.
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This question is part of the following fields:
- Neurological System
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Question 7
Incorrect
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What is the process by which B cells can produce epitope-specific antibodies with extremely high affinity through random mutations of their existing receptors?
Your Answer: Positive selection
Correct Answer: Somatic hypermutation
Explanation:The Process of B Cell Activation and Germinal Center Formation
When an antigen activates a naïve B cell and receives appropriate signals from a Th2 CD4+ T cell, the B cell undergoes proliferation and gene mutation to form a germinal center. This process involves the formation of B-blasts and centroblasts, which insert new mutations into the variable regions of the light- and heavy-chain loci of their existing B cell receptor (BCR) through somatic hypermutation. This allows the production of a new BCR based on a receptor that is already known to bind antigen. The new BCRs are then tested against antigen by follicular dendritic cells to find a BCR with higher affinity.
Simultaneously, class switching occurs, which refers to the exchange of heavy chain constant domain to move from IgM to any other Ig class. In the production of naïve lymphocytes in the thymus, negative and positive selection are involved. Somatic gene segment recombination is the process that allows the production of a random T cell or B cell receptor when cells are made in the bone marrow.
Overall, the process of B cell activation and germinal center formation is a complex and intricate process that involves multiple steps and mechanisms. However, it is essential for the production of high-affinity antibodies and the development of an effective immune response.
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This question is part of the following fields:
- Clinical Sciences
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Question 8
Incorrect
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A 28-year-old man has a glomerular filtration rate of 110ml / minute at a systolic blood pressure of 120/80. If his blood pressure were to decrease to 100/70, what would be his glomerular filtration rate?
Your Answer: 100 ml/ minute
Correct Answer: 110ml / minute
Explanation:The suggested decrease in blood pressure is within the kidney’s autoregulatory range for blood supply, so the GFR will remain unaffected.
The Loop of Henle and its Role in Renal Physiology
The Loop of Henle is a crucial component of the renal system, located in the juxtamedullary nephrons and running deep into the medulla. Approximately 60 litres of water containing 9000 mmol sodium enters the descending limb of the loop of Henle in 24 hours. The osmolarity of fluid changes and is greatest at the tip of the papilla. The thin ascending limb is impermeable to water, but highly permeable to sodium and chloride ions. This loss means that at the beginning of the thick ascending limb the fluid is hypo osmotic compared with adjacent interstitial fluid. In the thick ascending limb, the reabsorption of sodium and chloride ions occurs by both facilitated and passive diffusion pathways. The loops of Henle are co-located with vasa recta, which have similar solute compositions to the surrounding extracellular fluid, preventing the diffusion and subsequent removal of this hypertonic fluid. The energy-dependent reabsorption of sodium and chloride in the thick ascending limb helps to maintain this osmotic gradient. Overall, the Loop of Henle plays a crucial role in regulating the concentration of solutes in the renal system.
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This question is part of the following fields:
- Renal System
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Question 9
Incorrect
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A 38-year-old woman presents at the outpatient clinic after a routine surgery and reports reduced sensation on the dorso-lateral aspect of her foot. Which nerve is the most probable cause of this issue?
Your Answer: Deep peroneal
Correct Answer: Sural
Explanation:The lateral aspect of the foot is innervated by the sural nerve, which travels parallel to the short saphenous vein. During surgery on the short saphenous vein, there is a risk of damaging the sural nerve.
Cutaneous Sensation in the Foot
Cutaneous sensation in the foot is the ability to feel touch, pressure, temperature, and pain on the skin of the foot. Different regions of the foot are innervated by different nerves, which are responsible for transmitting sensory information to the brain. The lateral plantar region is innervated by the sural nerve, while the dorsum (excluding the 1st web space) is innervated by the superficial peroneal nerve. The 1st web space is innervated by the deep peroneal nerve, and the extremities of the toes are innervated by the medial and lateral plantar nerves. The proximal plantar region is innervated by the tibial nerve, while the medial plantar region is innervated by the medial plantar nerve and the lateral plantar region is innervated by the lateral plantar nerve. Understanding the innervation of the foot is important for diagnosing and treating conditions that affect cutaneous sensation in this area.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 10
Incorrect
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A 68-year-old man comes to your clinic with a painful, swollen, and red cheek. During the examination, you notice an erythematous swelling above the mandible's angle on the left side. The swelling is warm and tender to the touch. The patient had a stroke eight weeks ago and has had difficulty swallowing since then. He is currently being fed through a percutaneous enteral gastrostomy tube, which has been in place for six weeks. You suspect that he has a parotid gland infection. What is the artery that passes through the parotid gland and usually bifurcates within it?
Your Answer: Lingual artery
Correct Answer: External carotid artery
Explanation:The external carotid artery runs through the parotid gland and divides into the superficial temporal artery and the maxillary artery. It gives rise to several branches, including the facial artery, superior thyroid artery, and lingual artery, which supply various structures in the face, thyroid gland, and tongue.
The internal carotid artery is one of the two main branches of the common carotid artery and supplies a significant portion of the brain and surrounding structures. Patients who have had strokes may experience dysphagia, which increases the risk of aspiration and may require feeding through a nasogastric tube or percutaneous enteral gastrostomy (PEG). Long-term PEG feeding may increase the risk of infective parotitis.
Anatomy of the External Carotid Artery
The external carotid artery begins on the side of the pharynx and runs in front of the internal carotid artery, behind the posterior belly of digastric and stylohyoid muscles. It is covered by sternocleidomastoid muscle and passed by hypoglossal nerves, lingual and facial veins. The artery then enters the parotid gland and divides into its terminal branches within the gland.
To locate the external carotid artery, an imaginary line can be drawn from the bifurcation of the common carotid artery behind the angle of the jaw to a point in front of the tragus of the ear.
The external carotid artery has six branches, with three in front, two behind, and one deep. The three branches in front are the superior thyroid, lingual, and facial arteries. The two branches behind are the occipital and posterior auricular arteries. The deep branch is the ascending pharyngeal artery. The external carotid artery terminates by dividing into the superficial temporal and maxillary arteries within the parotid gland.
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This question is part of the following fields:
- Cardiovascular System
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Question 11
Incorrect
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A 9-month-old baby girl is brought to the clinic by her parents who recently moved from the Philippines. The baby has a noticeable mass in her abdomen, resembling a sausage shape. During questioning, the father mentions that the baby had vomited green substance a few hours ago. The baby is immediately referred to the hospital. What is the probable diagnosis?
Your Answer: Kernicterus
Correct Answer: Intussusception
Explanation:Understanding Intussusception
Intussusception is a medical condition where one part of the bowel folds into the lumen of the adjacent bowel, usually around the ileocecal region. This condition is most common in infants between 6-18 months old, with boys being affected twice as often as girls. Symptoms of intussusception include severe, crampy abdominal pain, inconsolable crying, vomiting, and bloodstained stool, which is a late sign. During a paroxysm, the infant will draw their knees up and turn pale, and a sausage-shaped mass may be felt in the right upper quadrant.
To diagnose intussusception, ultrasound is now the preferred method of investigation, which may show a target-like mass. Treatment for intussusception involves reducing the bowel by air insufflation under radiological control, which is now widely used first-line compared to the traditional barium enema. If this method fails, or the child has signs of peritonitis, surgery is performed. Understanding the symptoms and treatment options for intussusception is crucial for parents and healthcare professionals to ensure prompt and effective management of this condition.
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This question is part of the following fields:
- Gastrointestinal System
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Question 12
Incorrect
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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.
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This question is part of the following fields:
- General Principles
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Question 13
Incorrect
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A senior woman with a history of chronic obstructive pulmonary disease (COPD) arrives at the hospital complaining of worsening shortness of breath and a productive cough. As part of the initial evaluation, a chest X-ray is requested.
What radiographic feature would you anticipate observing on her chest X-ray?Your Answer: Empyema
Correct Answer: Flattened diaphragm
Explanation:The diaphragm of patients with COPD often appears flattened on a chest X-ray due to the chronic expiratory airflow obstruction causing dynamic hyperinflation of the lungs. Pleural effusions are commonly associated with infection, malignancy, or heart failure, while empyema is a result of pus accumulation in the pleural space caused by an infection.
Understanding COPD: Symptoms and Diagnosis
Chronic obstructive pulmonary disease (COPD) is a common medical condition that includes chronic bronchitis and emphysema. Smoking is the leading cause of COPD, and patients with mild disease may only need occasional use of a bronchodilator, while severe cases may result in frequent hospital admissions due to exacerbations. Symptoms of COPD include a productive cough, dyspnea, wheezing, and in severe cases, right-sided heart failure leading to peripheral edema.
To diagnose COPD, doctors may recommend post-bronchodilator spirometry to demonstrate airflow obstruction, a chest x-ray to check for hyperinflation, bullae, and flat hemidiaphragm, and to exclude lung cancer. A full blood count may also be necessary to exclude secondary polycythemia, and body mass index (BMI) calculation is important. The severity of COPD is categorized using the FEV1, with a ratio of less than 70% indicating airflow obstruction. The grading system has changed following the 2010 NICE guidelines, with Stage 1 – mild now including patients with an FEV1 greater than 80% predicted but with a post-bronchodilator FEV1/FVC ratio of less than 0.7. Measuring peak expiratory flow is of limited value in COPD, as it may underestimate the degree of airflow obstruction.
In summary, COPD is a common condition caused by smoking that can result in a range of symptoms and severity. Diagnosis involves various tests to check for airflow obstruction, exclude lung cancer, and determine the severity of the disease.
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This question is part of the following fields:
- Respiratory System
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Question 14
Incorrect
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A 23 years old male presents to his GP with a complaint of inability to flex his left elbow. During examination, the GP observes significant weakness in flexion of his left elbow and supination of his forearm. Which nerve is most likely to be damaged in this case?
Your Answer: Median nerve
Correct Answer: Musculocutaneous nerve
Explanation:The musculocutaneous nerve provides innervation to the Bicep, Brachialis, and Coracobrachialis muscles in the upper arm, which are responsible for elbow flexion and forearm supination. If a patient has weak elbow flexion and supination, it may indicate damage to the musculocutaneous nerve. The radial nerve innervates the tricep brachii and extensor muscles in the forearm, while the median nerve is responsible for the anterior compartment of the forearm and does not innervate any arm muscles. The ulnar nerve innervates two forearm muscles and intrinsic hand muscles, excluding the thenar muscles and two lateral lumbricals.
Upper limb anatomy is a common topic in examinations, and it is important to know certain facts about the nerves and muscles involved. The musculocutaneous nerve is responsible for elbow flexion and supination, and typically only injured as part of a brachial plexus injury. The axillary nerve controls shoulder abduction and can be damaged in cases of humeral neck fracture or dislocation, resulting in a flattened deltoid. The radial nerve is responsible for extension in the forearm, wrist, fingers, and thumb, and can be damaged in cases of humeral midshaft fracture, resulting in wrist drop. The median nerve controls the LOAF muscles and can be damaged in cases of carpal tunnel syndrome or elbow injury. The ulnar nerve controls wrist flexion and can be damaged in cases of medial epicondyle fracture, resulting in a claw hand. The long thoracic nerve controls the serratus anterior and can be damaged during sports or as a complication of mastectomy, resulting in a winged scapula. The brachial plexus can also be damaged, resulting in Erb-Duchenne palsy or Klumpke injury, which can cause the arm to hang by the side and be internally rotated or associated with Horner’s syndrome, respectively.
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This question is part of the following fields:
- Musculoskeletal System And Skin
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Question 15
Incorrect
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A 65-year-old woman has been diagnosed with endometrial carcinoma originating from the uterine body. Which nodal region will the tumor spread to first?
Your Answer: Para aortic nodes
Correct Answer: Iliac lymph nodes
Explanation:In the case of uterine body tumours, the initial spread is likely to occur in the iliac nodes. This becomes clinically significant when nodal clearance is carried out during a Wertheims type hysterectomy, as the tumour may cross different nodal margins.
Lymphatic Drainage of Female Reproductive Organs
The lymphatic drainage of the female reproductive organs is a complex system that involves multiple nodal stations. The ovaries drain to the para-aortic lymphatics via the gonadal vessels. The uterine fundus has a lymphatic drainage that runs with the ovarian vessels and may thus drain to the para-aortic nodes. Some drainage may also pass along the round ligament to the inguinal nodes. The body of the uterus drains through lymphatics contained within the broad ligament to the iliac lymph nodes. The cervix drains into three potential nodal stations; laterally through the broad ligament to the external iliac nodes, along the lymphatics of the uterosacral fold to the presacral nodes and posterolaterally along lymphatics lying alongside the uterine vessels to the internal iliac nodes. Understanding the lymphatic drainage of the female reproductive organs is important for the diagnosis and treatment of gynecological cancers.
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This question is part of the following fields:
- Haematology And Oncology
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Question 16
Incorrect
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A 44-year-old man with active hepatitis B infection is found to have transitional cell carcinoma of the bladder. After a multidisciplinary assessment, it is determined that his cancer is a non-muscle-invasive tumour of intermediate risk. He undergoes a successful transurethral resection of the carcinoma. However, due to his high risk of recurrence, he is being considered for postoperative intravesical chemotherapy or intravesical bacillus Calmette-Guérin (BCG).
Despite having a BCG vaccination scar on his shoulder, he was treated for pulmonary tuberculosis 22 years ago. He has been on antiretroviral therapy for HIV for the past six years.
What is the factor in this patient's medical history that makes intravesical BCG administration contraindicated?Your Answer: Papillary carcinoma
Correct Answer: HIV positive
Explanation:BCG vaccine cannot be given to individuals who have compromised immune systems, such as those with HIV infection, as it is a live vaccine. It is also contraindicated in pregnant women and those with existing tuberculosis infection. Intravesical BCG is not recommended for individuals with active urinary tract infection, traumatic catheterisation, gross haematuria, or recent bladder surgery. However, having hepatitis B or previous BCG vaccination does not prevent an individual from receiving the BCG vaccine. Additionally, intravesical BCG is indicated for reducing the risk of recurrence in non-muscle-invasive papillary carcinoma cases.
The BCG vaccine is a form of immunization that provides limited protection against tuberculosis (TB). In the UK, it is typically given to high-risk infants and was previously administered to children at the age of 13 years until 2005. The Greenbook recommends that the vaccine be given to infants living in areas with an annual incidence of TB of 40/100,000 or greater, as well as infants with a parent or grandparent born in a country with a similar incidence rate. Other groups that should receive the vaccine include previously unvaccinated contacts of respiratory TB cases, healthcare workers, prison staff, and those who work with homeless people.
The vaccine contains live attenuated Mycobacterium bovis and also offers limited protection against leprosy. Before receiving the BCG vaccine, individuals must undergo a tuberculin skin test, with the exception of children under six years old who have had no contact with tuberculosis. The vaccine is administered intradermally to the lateral aspect of the left upper arm and can be given at the same time as other live vaccines, with a four-week interval if not administered simultaneously.
There are several contraindications for the BCG vaccine, including previous vaccination, a history of tuberculosis, HIV, pregnancy, and a positive tuberculin test. It is not recommended for individuals over the age of 35, as there is no evidence that it is effective for this age group.
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This question is part of the following fields:
- General Principles
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Question 17
Incorrect
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A 44-year-old man has been diagnosed with type II diabetes mellitus but cannot tolerate metformin therapy. What is the mechanism of action of alogliptin, which has been prescribed as an alternative?
Your Answer: Increases production of glucagon-like-peptide-1
Correct Answer: Reduce the peripheral breakdown of incretins
Explanation:Gliptins (DPP-4 inhibitors) work by inhibiting the enzyme DPP-4, which reduces the breakdown of incretin hormones such as GLP-1. This leads to a glucose-dependent increase in insulin secretion and a reduction in glucagon secretion, ultimately regulating glucose homeostasis. However, gliptins do not increase the production of GLP-1, directly stimulate the release of insulin from pancreatic beta cells, inhibit the SGLT2 receptor, or reduce insulin resistance.
Diabetes mellitus is a condition that has seen the development of several drugs in recent years. One hormone that has been the focus of much research is glucagon-like peptide-1 (GLP-1), which is released by the small intestine in response to an oral glucose load. In type 2 diabetes mellitus (T2DM), insulin resistance and insufficient B-cell compensation occur, and the incretin effect, which is largely mediated by GLP-1, is decreased. GLP-1 mimetics, such as exenatide and liraglutide, increase insulin secretion and inhibit glucagon secretion, resulting in weight loss, unlike other medications. They are sometimes used in combination with insulin in T2DM to minimize weight gain. Dipeptidyl peptidase-4 (DPP-4) inhibitors, such as vildagliptin and sitagliptin, increase levels of incretins by decreasing their peripheral breakdown, are taken orally, and do not cause weight gain. Nausea and vomiting are the major adverse effects of GLP-1 mimetics, and the Medicines and Healthcare products Regulatory Agency has issued specific warnings on the use of exenatide, reporting that it has been linked to severe pancreatitis in some patients. NICE guidelines suggest that a DPP-4 inhibitor might be preferable to a thiazolidinedione if further weight gain would cause significant problems, a thiazolidinedione is contraindicated, or the person has had a poor response to a thiazolidinedione.
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This question is part of the following fields:
- Endocrine System
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Question 18
Incorrect
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An anxious father brings his 6-month-old to the out of hours GP. The baby has been coughing persistently for the past 2 days and it seems to be getting worse. He also has a runny nose and an audible wheeze. The GP diagnoses bronchiolitis.
What is the most probable causative organism in this case?Your Answer: Haemophilus influenzae B
Correct Answer: Respiratory syncytial virus
Explanation:Understanding Bronchiolitis
Bronchiolitis is a condition that is characterized by inflammation of the bronchioles. It is a serious lower respiratory tract infection that is most common in children under the age of one year. The pathogen responsible for 75-80% of cases is respiratory syncytial virus (RSV), while other causes include mycoplasma and adenoviruses. Bronchiolitis is more serious in children with bronchopulmonary dysplasia, congenital heart disease, or cystic fibrosis.
The symptoms of bronchiolitis include coryzal symptoms, dry cough, increasing breathlessness, and wheezing. Fine inspiratory crackles may also be present. Children with bronchiolitis may experience feeding difficulties associated with increasing dyspnoea, which is often the reason for hospital admission.
Immediate referral to hospital is recommended if the child has apnoea, looks seriously unwell to a healthcare professional, has severe respiratory distress, central cyanosis, or persistent oxygen saturation of less than 92% when breathing air. Clinicians should consider referring to hospital if the child has a respiratory rate of over 60 breaths/minute, difficulty with breastfeeding or inadequate oral fluid intake, or clinical dehydration.
The investigation for bronchiolitis involves immunofluorescence of nasopharyngeal secretions, which may show RSV. Management of bronchiolitis is largely supportive, with humidified oxygen given via a head box if oxygen saturations are persistently < 92%. Nasogastric feeding may be needed if children cannot take enough fluid/feed by mouth, and suction is sometimes used for excessive upper airway secretions.
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This question is part of the following fields:
- Respiratory System
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Question 19
Incorrect
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An 85-year-old woman presents to the emergency department with a recent onset of confusion. Her daughter reports that she had a fall at home last month and hit her head but did not seek medical attention as she appeared to be fine. A CT scan of her head reveals a hyper-dense crescent-shaped area in the left hemisphere. What is the likely diagnosis, and between which meningeal layers is the blood collecting?
Your Answer: Subarachnoid space
Correct Answer: Arachnoid mater
Explanation:The middle layer of the meninges is called the arachnoid mater. In an elderly patient with a history like the one described, a subacute subdural hematoma is likely the cause. This occurs when blood collects in the space between the dura mater and arachnoid mater. The arachnoid mater is a very thin layer that is attached to the inside of the dura mater and separated from the innermost layer (pia mater) by the subarachnoid space. Acromion and bone are incorrect answers as they are not related to the meninges, and pia mater is incorrect because it is the innermost layer of the meninges that is attached to the brain and spinal cord.
The Three Layers of Meninges
The meninges are a group of membranes that cover the brain and spinal cord, providing support to the central nervous system and the blood vessels that supply it. These membranes can be divided into three distinct layers: the dura mater, arachnoid mater, and pia mater.
The outermost layer, the dura mater, is a thick fibrous double layer that is fused with the inner layer of the periosteum of the skull. It has four areas of infolding and is pierced by small areas of the underlying arachnoid to form structures called arachnoid granulations. The arachnoid mater forms a meshwork layer over the surface of the brain and spinal cord, containing both cerebrospinal fluid and vessels supplying the nervous system. The final layer, the pia mater, is a thin layer attached directly to the surface of the brain and spinal cord.
The meninges play a crucial role in protecting the brain and spinal cord from injury and disease. However, they can also be the site of serious medical conditions such as subdural and subarachnoid haemorrhages. Understanding the structure and function of the meninges is essential for diagnosing and treating these conditions.
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This question is part of the following fields:
- Neurological System
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Question 20
Incorrect
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A 57-year-old woman came to the breast clinic with a breast lump. During the examination, a non-tender, irregular, 3 cm lump was palpated in the left upper quadrant. The diagnosis was ductal carcinoma in situ of the left breast. The oncology team was consulted, and the patient was started on anastrozole.
What is the mechanism of action of this medication?Your Answer: Oestrogen receptor antagonist
Correct Answer: Reduces peripheral oestrogen synthesis
Explanation:Anastrozole and letrozole are medications that inhibit the production of oestrogen in peripheral tissues through the enzyme aromatase. These drugs are commonly used to treat breast cancer in postmenopausal women.
Trastuzumab is a monoclonal antibody that targets HER2 receptors on cancer cells, inhibiting their growth and proliferation. It is effective in treating HER2-positive breast cancer.
Fulvestrant is a selective oestrogen receptor degrader that breaks down oestrogen receptors without activating them, unlike tamoxifen. This leads to downregulation of the receptor.
Goserelin is an LHRH agonist that suppresses oestrogen production by the ovaries. It is often used as adjuvant therapy in premenopausal women.
Tamoxifen is an antagonist (and partial agonist) of the oestrogen receptor. It is particularly useful in treating oestrogen-receptor positive breast cancer, especially in patients who have not yet gone through menopause.
Anti-oestrogen drugs are used in the management of oestrogen receptor-positive breast cancer. Selective oEstrogen Receptor Modulators (SERM) such as Tamoxifen act as an oestrogen receptor antagonist and partial agonist. However, Tamoxifen may cause adverse effects such as menstrual disturbance, hot flushes, venous thromboembolism, and endometrial cancer. On the other hand, aromatase inhibitors like Anastrozole and Letrozole reduce peripheral oestrogen synthesis, which is important in postmenopausal women. Anastrozole is used for ER +ve breast cancer in this group. However, aromatase inhibitors may cause adverse effects such as osteoporosis, hot flushes, arthralgia, myalgia, and insomnia. NICE recommends a DEXA scan when initiating a patient on aromatase inhibitors for breast cancer.
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This question is part of the following fields:
- Reproductive System
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