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  • Question 1 - A 32-year-old man who is HIV-positive comes in for a medication review. During...

    Correct

    • A 32-year-old man who is HIV-positive comes in for a medication review. During the discussion of his prescribed drugs, you observe that he is taking an integrase inhibitor, which functions by obstructing the enzyme integrase. This enzyme is responsible for inserting viral genetic material into human genomes.

      Which specific medication is he likely taking?

      Your Answer: Raltegravir

      Explanation:

      Integrase inhibitors, also known as ‘gravirs’, block the enzyme responsible for inserting the viral genome into the DNA of the host cell. Raltegravir is an example of a drug with this mechanism of action, and other drugs with the suffix ‘-gravir’ also function as integrase inhibitors. By preventing HIV viral information from integrating into host DNA, these drugs effectively halt further replication of HIV virions. It is important to note that Maraviroc, Nevirapine, and Rifampicin are not integrase inhibitors and do not function in the same way as ‘gravirs’.

      Antiretroviral therapy (ART) is a treatment for HIV that involves a combination of at least three drugs. This combination typically includes two nucleoside reverse transcriptase inhibitors (NRTI) and either a protease inhibitor (PI) or a non-nucleoside reverse transcriptase inhibitor (NNRTI). ART reduces viral replication and the risk of viral resistance emerging. The 2015 BHIVA guidelines recommend that patients start ART as soon as they are diagnosed with HIV, rather than waiting until a particular CD4 count.

      Entry inhibitors, such as maraviroc and enfuvirtide, prevent HIV-1 from entering and infecting immune cells. Nucleoside analogue reverse transcriptase inhibitors (NRTI), such as zidovudine, abacavir, and tenofovir, can cause peripheral neuropathy and other side effects. Non-nucleoside reverse transcriptase inhibitors (NNRTI), such as nevirapine and efavirenz, can cause P450 enzyme interaction and rashes. Protease inhibitors (PI), such as indinavir and ritonavir, can cause diabetes, hyperlipidaemia, and other side effects. Integrase inhibitors, such as raltegravir and dolutegravir, block the action of integrase, a viral enzyme that inserts the viral genome into the DNA of the host cell.

    • This question is part of the following fields:

      • General Principles
      47.5
      Seconds
  • Question 2 - A glazier in his 40s slipped and cut his wrist on a piece...

    Correct

    • A glazier in his 40s slipped and cut his wrist on a piece of glass a few months ago. He did not seek medical advice at the time.

      What signs of ulnar nerve damage would you expect to find on examination?

      Your Answer: Wasting of the interossei

      Explanation:

      Lesion of the Ulnar Nerve at the Wrist

      A lesion of the ulnar nerve at the wrist does not result in sensory loss as the dorsal cutaneous branch of the ulnar nerve remains unaffected. Additionally, the flexor carpi ulnaris muscle is also spared, which means that wrist flexion is not affected. However, wasting and weakness are limited to the interossei and adductor pollicis muscle, while the hypothenar muscles are usually spared.

      It is important to note that sensory loss of the lateral part of the hand occurs in a median nerve injury, while sensory loss of the dorsal surface of the thumb occurs in a radial nerve injury. Furthermore, weakness of wrist flexion occurs when the ulnar or median nerve is damaged, but not at the wrist. these distinctions can aid in the diagnosis and treatment of nerve injuries.

    • This question is part of the following fields:

      • Clinical Sciences
      55.3
      Seconds
  • Question 3 - A 10-year-old girl arrives at the emergency department with her father. She complains...

    Correct

    • A 10-year-old girl arrives at the emergency department with her father. She complains of a headache followed by seeing flashing lights and floaters. Her father also noticed her eyes moving from side to side. What type of seizure is likely to be associated with these symptoms?

      Your Answer: Occipital lobe seizure

      Explanation:

      Visual changes like floaters and flashes are common symptoms of occipital lobe seizures, while hallucinations and automatisms are associated with temporal lobe seizures. Head and leg movements, as well as postictal weakness, are typical of frontal lobe seizures, while paraesthesia is a common symptom of parietal lobe seizures.

      Localising Features of Focal Seizures in Epilepsy

      Focal seizures in epilepsy can be localised based on the specific location of the brain where they occur. Temporal lobe seizures are common and may occur with or without impairment of consciousness or awareness. Most patients experience an aura, which is typically a rising epigastric sensation, along with psychic or experiential phenomena such as déjà vu or jamais vu. Less commonly, hallucinations may occur, such as auditory, gustatory, or olfactory hallucinations. These seizures typically last around one minute and are often accompanied by automatisms, such as lip smacking, grabbing, or plucking.

      On the other hand, frontal lobe seizures are characterised by motor symptoms such as head or leg movements, posturing, postictal weakness, and Jacksonian march. Parietal lobe seizures, on the other hand, are sensory in nature and may cause paraesthesia. Finally, occipital lobe seizures may cause visual symptoms such as floaters or flashes. By identifying the specific location and type of seizure, doctors can better diagnose and treat epilepsy in patients.

    • This question is part of the following fields:

      • Neurological System
      39.3
      Seconds
  • Question 4 - You are evaluating a different patient's visual acuity (VA) using a Snellen chart....

    Correct

    • You are evaluating a different patient's visual acuity (VA) using a Snellen chart. This patient's uncorrected visual acuity (UCVA) is superior to 'normal vision' in the right eye (OD) and only half as good as 'normal vision' in the left eye (OS).

      Please provide the appropriate visual acuity format for this patient using the following format:

      OD x/y a/b OS

      Your Answer: OD 6/4 6/12 OS

      Explanation:

      Evaluating visual acuity is a crucial aspect of an eye exam, with a VA of 6/4 indicating superior vision compared to the norm. To determine the best corrected visual acuity, a pinhole test can be utilized.

      Typically, a VA of 6/6 is considered standard vision. The numerator denotes the distance (in meters) between the individual and the test chart in optimal lighting conditions. The denominator signifies the distance required for someone with 6/6 vision to view the same line.

      By minimizing optic aberrations and temporarily eliminating refractive errors, the pinhole test can provide the most optimal visual acuity achievable with glasses when viewed in good lighting.

      A gradual decline in vision is a prevalent issue among the elderly population, leading them to seek guidance from healthcare providers. This condition can be attributed to various causes, including cataracts and age-related macular degeneration. Both of these conditions can cause a gradual loss of vision over time, making it difficult for individuals to perform daily activities such as reading, driving, and recognizing faces. As a result, it is essential for individuals experiencing a decline in vision to seek medical attention promptly to receive appropriate treatment and prevent further deterioration.

    • This question is part of the following fields:

      • Neurological System
      9.8
      Seconds
  • Question 5 - A 72-year-old man presents with biliary colic and an abdominal aortic aneurysm measuring...

    Incorrect

    • A 72-year-old man presents with biliary colic and an abdominal aortic aneurysm measuring 4.8 cm is discovered. Which of the following statements regarding this condition is false?

      Your Answer: Aortoduodenal fistula is a recognised complication following repair.

      Correct Answer: The wall will be composed of dense fibrous tissue only

      Explanation:

      These aneurysms are genuine and consist of all three layers of the arterial wall.

      Understanding Abdominal Aortic Aneurysms

      Abdominal aortic aneurysms occur when the elastic proteins in the extracellular matrix fail, causing the arterial wall to dilate. This is typically caused by degenerative disease and can be identified by a diameter of 3 cm or greater. The development of aneurysms is complex and involves the loss of the intima and elastic fibers from the media, which is associated with increased proteolytic activity and lymphocytic infiltration.

      Smoking and hypertension are major risk factors for the development of aneurysms, while rare causes include syphilis and connective tissue diseases such as Ehlers Danlos type 1 and Marfan’s syndrome. It is important to understand the underlying causes and risk factors for abdominal aortic aneurysms in order to prevent and treat this potentially life-threatening condition.

    • This question is part of the following fields:

      • Cardiovascular System
      47.3
      Seconds
  • Question 6 - A 22-year-old man was admitted earlier in the day with a fractured fibula...

    Correct

    • A 22-year-old man was admitted earlier in the day with a fractured fibula following a skateboarding accident. He underwent surgical repair but has suddenly developed a tachycardia on the recovery ward. His vital signs reveal a heart rate of 170 beats/minute, respiratory rate of 20 breaths/minute, and blood pressure of 80/55 mmHg. His ECG shows ventricular tachycardia. The physician decides to perform synchronised DC cardioversion.

      What is the most appropriate course of action for this patient?

      Your Answer: DC cardioversion shock synchronised to the ECG R wave

      Explanation:

      When a patient displays adverse features such as shock, syncope, heart failure, or myocardial ischaemia while in ventricular tachycardia, electrical cardioversion synchronized to the R wave is the recommended treatment. If the patient does not respond to up to three synchronized DC shocks, it is important to seek expert help and administer 300mg of IV adenosine. Administering IV fluids would not be an appropriate management choice as it would not affect the patient’s cardiac rhythm.

      Cardioversion for Atrial Fibrillation

      Cardioversion may be used in two scenarios for atrial fibrillation (AF): as an emergency if the patient is haemodynamically unstable, or as an elective procedure where a rhythm control strategy is preferred. Electrical cardioversion is synchronised to the R wave to prevent delivery of a shock during the vulnerable period of cardiac repolarisation when ventricular fibrillation can be induced.

      In the elective scenario for rhythm control, the 2014 NICE guidelines recommend offering rate or rhythm control if the onset of the arrhythmia is less than 48 hours, and starting rate control if it is more than 48 hours or is uncertain.

      If the AF is definitely of less than 48 hours onset, patients should be heparinised. Patients who have risk factors for ischaemic stroke should be put on lifelong oral anticoagulation. Otherwise, patients may be cardioverted using either electrical or pharmacological methods.

      If the patient has been in AF for more than 48 hours, anticoagulation should be given for at least 3 weeks prior to cardioversion. An alternative strategy is to perform a transoesophageal echo (TOE) to exclude a left atrial appendage (LAA) thrombus. If excluded, patients may be heparinised and cardioverted immediately. NICE recommends electrical cardioversion in this scenario, rather than pharmacological.

      If there is a high risk of cardioversion failure, it is recommended to have at least 4 weeks of amiodarone or sotalol prior to electrical cardioversion. Following electrical cardioversion, patients should be anticoagulated for at least 4 weeks. After this time, decisions about anticoagulation should be taken on an individual basis depending on the risk of recurrence.

    • This question is part of the following fields:

      • Cardiovascular System
      53.6
      Seconds
  • Question 7 - A 22-year-old man presents to the emergency department with complaints of weakness in...

    Incorrect

    • A 22-year-old man presents to the emergency department with complaints of weakness in his right wrist. He reports heavy drinking the previous night and falling asleep with his arm hanging over a chair's armrest. Upon examination, there is weakness in the extensor muscles of the forearm, and a radial nerve palsy is diagnosed. A neurologist later uses an electromyogram, which indicates the presence of axonotmesis in the radial nerve.

      What is a reasonable expectation for the patient's recovery?

      Your Answer: Full recovery of function in 4 days

      Correct Answer: Full recovery of function in 12 months

      Explanation:

      When a nerve is crushed, it can lead to axonotmesis, which is a serious injury. However, in most cases, patients can fully recover from this type of injury, but the process is slow.

      The radial nerve of the patient in this case was compressed for a long time due to falling asleep on an armrest, resulting in axonotmesis. Although complete recovery is probable, it can take up to a year for the axons to regenerate.

      Nerve injuries can be classified into three types: neuropraxia, axonotmesis, and neurotmesis. Neuropraxia occurs when the nerve is intact but its electrical conduction is affected. However, full recovery is possible, and autonomic function is preserved. Wallerian degeneration, which is the degeneration of axons distal to the site of injury, does not occur. Axonotmesis, on the other hand, happens when the axon is damaged, but the myelin sheath is preserved, and the connective tissue framework is not affected. Wallerian degeneration occurs in this type of injury. Lastly, neurotmesis is the most severe type of nerve injury, where there is a disruption of the axon, myelin sheath, and surrounding connective tissue. Wallerian degeneration also occurs in this type of injury.

      Wallerian degeneration typically begins 24-36 hours following the injury. Axons are excitable before degeneration occurs, and the myelin sheath degenerates and is phagocytosed by tissue macrophages. Neuronal repair may only occur physiologically where nerves are in direct contact. However, nerve regeneration may be hampered when a large defect is present, and it may not occur at all or result in the formation of a neuroma. If nerve regrowth occurs, it typically happens at a rate of 1mm per day.

    • This question is part of the following fields:

      • Neurological System
      50.3
      Seconds
  • Question 8 - A 32-year-old male is referred to the endocrine clinic due to a change...

    Correct

    • A 32-year-old male is referred to the endocrine clinic due to a change in his shoe size and numbness in his hand. He reports increased sweating and oily skin. The endocrinologist suspects pituitary gland pathology and orders an MRI. What is the most abundant secretory cell type in the anterior pituitary gland?

      Your Answer: Somatotrophs

      Explanation:

      Understanding Growth Hormone and Its Functions

      Growth hormone (GH) is a hormone produced by the somatotroph cells in the anterior pituitary gland. It plays a crucial role in postnatal growth and development, as well as in regulating protein, lipid, and carbohydrate metabolism. GH acts on a transmembrane receptor for growth factor, leading to receptor dimerization and direct or indirect effects on tissues via insulin-like growth factor 1 (IGF-1), which is primarily secreted by the liver.

      GH secretion is regulated by various factors, including growth hormone releasing hormone (GHRH), fasting, exercise, and sleep. Conversely, glucose and somatostatin can decrease GH secretion. Disorders associated with GH include acromegaly, which results from excess GH, and GH deficiency, which can lead to short stature.

      In summary, GH is a vital hormone that plays a significant role in growth and metabolism. Understanding its functions and regulation can help in the diagnosis and treatment of GH-related disorders.

    • This question is part of the following fields:

      • Endocrine System
      21.3
      Seconds
  • Question 9 - Can you provide a definition for pseudostratified epithelium? ...

    Correct

    • Can you provide a definition for pseudostratified epithelium?

      Your Answer: A single layer of epithelial cells with nuclei at different height

      Explanation:

      Types of Epithelial Tissue

      Epithelial tissue is a type of tissue that lines the surfaces of organs, glands, and body cavities. There are different types of epithelial tissue, including simple, stratified, and transitional epithelium. Pseudostratified epithelium is a type of simple epithelium that appears to be several cells deep due to the nuclei being at different heights. This gives the illusion of a stratified epithelium. The lining of the conducting airways, up to the respiratory bronchioles, is lined by ciliated, pseudostratified columnar epithelium.

      A simple epithelium is a single layer of epithelial cells with nuclei at the same height, while a stratified epithelium is multiple layers of epithelial cells upon each other, usually stratified squamous. The skin is an example of a stratified epithelium. A transitional epithelium is multiple layers of epithelial cells that stretch over each other. This type of epithelium is found in the ureters and bladder. When contracted, the epithelium is stratified, but when stretched, the epithelial cells slide to give a simple epithelium. This allows for expansion with a minimal increase in wall pressure.

    • This question is part of the following fields:

      • Clinical Sciences
      11.7
      Seconds
  • Question 10 - A 6-year-old boy presents to the clinic after experiencing his seventh fracture. Upon...

    Correct

    • A 6-year-old boy presents to the clinic after experiencing his seventh fracture. Upon examination, his x-rays reveal dense bones with multiple cortical layers. He also has a mild normocytic anemia and low platelets, but his sclera appear white. What is the probable diagnosis?

      Your Answer: Osteopetrosis

      Explanation:

      Osteopetrosis and its Distinction from Other Bone Disorders

      Osteopetrosis is a congenital condition that affects bone reabsorption, leading to the appearance of a ‘bone within a bone’ from multiple cortical layers. Despite the increased density, bones become brittle and prone to fracture, and there is no room for the marrow to grow, causing bone marrow failure and peripheral cytopenias. Additionally, bones expand and frequently cause neural compression symptoms.

      When diagnosing osteopetrosis, it is important to exclude non-accidental injury (NAI) due to the repeated bone injury, but NAI alone cannot account for the x-ray findings or the blood counts. However, a diagnosis of osteopetrosis does not rule out the possibility of NAI co-existing with the condition.

      Other bone disorders, such as acute lymphocytic leukemia and aplastic anemia, may present with peripheral cytopenias but not the x-ray appearances or multiple fractures. On the other hand, osteogenesis imperfecta (OI) is a congenital condition of brittle bones susceptible to multiple fractures due to a mutation in type I collagen. The most common form, type I OI, is inherited as an autosomal dominant condition and is associated with blue sclerae and neural deafness from bone overgrowth. X-rays show reduced bone density with cortical disorganization.

      In summary, the distinct features of osteopetrosis and its differentiation from other bone disorders is crucial in making an accurate diagnosis and providing appropriate treatment.

    • This question is part of the following fields:

      • Rheumatology
      66.3
      Seconds
  • Question 11 - Sarah is a 60-year-old female who has been recently diagnosed with hypertension. After...

    Incorrect

    • Sarah is a 60-year-old female who has been recently diagnosed with hypertension. After a 3-month trial of improving diet and increasing exercise, her blood pressure is still elevated at 160/100 mmHg. Her doctor decides to start her on enalapril, an ACE inhibitor, to treat her hypertension.

      At what location in the body is enalapril activated to its pharmacologically active compound?

      Your Answer: Lung tissue

      Correct Answer: Under phase 1 metabolism in the liver

      Explanation:

      ACE inhibitors are prodrugs that require activation through phase 1 metabolism in the liver, except for captopril and lisinopril which are administered as active drugs. The hepatic esterolysis process converts ACE inhibitors into their active metabolite, allowing them to function as subtype 1B prodrugs. It is important to note that ACE inhibitors are not activated at the site of therapeutic action, and belong to subtype 1A and 2C prodrugs that are activated intracellularly or extracellularly at the therapeutic site, respectively. Answer 3 is a distractor, as ACE inhibitors do not activate ACE in the lung, but rather inhibit its activity. Answer 5 is also incorrect, as most ACE inhibitors require activation through metabolism.

      Angiotensin-converting enzyme (ACE) inhibitors are commonly used as the first-line treatment for hypertension and heart failure in younger patients. However, they may not be as effective in treating hypertensive Afro-Caribbean patients. ACE inhibitors are also used to treat diabetic nephropathy and prevent ischaemic heart disease. These drugs work by inhibiting the conversion of angiotensin I to angiotensin II and are metabolized in the liver.

      While ACE inhibitors are generally well-tolerated, they can cause side effects such as cough, angioedema, hyperkalaemia, and first-dose hypotension. Patients with certain conditions, such as renovascular disease, aortic stenosis, or hereditary or idiopathic angioedema, should use ACE inhibitors with caution or avoid them altogether. Pregnant and breastfeeding women should also avoid these drugs.

      Patients taking high-dose diuretics may be at increased risk of hypotension when using ACE inhibitors. Therefore, it is important to monitor urea and electrolyte levels before and after starting treatment, as well as any changes in creatinine and potassium levels. Acceptable changes include a 30% increase in serum creatinine from baseline and an increase in potassium up to 5.5 mmol/l. Patients with undiagnosed bilateral renal artery stenosis may experience significant renal impairment when using ACE inhibitors.

      The current NICE guidelines recommend using a flow chart to manage hypertension, with ACE inhibitors as the first-line treatment for patients under 55 years old. However, individual patient factors and comorbidities should be taken into account when deciding on the best treatment plan.

    • This question is part of the following fields:

      • Cardiovascular System
      18.3
      Seconds
  • Question 12 - A 50-year-old man presents with brisk haematemesis and is taken to the endoscopy...

    Correct

    • A 50-year-old man presents with brisk haematemesis and is taken to the endoscopy department for an upper GI endoscopy. The gastroenterologist identifies an ulcer on the posterior duodenal wall and attempts to control the bleeding with various haemostatic techniques. After an unsuccessful attempt, the surgeon is called for assistance. During the laparotomy and anterior duodenotomy, a vessel is found spurting blood into the duodenal lumen. What is the origin of this vessel?

      Your Answer: Common hepatic artery

      Explanation:

      The gastroduodenal artery originates from the common hepatic artery.

      The Gastroduodenal Artery: Supply and Path

      The gastroduodenal artery is responsible for supplying blood to the pylorus, proximal part of the duodenum, and indirectly to the pancreatic head through the anterior and posterior superior pancreaticoduodenal arteries. It commonly arises from the common hepatic artery of the coeliac trunk and terminates by bifurcating into the right gastroepiploic artery and the superior pancreaticoduodenal artery.

      To better understand the relationship of the gastroduodenal artery to the first part of the duodenum, the stomach is reflected superiorly in an image sourced from Wikipedia. This artery plays a crucial role in providing oxygenated blood to the digestive system, ensuring proper functioning and health.

    • This question is part of the following fields:

      • Gastrointestinal System
      40.4
      Seconds
  • Question 13 - A senior citizen who is unfamiliar to you arrives with seizures. A companion...

    Incorrect

    • A senior citizen who is unfamiliar to you arrives with seizures. A companion describes that he had been experiencing a prickling sensation around his mouth and muscle contractions in his extremities.

      What blood test outcomes would you anticipate from these indications?

      Your Answer:

      Correct Answer: Hypocalcaemia

      Explanation:

      The correct answer is hypocalcaemia, which is characterized by perioral paraesthesia, cramps, tetany, and convulsions. Hypophosphatemia and hypokalaemia are not the most appropriate answers, as they would not cause these symptoms. Sepsis is also an incorrect answer.

      Hypocalcaemia: Symptoms and Signs

      Hypocalcaemia is a condition characterized by low levels of calcium in the blood. As calcium is essential for proper muscle and nerve function, many of the symptoms and signs of hypocalcaemia are related to neuromuscular excitability. The most common features of hypocalcaemia include muscle twitching, cramping, and spasms, as well as perioral paraesthesia. In chronic cases, patients may experience depression and cataracts. An electrocardiogram (ECG) may show a prolonged QT interval.

      Two specific signs that are commonly used to diagnose hypocalcaemia are Trousseau’s sign and Chvostek’s sign. Trousseau’s sign is observed when the brachial artery is occluded by inflating the blood pressure cuff and maintaining pressure above systolic. This causes wrist flexion and fingers to be drawn together, which is seen in around 95% of patients with hypocalcaemia and around 1% of normocalcaemic people. Chvostek’s sign is observed when tapping over the parotid gland causes facial muscles to twitch. This sign is seen in around 70% of patients with hypocalcaemia and around 10% of normocalcaemic people. Overall, hypocalcaemia can cause a range of symptoms and signs that are related to neuromuscular excitability, and specific diagnostic signs can be used to confirm the diagnosis.

    • This question is part of the following fields:

      • Renal System
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  • Question 14 - A 58-year-old man presents to the emergency department with fast atrial fibrillation. Despite...

    Incorrect

    • A 58-year-old man presents to the emergency department with fast atrial fibrillation. Despite beta-blocker therapy, he requires cardioversion and is subsequently prescribed flecainide by the cardiologist. What is the mechanism of action of flecainide?

      Your Answer:

      Correct Answer: Blocking the Nav1.5 sodium channels in the heart

      Explanation:

      Flecainide, Procainamide, and Ibutilide all affect the heart’s electrical activity by blocking or prolonging certain ion channels. Flecainide and Procainamide block sodium channels, while Ibutilide blocks potassium channels. Bisoprolol works by blocking beta one adrenergic receptors, which reduces stimulation of the heart muscle. Dronedarone’s mechanism of action is not fully understood, but it is believed to affect both potassium and calcium channels.

      Flecainide: A Sodium Channel Blocker for Cardiac Arrhythmias

      Flecainide is a type of antiarrhythmic drug that belongs to the Vaughan Williams class 1c. It works by blocking the Nav1.5 sodium channels, which slows down the conduction of the action potential. This can cause the QRS complex to widen and the PR interval to prolong. Flecainide is commonly used to treat atrial fibrillation and supraventricular tachycardia associated with accessory pathways like Wolff-Parkinson-White syndrome.

      However, it is important to note that flecainide is contraindicated in certain situations. For instance, it should not be used in patients who have recently experienced a myocardial infarction or have structural heart disease like heart failure. It is also not recommended for those with sinus node dysfunction or second-degree or greater AV block, as well as those with atrial flutter.

      Like any medication, flecainide can cause adverse effects. It may have a negative inotropic effect, which means it can weaken the heart’s contractions. It can also cause bradycardia, proarrhythmic effects, oral paraesthesia, and visual disturbances. Therefore, it is important to use flecainide only under the guidance of a healthcare professional and to report any unusual symptoms immediately.

    • This question is part of the following fields:

      • General Principles
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  • Question 15 - A 30-year-old woman is being evaluated for possible Addison's disease due to experiencing...

    Incorrect

    • A 30-year-old woman is being evaluated for possible Addison's disease due to experiencing atypical exhaustion and observing a mild bronzing of her skin. The underlying cause is believed to be an autoimmune assault on the adrenal cortex, leading to reduced secretion of aldosterone.

      What is the typical physiological trigger for the production of this steroid hormone?

      Your Answer:

      Correct Answer: Angiotensin II

      Explanation:

      The correct answer is Angiotensin II, which stimulates the release of aldosterone. It also has the ability to stimulate the release of ADH, increase blood pressure, and influence the kidneys to retain sodium and water.

      Angiotensin I is not the correct answer as it is converted to angiotensin II by ACE and does not have a direct role in the release of aldosterone by the adrenal cortex.

      ACE is released by the capillaries in the lungs and is responsible for converting angiotensin I to angiotensin II.

      Angiotensinogen is not the correct answer as it is the first step in the renin-angiotensin-aldosterone system. It is released by the liver and converted to angiotensin I by renin.

      The renin-angiotensin-aldosterone system is a complex system that regulates blood pressure and fluid balance in the body. The adrenal cortex is divided into three zones, each producing different hormones. The zona glomerulosa produces mineralocorticoids, mainly aldosterone, which helps regulate sodium and potassium levels in the body. Renin is an enzyme released by the renal juxtaglomerular cells in response to reduced renal perfusion, hyponatremia, and sympathetic nerve stimulation. It hydrolyses angiotensinogen to form angiotensin I, which is then converted to angiotensin II by angiotensin-converting enzyme in the lungs. Angiotensin II has various actions, including causing vasoconstriction, stimulating thirst, and increasing proximal tubule Na+/H+ activity. It also stimulates aldosterone and ADH release, which causes retention of Na+ in exchange for K+/H+ in the distal tubule.

    • This question is part of the following fields:

      • Renal System
      0
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  • Question 16 - A 25-year-old man is in a physical altercation and sustains a stab wound...

    Incorrect

    • A 25-year-old man is in a physical altercation and sustains a stab wound to his upper arm, resulting in transection of the ulnar nerve. Which muscle among the following options will remain unaffected by this injury?

      Your Answer:

      Correct Answer: Pronator teres

      Explanation:

      The ulnar nerve innervates several intrinsic muscles of the hand, including the medial lumbricals, adductor pollicis, flexor digitorum profundus/flexor digiti minimi, interossei, abductor digiti minimi, and opponens. However, it does not supply the thenar muscles and the first two lumbricals, which are instead innervated by the median nerve.

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

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

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

    • This question is part of the following fields:

      • Neurological System
      0
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  • Question 17 - A 14-year-old girl presents to her GP with complaints of earache and hearing...

    Incorrect

    • A 14-year-old girl presents to her GP with complaints of earache and hearing difficulty in her left ear. Upon examination, her GP observes a bulging tympanic membrane and diagnoses her with acute otitis media. The GP prescribes a course of oral antibiotics.

      However, after a few days, the girl's fever persists and her pain worsens, prompting her to visit the emergency department. Upon examination, the girl has a tender and erythematous retro-auricular swelling with a temperature of 38.9ºC. She has no ear discharge, and the rest of her examination is unremarkable.

      What complication has developed in this case?

      Your Answer:

      Correct Answer: Mastoiditis

      Explanation:

      Mastoiditis is a potential complication of acute otitis media, which can cause pain and swelling behind the ear over the mastoid bone. However, there is no evidence of tympanic membrane perforation, neurological symptoms or signs of meningitis or brain abscess, or facial nerve injury in this case.

      Acute otitis media is a common condition in young children, often caused by bacterial infections following viral upper respiratory tract infections. Symptoms include ear pain, fever, and hearing loss, and diagnosis is based on criteria such as the presence of a middle ear effusion and inflammation of the tympanic membrane. Antibiotics may be prescribed in certain cases, and complications can include perforation of the tympanic membrane, hearing loss, and more serious conditions such as meningitis and brain abscess.

    • This question is part of the following fields:

      • Respiratory System
      0
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  • Question 18 - A 32-year-old man comes to you complaining of persistent diarrhoea for the past...

    Incorrect

    • A 32-year-old man comes to you complaining of persistent diarrhoea for the past 10 days. He describes his diarrhoea as watery and foul-smelling, but denies any blood. He feels exhausted and asks for a prescription for an antidiarrhoeal medication. He has no notable medical history.

      The stool cultures come back negative, and you contemplate starting the patient on diphenoxylate. Can you explain the mechanism of action of this drug?

      Your Answer:

      Correct Answer: Inhibits peristalsis by acting on μ-opioid in the GI tract

      Explanation:

      Diphenoxylate slows down peristalsis in the GI tract by acting on μ-opioid receptors.

      Increased gut motility can be achieved through the positive cholinergic effect of muscarinic receptor activation.

      All other options are inaccurate.

      Antidiarrhoeal Agents: Opioid Agonists

      Antidiarrhoeal agents are medications used to treat diarrhoea. Opioid agonists are a type of antidiarrhoeal agent that work by slowing down the movement of the intestines, which reduces the frequency and urgency of bowel movements. Two common opioid agonists used for this purpose are loperamide and diphenoxylate.

      Loperamide is available over-the-counter and is often used to treat acute diarrhoea. It works by binding to opioid receptors in the intestines, which reduces the contractions of the muscles in the intestinal wall. This slows down the movement of food and waste through the intestines, allowing more time for water to be absorbed and resulting in firmer stools.

      Diphenoxylate is a prescription medication that is often used to treat chronic diarrhoea. It works in a similar way to loperamide, but is often combined with atropine to discourage abuse and overdose.

      Overall, opioid agonists are effective at treating diarrhoea, but should be used with caution and under the guidance of a healthcare professional. They can cause side effects such as constipation, dizziness, and nausea, and may interact with other medications.

    • This question is part of the following fields:

      • Gastrointestinal System
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  • Question 19 - A carpal tunnel release results in median nerve damage. Which muscles will be...

    Incorrect

    • A carpal tunnel release results in median nerve damage. Which muscles will be impacted by this in the patient?

      Your Answer:

      Correct Answer: Abductor pollicis brevis

      Explanation:

      Only the abductor pollicis brevis is innervated by the median nerve, while the other muscles are innervated by different nerves. It is important to be careful not to confuse the terms adductor and abductor when discussing muscle innervation.

      Abductor Pollicis Brevis: Anatomy and Function

      The abductor pollicis brevis is a muscle located in the palm of the hand. It originates from the flexor retinaculum, scaphoid, and trapezium bones and inserts into the radial side of the proximal phalanx of the thumb via a short tendon. The muscle is innervated by the recurrent branch of the median nerve in the palm.

      The main function of the abductor pollicis brevis is to abduct the thumb at the carpometacarpal and metacarpophalangeal joints. This causes the thumb to move anteriorly at right angles to the plane of the palm and to rotate medially, which is useful for activities such as typing. When the thumb is fully abducted, there is an angulation of around 30 degrees between the proximal phalanx and the metacarpal.

      Abduction of the thumb involves medial rotation of the metacarpal, and the abductor pollicis brevis is used along with the opponens pollicis in the initial stages of thumb opposition. Overall, the abductor pollicis brevis plays an important role in the movement and function of the thumb.

    • This question is part of the following fields:

      • Musculoskeletal System And Skin
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  • Question 20 - A passionate surgical resident attempts his first independent splenectomy. The procedure proves to...

    Incorrect

    • A passionate surgical resident attempts his first independent splenectomy. The procedure proves to be more challenging than expected and the resident places a tube drain in the splenic bed at the conclusion of the surgery. Within the next 24 hours, around 500ml of clear fluid drains into the tube. What is the most probable result of biochemical testing on the fluid?

      Elevated creatinine
      28%
      Elevated triglycerides
      10%
      Elevated glucagon
      9%
      Elevated amylase
      25%
      None of the above
      29%

      During a splenectomy, the tail of the pancreas may be harmed, causing the pancreatic duct to drain into the splenic bed, resulting in an increase in amylase levels. Glucagon is not produced in the pancreatic duct.

      Your Answer:

      Correct Answer: Elevated amylase

      Explanation:

      If the tail of the pancreas is damaged during splenectomy, the pancreatic duct may end up draining into the splenic bed. This can result in an increase in amylase levels, but there will be no secretion of glucagon into the pancreatic duct.

      Understanding the Anatomy of the Spleen

      The spleen is a vital organ in the human body, serving as the largest lymphoid organ. It is located below the 9th-12th ribs and has a clenched fist shape. The spleen is an intraperitoneal organ, and its peritoneal attachments condense at the hilum, where the vessels enter the spleen. The blood supply of the spleen is from the splenic artery, which is derived from the coeliac axis, and the splenic vein, which is joined by the IMV and unites with the SMV.

      The spleen is derived from mesenchymal tissue during embryology. It weighs between 75-150g and has several relations with other organs. The diaphragm is superior to the spleen, while the gastric impression is anterior, the kidney is posterior, and the colon is inferior. The hilum of the spleen is formed by the tail of the pancreas and splenic vessels. The spleen also forms the apex of the lesser sac, which contains short gastric vessels.

      In conclusion, understanding the anatomy of the spleen is crucial in comprehending its functions and the role it plays in the human body. The spleen’s location, weight, and relations with other organs are essential in diagnosing and treating spleen-related conditions.

    • This question is part of the following fields:

      • Gastrointestinal System
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  • Question 21 - A 19-year-old rock climber suffers a fall onto his left arm resulting in...

    Incorrect

    • A 19-year-old rock climber suffers a fall onto his left arm resulting in a significant haematoma in the left upper arm. Regrettably, the wound is left unattended and becomes infected. Which of the following alterations is the least probable to happen?

      Your Answer:

      Correct Answer: Leucopenia

      Explanation:

      If leucopenia is present, it would be atypical and necessitate an investigation for an alternative underlying factor.

      Acute inflammation is a response to cell injury in vascularized tissue. It is triggered by chemical factors produced in response to a stimulus, such as fibrin, antibodies, bradykinin, and the complement system. The goal of acute inflammation is to neutralize the offending agent and initiate the repair process. The main characteristics of inflammation are fluid exudation, exudation of plasma proteins, and migration of white blood cells.

      The vascular changes that occur during acute inflammation include transient vasoconstriction, vasodilation, increased permeability of vessels, RBC concentration, and neutrophil margination. These changes are followed by leukocyte extravasation, margination, rolling, and adhesion of neutrophils, transmigration across the endothelium, and migration towards chemotactic stimulus.

      Leukocyte activation is induced by microbes, products of necrotic cells, antigen-antibody complexes, production of prostaglandins, degranulation and secretion of lysosomal enzymes, cytokine secretion, and modulation of leukocyte adhesion molecules. This leads to phagocytosis and termination of the acute inflammatory response.

    • This question is part of the following fields:

      • General Principles
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  • Question 22 - A 63-year-old man arrives at the ER with a recent onset of left-sided...

    Incorrect

    • A 63-year-old man arrives at the ER with a recent onset of left-sided facial paralysis. He reports experiencing a painful rash around his ear on the affected side for the past five days. Your suspicion is Ramsay Hunt syndrome. What virus is responsible for this condition?

      Your Answer:

      Correct Answer: Varicella zoster virus

      Explanation:

      The geniculate ganglion of the facial nerve (CN VII) reactivates the varicella-zoster virus, causing Ramsay Hunt syndrome.

      Infectious mononucleosis (glandular fever) is primarily linked to the Epstein-Barr virus.

      Viral warts are commonly caused by human papillomavirus (HPV), with certain types being associated with gynaecological malignancy. Vaccines are now available to protect against the carcinogenic strains of HPV.

      Oral or genital herpes infections are caused by the herpes simplex virus.

      Understanding Ramsay Hunt Syndrome

      Ramsay Hunt syndrome, also known as herpes zoster oticus, is a condition that occurs when the varicella zoster virus reactivates in the geniculate ganglion of the seventh cranial nerve. The first symptom of this syndrome is often auricular pain, followed by facial nerve palsy and a vesicular rash around the ear. Other symptoms may include vertigo and tinnitus.

      To manage Ramsay Hunt syndrome, doctors typically prescribe oral acyclovir and corticosteroids. These medications can help reduce the severity of symptoms and prevent complications.

    • This question is part of the following fields:

      • Respiratory System
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  • Question 23 - Which of these openings allows the facial nerve to enter the temporal bone?...

    Incorrect

    • Which of these openings allows the facial nerve to enter the temporal bone?

      Your Answer:

      Correct Answer: Internal acoustic meatus

      Explanation:

      The facial nerve passes through the internal acoustic meatus of the temporal bone and emerges from the stylomastoid foramen.

      The facial nerve is responsible for supplying the muscles of facial expression, the digastric muscle, and various glandular structures. It also contains a few afferent fibers that originate in the genicular ganglion and are involved in taste. Bilateral facial nerve palsy can be caused by conditions such as sarcoidosis, Guillain-Barre syndrome, Lyme disease, and bilateral acoustic neuromas. Unilateral facial nerve palsy can be caused by these conditions as well as lower motor neuron issues like Bell’s palsy and upper motor neuron issues like stroke.

      The upper motor neuron lesion typically spares the upper face, specifically the forehead, while a lower motor neuron lesion affects all facial muscles. The facial nerve’s path includes the subarachnoid path, where it originates in the pons and passes through the petrous temporal bone into the internal auditory meatus with the vestibulocochlear nerve. The facial canal path passes superior to the vestibule of the inner ear and contains the geniculate ganglion at the medial aspect of the middle ear. The stylomastoid foramen is where the nerve passes through the tympanic cavity anteriorly and the mastoid antrum posteriorly, and it also includes the posterior auricular nerve and branch to the posterior belly of the digastric and stylohyoid muscle.

    • This question is part of the following fields:

      • Neurological System
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  • Question 24 - As a medical student assisting a consultant cardiologist during a percutaneous coronary angiogram...

    Incorrect

    • As a medical student assisting a consultant cardiologist during a percutaneous coronary angiogram on a male patient, you are shown the patient's previous angiogram that reveals a severe occlusion in the left main stem coronary artery. The consultant then poses a question to you about atherosclerosis. Specifically, which modifiable risk factor is involved in the initial development of the atherosclerotic plaque due to its contribution to shear stress?

      Your Answer:

      Correct Answer: Hypertension

      Explanation:

      The Role of Endothelial Damage in Atherosclerosis

      The development of atherosclerosis requires endothelial damage to occur. Hypertension is the most likely risk factor to cause this damage, as it alters blood flow and increases shearing forces on the endothelium. Once damage occurs, pro-inflammatory mediators are released, leading to leucocyte adhesion and increased permeability in the vessel wall. Endothelial damage is particularly atherogenic due to the release of platelet-derived growth factor and thrombin, which stimulate platelet adhesion and activate the clotting cascade.

      Diabetes mellitus, hypercholesterolaemia, and obesity increase LDL levels, which infiltrate the arterial intima and contribute to the formation of atheromatous plaques. However, before LDLs can infiltrate the vessel wall, they must bind to endothelial adhesion molecules, which are released after endothelial damage occurs. Therefore, hypertension-induced endothelial damage is required for the initial development of atherosclerosis.

      Smoking is also a risk factor for atherosclerosis, but the mechanism is not well understood. It is believed that free radicals and aromatic compounds in tobacco smoke inhibit the production of nitric oxide, leading to endothelial damage. Overall, the role of endothelial damage in atherosclerosis can help identify effective prevention and treatment strategies.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 25 - A 58-year-old patient is having a planned hysterectomy. While the surgery is ongoing,...

    Incorrect

    • A 58-year-old patient is having a planned hysterectomy. While the surgery is ongoing, her blood pressure suddenly decreases to 60/40 mmHg and her heart rate increases to 102 bpm. The anaesthetist decides to give phenylephrine. After a few minutes, the patient's blood pressure returns to 100/80 mmHg and her heart rate drops to 85 bpm.

      What is the mechanism of action of phenylephrine in this scenario?

      Your Answer:

      Correct Answer: α₁ agonist

      Explanation:

      Smooth muscle contraction in blood vessels is mediated by α1 adrenergic receptors, which can be activated by α1 agonists such as phenylephrine. This causes an increase in peripheral vascular resistance and blood pressure. β₁ agonists affect the heart rate and contractility, β₂ agonists affect the airways in the lungs, and M₂ antagonists affect heart rate by blocking the vagus nerve.

      Adrenergic receptors are a type of G protein-coupled receptors that respond to the catecholamines epinephrine and norepinephrine. These receptors are primarily involved in the sympathetic nervous system. There are four types of adrenergic receptors: α1, α2, β1, and β2. Each receptor has a different potency order and primary action. The α1 receptor responds equally to norepinephrine and epinephrine, causing smooth muscle contraction. The α2 receptor has mixed effects and responds equally to both catecholamines. The β1 receptor responds equally to epinephrine and norepinephrine, causing cardiac muscle contraction. The β2 receptor responds much more strongly to epinephrine than norepinephrine, causing smooth muscle relaxation.

    • This question is part of the following fields:

      • General Principles
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  • Question 26 - A 6 month-old infant brought to the clinic for a routine check-up. The...

    Incorrect

    • A 6 month-old infant brought to the clinic for a routine check-up. The child was born via a normal vaginal delivery at 40 weeks of gestation.

      During the examination, the infant was found to be jaundiced.

      Further investigations revealed abnormal liver function tests and a diagnosis of classic galactosaemia was confirmed through a heel prick test.

      What is the underlying reason for the infant's condition?

      Your Answer:

      Correct Answer: Galactose-1-phosphate uridyltransferase (GALT) deficiency

      Explanation:

      The condition known as classic galactosaemia is the result of a deficiency in the enzyme galactose-1-phosphate uridyltransferase (GALT). Other enzyme deficiency conditions include pyruvate kinase deficiency, galactokinase deficiency (also known as galactosemia type 2), and neonatal diabetes mellitus caused by a deficiency in glucokinase.

      Disorders of Galactose Metabolism

      Galactose metabolism is a complex process that involves the breakdown of galactose, a type of sugar found in milk and dairy products. There are two main disorders associated with galactose metabolism: classic galactosemia and galactokinase deficiency. Both of these disorders are inherited in an autosomal recessive manner.

      Classic galactosemia is caused by a deficiency in the enzyme galactose-1-phosphate uridyltransferase, which leads to the accumulation of galactose-1-phosphate. This disorder is characterized by symptoms such as failure to thrive, infantile cataracts, and hepatomegaly.

      On the other hand, galactokinase deficiency is caused by a deficiency in the enzyme galactokinase, which results in the accumulation of galactitol. This disorder is characterized by infantile cataracts, as galactitol accumulates in the lens. Unlike classic galactosemia, there is no hepatic involvement in galactokinase deficiency.

      In summary, disorders of galactose metabolism can have serious consequences and require careful management. Early diagnosis and treatment are essential for improving outcomes and preventing complications.

    • This question is part of the following fields:

      • General Principles
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  • Question 27 - A 30-year-old man presents to you with complaints of numbness and pain in...

    Incorrect

    • A 30-year-old man presents to you with complaints of numbness and pain in his hands and feet since this morning. He had visited for gastroenteritis 3 weeks ago. On examination, he has a bilateral reduction in power of 3/5 in his upper and lower limbs. His speech is normal, and he has no other medical conditions. What is the most probable diagnosis?

      Your Answer:

      Correct Answer: Guillain-Barre syndrome

      Explanation:

      Guillain-Barre syndrome is a condition where the immune system attacks the peripheral nervous system, leading to demyelination. It is often triggered by an infection and presents with rapidly advancing ascending motor neuropathy. Proximal muscles are more affected than distal muscles.

      A stroke or transient ischaemic attack usually has a sudden onset and causes unilateral symptoms such as facial droop, arm weakness, and slurred speech.

      Raynaud’s disease causes numbness and pain in the fingers and toes, typically in response to cold weather or stress.

      Guillain-Barre Syndrome: A Breakdown of its Features

      Guillain-Barre syndrome is a condition that occurs when the immune system attacks the peripheral nervous system, resulting in demyelination. This is often triggered by an infection, with Campylobacter jejuni being a common culprit. In the initial stages of the illness, around 65% of patients experience back or leg pain. However, the characteristic feature of Guillain-Barre syndrome is progressive, symmetrical weakness of all limbs, with the legs being affected first in an ascending pattern. Reflexes are reduced or absent, and sensory symptoms tend to be mild. Other features may include a history of gastroenteritis, respiratory muscle weakness, cranial nerve involvement, diplopia, bilateral facial nerve palsy, oropharyngeal weakness, and autonomic involvement, which can lead to urinary retention and diarrhea. Less common findings may include papilloedema, which is thought to be secondary to reduced CSF resorption. To diagnose Guillain-Barre syndrome, a lumbar puncture may be performed, which can reveal a rise in protein with a normal white blood cell count (albuminocytologic dissociation) in 66% of cases. Nerve conduction studies may also be conducted, which can show decreased motor nerve conduction velocity due to demyelination, prolonged distal motor latency, and increased F wave latency.

    • This question is part of the following fields:

      • Neurological System
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  • Question 28 - A 70-year-old man visits the endocrinology clinic complaining of muscle cramps, headaches, and...

    Incorrect

    • A 70-year-old man visits the endocrinology clinic complaining of muscle cramps, headaches, and lethargy. During the clinic visit, his vital signs are heart rate 80/min, respiratory rate 18/min, blood pressure 150/100 mmHg, temperature 36.5ºC, and saturations 99% on air. Recent blood tests reveal:

      - Na+ 147 mmol/L (135 - 145)
      - K+ 3.2 mmol/L (3.5 - 5.0)
      - Bicarbonate 28 mmol/L (22 - 29)
      - Urea 6.0 mmol/L (2.0 - 7.0)
      - Creatinine 95 µmol/L (55 - 120)

      An adrenal mass is detected on his abdominal CT scan. Can you identify where the hormone responsible for his symptoms is produced?

      Your Answer:

      Correct Answer: Zona glomerulosa

      Explanation:

      The correct answer is the zona glomerulosa. This patient is experiencing symptoms of hyperaldosteronism, which is likely caused by an adenoma in the zona glomerulosa, as indicated by the mass seen on CT scan (also known as Conn’s syndrome). The adenoma stimulates the production of aldosterone, leading to hypertension and hypokalemia.

      The adrenal medulla produces catecholamines, such as adrenaline and noradrenaline.

      The juxtaglomerular apparatus is located in the kidney and produces renin in response to decreased renal perfusion.

      The zona fasciculata is the middle layer of the adrenal cortex and is responsible for producing glucocorticoids, such as cortisol.

      The zona reticularis is the innermost layer of the adrenal cortex and produces androgens, such as dehydroepiandrosterone (DHEA).

      The renin-angiotensin-aldosterone system is a complex system that regulates blood pressure and fluid balance in the body. The adrenal cortex is divided into three zones, each producing different hormones. The zona glomerulosa produces mineralocorticoids, mainly aldosterone, which helps regulate sodium and potassium levels in the body. Renin is an enzyme released by the renal juxtaglomerular cells in response to reduced renal perfusion, hyponatremia, and sympathetic nerve stimulation. It hydrolyses angiotensinogen to form angiotensin I, which is then converted to angiotensin II by angiotensin-converting enzyme in the lungs. Angiotensin II has various actions, including causing vasoconstriction, stimulating thirst, and increasing proximal tubule Na+/H+ activity. It also stimulates aldosterone and ADH release, which causes retention of Na+ in exchange for K+/H+ in the distal tubule.

    • This question is part of the following fields:

      • Renal System
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  • Question 29 - A 50-year-old woman has been diagnosed with breast cancer and her oncologist has...

    Incorrect

    • A 50-year-old woman has been diagnosed with breast cancer and her oncologist has recommended starting her on tamoxifen. What is the mechanism of action of this medication?

      Your Answer:

      Correct Answer: Selective oestrogen receptor modulator

      Explanation:

      Tamoxifen is a medication commonly used in the treatment of oestrogen-receptor positive breast cancer. It works by exhibiting anti-oestrogenic activity in breast tissue, which helps to prevent the progression of breast cancer. However, it also has oestrogenic activity in the uterus, which can increase the risk of endometrial cancers.

      Ulipristal acetate is a selective progesterone receptor modulator that is often used as emergency contraception to prevent pregnancies up to 5 days after unprotected sex.

      Anastrozole is an aromatase inhibitor that is used to treat breast cancer with positive progesterone receptors.

      Trastuzumab is an example of an HER-2 antagonist that is used to treat breast cancer patients with positive HER-2 receptors. HER-2 is a receptor that plays a role in cell growth and differentiation, and overexpression of HER-2 can lead to uncontrolled cell division.

      Doxorubicin is an anthracycline that works by stabilising the topoisomerase II enzyme, which prevents DNA replication by preventing coiling of DNA during transcription.

      Tamoxifen and its Adverse Effects

      Tamoxifen is a medication used in the treatment of breast cancer that is positive for oestrogen receptors. It is classified as a Selective oEstrogen Receptor Modulator (SERM) and works by acting as an antagonist and partial agonist of the oestrogen receptor. However, the use of tamoxifen can lead to several adverse effects. These include menstrual disturbances such as vaginal bleeding and amenorrhoea, as well as hot flushes which can cause 3% of patients to stop taking the medication due to climacteric side-effects. Additionally, tamoxifen increases the risk of venous thromboembolism and endometrial cancer.

      To manage breast cancer, tamoxifen is typically prescribed for a period of 5 years following the removal of the tumour. However, due to the risk of endometrial cancer associated with tamoxifen, an alternative medication called raloxifene may be used. Raloxifene is a pure oestrogen receptor antagonist and carries a lower risk of endometrial cancer. It is important for patients to discuss the potential risks and benefits of tamoxifen and other medications with their healthcare provider before starting treatment.

    • This question is part of the following fields:

      • General Principles
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  • Question 30 - A 65-year-old woman is preparing for surgery to remove her submandibular gland due...

    Incorrect

    • A 65-year-old woman is preparing for surgery to remove her submandibular gland due to recurrent sialadenitis. What is a significant structure that is located medially to the gland?

      Your Answer:

      Correct Answer: Mylohyoid muscle

      Explanation:

      Muscles and Arteries of the Head and Neck

      The mylohyoid muscle is situated close to the superficial part of the submandibular gland. Meanwhile, the genioglossus muscle originates from the mandible and attaches to the tongue and hyoid bone. This muscle is responsible for tongue movement and swallowing. Another muscle in the head and neck region is the lateral pterygoid muscle, which is located in the infratemporal fossa of the skull. It is a two-headed muscle that aids in chewing and movement of the temporomandibular joint. Lastly, the maxillary artery arises posterior to the mandibular neck and passes between the sphenomandibular ligament and ramus of the mandible. This artery supplies blood to the deep structures of the face and maxilla. the anatomy of these muscles and arteries is crucial in diagnosing and treating various head and neck conditions.

    • This question is part of the following fields:

      • Clinical Sciences
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  • Question 31 - A 79-year-old man is admitted to the hospital after experiencing severe dizziness, vertigo,...

    Incorrect

    • A 79-year-old man is admitted to the hospital after experiencing severe dizziness, vertigo, slurred speech, and nausea with vomiting. The diagnosis reveals a basilar artery stroke. Which blood vessels combine to form the affected artery?

      Your Answer:

      Correct Answer: Vertebral arteries

      Explanation:

      The Circle of Willis is an anastomosis formed by the internal carotid arteries and vertebral arteries on the bottom surface of the brain. It is divided into two halves and is made up of various arteries, including the anterior communicating artery, anterior cerebral artery, internal carotid artery, posterior communicating artery, and posterior cerebral arteries. The circle and its branches supply blood to important areas of the brain, such as the corpus striatum, internal capsule, diencephalon, and midbrain.

      The vertebral arteries enter the cranial cavity through the foramen magnum and lie in the subarachnoid space. They then ascend on the anterior surface of the medulla oblongata and unite to form the basilar artery at the base of the pons. The basilar artery has several branches, including the anterior inferior cerebellar artery, labyrinthine artery, pontine arteries, superior cerebellar artery, and posterior cerebral artery.

      The internal carotid arteries also have several branches, such as the posterior communicating artery, anterior cerebral artery, middle cerebral artery, and anterior choroid artery. These arteries supply blood to different parts of the brain, including the frontal, temporal, and parietal lobes. Overall, the Circle of Willis and its branches play a crucial role in providing oxygen and nutrients to the brain.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 32 - Which muscle is innervated by the superficial peroneal nerve? ...

    Incorrect

    • Which muscle is innervated by the superficial peroneal nerve?

      Your Answer:

      Correct Answer: Peroneus brevis

      Explanation:

      Anatomy of the Superficial Peroneal Nerve

      The superficial peroneal nerve is responsible for supplying the lateral compartment of the leg, specifically the peroneus longus and peroneus brevis muscles which aid in eversion and plantar flexion. It also provides sensation over the dorsum of the foot, excluding the first web space which is innervated by the deep peroneal nerve.

      The nerve passes between the peroneus longus and peroneus brevis muscles along the proximal one-third of the fibula. Approximately 10-12 cm above the tip of the lateral malleolus, the nerve pierces the fascia. It then bifurcates into intermediate and medial dorsal cutaneous nerves about 6-7 cm distal to the fibula.

      Understanding the anatomy of the superficial peroneal nerve is important in diagnosing and treating conditions that affect the lateral compartment of the leg and dorsum of the foot. Injuries or compression of the nerve can result in weakness or numbness in the affected areas.

    • This question is part of the following fields:

      • Neurological System
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  • Question 33 - Samantha is a 63-year-old female who has just been diagnosed with hypertension. Her...

    Incorrect

    • Samantha is a 63-year-old female who has just been diagnosed with hypertension. Her physician informs her that her average blood pressure is influenced by various bodily processes, such as heart function, nervous system activity, and blood vessel diameter. Assuming an average cardiac output (CO) of 4L/min, Samantha's mean arterial pressure (MAP) is recorded at 140mmHg during her examination.

      What is Samantha's systemic vascular resistance (SVR) based on these measurements?

      Your Answer:

      Correct Answer: 35 mmhg⋅min⋅mL-1

      Explanation:

      The equation used to calculate systemic vascular resistance is SVR = MAP / CO. For example, if the mean arterial pressure (MAP) is 140 mmHg and the cardiac output (CO) is 4 mL/min, then the SVR would be 35 mmHg⋅min⋅mL-1. Although the theoretical equation for SVR is more complex, it is often simplified by assuming that central venous pressure (CVP) is negligible. However, in reality, MAP is typically measured directly or indirectly using arterial pressure measurements. The equation for calculating MAP at rest is MAP = diastolic pressure + 1/3(pulse pressure), where pulse pressure is calculated as systolic pressure minus diastolic pressure.

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

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

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

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 34 - Which of the following is linked to inadequate wound healing? ...

    Incorrect

    • Which of the following is linked to inadequate wound healing?

      Your Answer:

      Correct Answer: Jaundice

      Explanation:

      A mnemonic to recall the factors that impact wound healing is DID NOT HEAL. This stands for Diabetes, Infection, Irradiation, Drugs (such as steroids and chemotherapy), Nutritional deficiencies (specifically vitamin A, C, and zinc, as well as manganese), Neoplasia, Object (foreign material), Tissue necrosis, Hypoxia, Excess tension on wound, Another wound, and Low temperature or Liver jaundice.

      The Stages of Wound Healing and Common Problems with Scars

      Wound healing is a complex process that involves several stages, including haemostasis, inflammation, regeneration, and remodeling. During haemostasis, the body forms a clot to stop bleeding. Inflammation occurs next, where immune cells migrate to the wound and release growth factors to stimulate the production of new tissue. Regeneration involves the formation of new blood vessels and the production of collagen to rebuild the damaged tissue. Finally, during remodeling, the body remodels the new tissue to form a scar.

      However, several factors can affect the wound healing process, including vascular disease, shock, sepsis, and jaundice. Additionally, some scars may develop problems, such as hypertrophic scars, which contain excessive amounts of collagen within the scar and may develop contractures. Keloid scars are another type of problematic scar that extends beyond the boundaries of the original injury and does not regress over time.

      Several drugs can also impair wound healing, including non-steroidal anti-inflammatory drugs, steroids, immunosuppressive agents, and anti-neoplastic drugs. Closure of the wound can occur through delayed primary closure or secondary closure, depending on the timing of the closure and the presence of granulation tissue.

      In summary, wound healing is a complex process that involves several stages, and several factors can affect the process and lead to problematic scars. Understanding the stages of wound healing and common problems with scars can help healthcare professionals provide better care for patients with wounds.

    • This question is part of the following fields:

      • General Principles
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  • Question 35 - A new drug is being trialled for joint pain and its pharmacology and...

    Incorrect

    • A new drug is being trialled for joint pain and its pharmacology and pharmacokinetics are being reviewed. A patient in their 40s receives drug X of 500mg strength with the initial plasma concentration being recorded as 8.0mg/L. Calculate the drug’s volume of distribution.

      60L
      6%
      65.5L
      4%
      62.5L
      83%
      64L
      6%
      63L
      1%

      In order to calculate volume of distribution you must be familiar with the equation.

      Vd = Dose/Plasma concentration

      Since the units here all related we don’t have to change anything but ensure that the units are compatible before plugging them into the formula. Here the drug dose was 500mg and the concentration was 8.0mg/L.
      500mg/8.0mg/L = 62.5L?

      Your Answer:

      Correct Answer: 62.5L

      Explanation:

      To determine the volume of distribution, one should be acquainted with the formula Vd = Dose/Plasma concentration. It is important to ensure that the units used are compatible before substituting them into the equation. For instance, if the drug dose is 500mg and the concentration is 8.0mg/L, the volume of distribution would be 62.5L.

      Understanding Volume of Distribution in Pharmacology

      The volume of distribution (VD) is a concept in pharmacology that refers to the theoretical volume that a drug would occupy to achieve the same concentration as it currently has in the blood plasma. The VD is used to determine how a drug is distributed in the body and can be classified as low, medium, or high. Low VD drugs are confined to the plasma, while medium VD drugs are distributed in the extracellular space, and high VD drugs are distributed in the tissues.

      Several factors influence the VD of a drug, including liver and renal failure, pregnancy, dehydration, large molecules, high plasma protein, hydrophilicity, and high charge. For instance, drugs with high plasma protein binding tend to have a low VD because they are confined to the plasma. On the other hand, drugs that are highly hydrophilic or charged tend to have a low VD because they cannot penetrate cell membranes.

      Examples of high VD drugs include tricyclic antidepressants, morphine, digoxin, phenytoin, chloroquine, and salicylates. These drugs are distributed widely in the body and can penetrate cell membranes. In contrast, low VD drugs include heparin, insulin, and warfarin, which are confined to the plasma due to their large size or high plasma protein binding. Understanding the VD of a drug is crucial in determining its pharmacokinetics and optimizing its therapeutic effects.

    • This question is part of the following fields:

      • General Principles
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  • Question 36 - Which of the following tumors is most likely to cause early para-aortic nodal...

    Incorrect

    • Which of the following tumors is most likely to cause early para-aortic nodal metastasis in younger patients?

      Your Answer:

      Correct Answer: Ovarian

      Explanation:

      The ovarian vessels directly branch from the aorta to supply ovarian tumours. Meanwhile, the internal and external iliac nodes are responsible for draining the cervix.

      Para-aortic Lymphadenopathy and its Association with Metastasis

      Para-aortic lymphadenopathy is a condition where the lymph nodes located near the aorta become enlarged due to the spread of cancer cells. This condition is commonly associated with the metastasis of cancer cells from various organs, including the testis, ovary, and uterine fundus. In these cases, the cancer cells spread to the para-aortic lymph nodes at an early stage of the disease.

      However, it is important to note that para-aortic nodal disease may also occur as a result of cancer cells spreading from other organs. In these cases, the para-aortic nodal disease represents a much later stage of the disease, as other nodal stations are involved earlier.

      Overall, para-aortic lymphadenopathy is a significant concern for individuals with cancer, as it can indicate the spread of cancer cells to other parts of the body. Early detection and treatment of para-aortic nodal disease can improve the chances of successful treatment and recovery.

    • This question is part of the following fields:

      • Haematology And Oncology
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  • Question 37 - What is the main role of the Golgi apparatus in eukaryotic cells? ...

    Incorrect

    • What is the main role of the Golgi apparatus in eukaryotic cells?

      Your Answer:

      Correct Answer: Process of proteins

      Explanation:

      The Golgi Apparatus, Cell Division, and Homeostasis

      The Golgi apparatus is a structure found in eukaryotic cells that consists of flattened membrane stacks. Its primary function is to modify proteins that have been synthesized in the rough endoplasmic reticulum, preparing them for secretion or transport within the cell. However, the Golgi apparatus is not directly involved in cell division, which is controlled by the nucleus.

      Cell homeostasis, on the other hand, is primarily maintained by membrane-embedded channels or proteins such as the sodium-potassium pump. This mechanism ensures that the cell’s internal environment remains stable. The sodium-potassium pump is an active transport mechanism that involves the binding of three intracellular sodium ions to the protein. Adenosine triphosphate (ATP) donates a phosphate group to the protein, which causes it to change shape and release the sodium ions out of the cell.

      The protein then accepts two extracellular potassium ions, and the donated phosphate group detaches, causing the protein to revert to its original shape. This allows the potassium ions to enter the cell, increasing the intracellular potassium concentration and decreasing the intracellular sodium concentration. This process is in contrast to the extracellular conditions.

      In summary, the Golgi apparatus modifies proteins for secretion or transport, while cell division is controlled by the nucleus. Cell homeostasis is maintained by membrane-embedded channels or proteins such as the sodium-potassium pump, which actively transports ions to stabilize the cell’s internal environment.

    • This question is part of the following fields:

      • Basic Sciences
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  • Question 38 - A 16-year-old girl arrives at the Emergency Department complaining of dizziness and pain...

    Incorrect

    • A 16-year-old girl arrives at the Emergency Department complaining of dizziness and pain in her right iliac fossa. She had taken a home pregnancy test the day before, which came back positive. After a diagnosis of ectopic pregnancy, the patient's condition worsens, and she undergoes an emergency salpingectomy. What is the most common site of fertilization in the excised structure?

      Your Answer:

      Correct Answer: Ampulla

      Explanation:

      Fertilisation typically takes place in the ampulla of the fallopian tube. Salpingectomy involves removing the fallopian tube and is often performed in cases of a ruptured ectopic pregnancy. It is rare for fertilisation to occur in the uterus, which is not removed during salpingectomy. The infundibulum, located closest to the ovary, is the third most common site of fertilisation, while the isthmus, the narrowest part of the fallopian tube, is the second most common site. The myometrium refers to the muscular wall of the uterus.

      Anatomy of the Uterus

      The uterus is a female reproductive organ that is located within the pelvis and is covered by the peritoneum. It is supplied with blood by the uterine artery, which runs alongside the uterus and anastomoses with the ovarian artery. The uterus is supported by various ligaments, including the central perineal tendon, lateral cervical, round, and uterosacral ligaments. The ureter is located close to the uterus, and injuries to the ureter can occur when there is pathology in the area.

      The uterus is typically anteverted and anteflexed in most women. Its topography can be visualized through imaging techniques such as ultrasound or MRI. Understanding the anatomy of the uterus is important for diagnosing and treating various gynecological conditions.

    • This question is part of the following fields:

      • Reproductive System
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  • Question 39 - A woman in her late 40s experiences kidney failure and receives a transplant....

    Incorrect

    • A woman in her late 40s experiences kidney failure and receives a transplant. However, she develops a fever and ceases urine output shortly after. Is hyperacute organ rejection the cause, and which cells are responsible for this reaction?

      Your Answer:

      Correct Answer: B Cells

      Explanation:

      Hyperacute organ rejection is mediated by B cells.

      The adaptive immune response involves several types of cells, including helper T cells, cytotoxic T cells, B cells, and plasma cells. Helper T cells are responsible for the cell-mediated immune response and recognize antigens presented by MHC class II molecules. They express CD4, CD3, TCR, and CD28 and are a major source of IL-2. Cytotoxic T cells also participate in the cell-mediated immune response and recognize antigens presented by MHC class I molecules. They induce apoptosis in virally infected and tumor cells and express CD8 and CD3. Both helper T cells and cytotoxic T cells mediate acute and chronic organ rejection.

      B cells are the primary cells of the humoral immune response and act as antigen-presenting cells. They also mediate hyperacute organ rejection. Plasma cells are differentiated from B cells and produce large amounts of antibody specific to a particular antigen. Overall, these cells work together to mount a targeted and specific immune response to invading pathogens or abnormal cells.

    • This question is part of the following fields:

      • General Principles
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  • Question 40 - A 25-year-old, biology student, with a history of insomnia, has approached their college...

    Incorrect

    • A 25-year-old, biology student, with a history of insomnia, has approached their college doctor with inquiries about a newly advertised medication for insomnia treatment. The medication boosts the synthesis of gamma-aminobutyric acid (GABA) from glutamate, resulting in a calming effect.

      What is the enzyme that the drug is mimicking?

      Your Answer:

      Correct Answer: Glutamate decarboxylase

      Explanation:

      The conversion of glutamate to GABA is catalyzed by glutamate decarboxylase. Other enzymes involved in this process include glutamate synthase, which converts glutamine to glutamate, glutamine synthetase, which converts glutamate to glutamine and vice versa, and 4-aminobutyrate transaminase, which converts GABA to succinate semialdehyde.

      Understanding GABA as the Principal Inhibitory Neurotransmitter of the Cortex

      GABA, or gamma-aminobutyric acid, is a crucial neurotransmitter that plays a significant role in regulating brain activity. It is considered the principal inhibitory neurotransmitter of the cortex, which means that it helps to reduce the activity of neurons in this region of the brain. This is important because excessive neuronal activity can lead to seizures, anxiety, and other neurological disorders.

      GABA is produced in a region of the brain called the substantia nigra pars reticulata. This area is responsible for regulating movement and is also involved in the production of dopamine, another important neurotransmitter. GABA is released by neurons in the cortex and binds to specific receptors on other neurons, which helps to reduce their activity.

      The importance of GABA in the brain cannot be overstated. It is involved in a wide range of functions, including sleep, anxiety, and mood regulation. It is also a target for many drugs used to treat neurological disorders, such as epilepsy and anxiety. Understanding the role of GABA in the brain is crucial for developing new treatments for these conditions and improving our overall understanding of brain function.

    • This question is part of the following fields:

      • General Principles
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  • Question 41 - A 49-year-old woman visits the clinic complaining of occasional palpitations over the last...

    Incorrect

    • A 49-year-old woman visits the clinic complaining of occasional palpitations over the last 7 days. The palpitations occur without any physical exertion and are not accompanied by chest pain. Upon examination, her heart appears to be functioning normally. An ECG is conducted, revealing indications of hyperkalaemia. What is an ECG indicator of hyperkalaemia?

      Your Answer:

      Correct Answer: Small or absent P waves

      Explanation:

      The presence of small or inverted T waves on an ECG can indicate hyperkalaemia, along with other signs such as absent or reduced P waves, broad and bizarre QRS complexes, and tall-tented T waves. In severe cases, hyperkalaemia can lead to asystole.

      Hyperkalaemia is a condition where there is an excess of potassium in the blood. The levels of potassium in the plasma are regulated by various factors such as aldosterone, insulin levels, and acid-base balance. When there is metabolic acidosis, hyperkalaemia can occur as hydrogen and potassium ions compete with each other for exchange with sodium ions across cell membranes and in the distal tubule. The ECG changes that can be seen in hyperkalaemia include tall-tented T waves, small P waves, widened QRS leading to a sinusoidal pattern, and asystole.

      There are several causes of hyperkalaemia, including acute kidney injury, drugs such as potassium sparing diuretics, ACE inhibitors, angiotensin 2 receptor blockers, spironolactone, ciclosporin, and heparin, metabolic acidosis, Addison’s disease, rhabdomyolysis, and massive blood transfusion. Foods that are high in potassium include salt substitutes, bananas, oranges, kiwi fruit, avocado, spinach, and tomatoes.

      It is important to note that beta-blockers can interfere with potassium transport into cells and potentially cause hyperkalaemia in renal failure patients. In contrast, beta-agonists such as Salbutamol are sometimes used as emergency treatment. Additionally, both unfractionated and low-molecular weight heparin can cause hyperkalaemia by inhibiting aldosterone secretion.

    • This question is part of the following fields:

      • Renal System
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  • Question 42 - A 58-year-old woman has a sigmoid colon resection in the Hartmans style, with...

    Incorrect

    • A 58-year-old woman has a sigmoid colon resection in the Hartmans style, with ligation of vessels near the colon. Which vessel will be responsible for directly supplying the rectal stump?

      Your Answer:

      Correct Answer: Superior rectal artery

      Explanation:

      The blood supply to the rectum is provided by the superior rectal artery, which may be affected if the IMA is ligated too high. However, in the case of the Hartmans procedure, the vessels were ligated near the bowel, indicating that the superior rectal artery was not compromised.

      Anatomy of the Rectum

      The rectum is a capacitance organ that measures approximately 12 cm in length. It consists of both intra and extraperitoneal components, with the transition from the sigmoid colon marked by the disappearance of the tenia coli. The extra peritoneal rectum is surrounded by mesorectal fat that contains lymph nodes, which are removed during rectal cancer surgery. The fascial layers that surround the rectum are important clinical landmarks, with the fascia of Denonvilliers located anteriorly and Waldeyers fascia located posteriorly.

      In males, the rectum is adjacent to the rectovesical pouch, bladder, prostate, and seminal vesicles, while in females, it is adjacent to the recto-uterine pouch (Douglas), cervix, and vaginal wall. Posteriorly, the rectum is in contact with the sacrum, coccyx, and middle sacral artery, while laterally, it is adjacent to the levator ani and coccygeus muscles.

      The superior rectal artery supplies blood to the rectum, while the superior rectal vein drains it. Mesorectal lymph nodes located superior to the dentate line drain into the internal iliac and then para-aortic nodes, while those located inferior to the dentate line drain into the inguinal nodes. Understanding the anatomy of the rectum is crucial for surgical procedures and the diagnosis and treatment of rectal diseases.

    • This question is part of the following fields:

      • Gastrointestinal System
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  • Question 43 - As a medical student working in the emergency department, you come across a...

    Incorrect

    • As a medical student working in the emergency department, you come across a 75-year-old man with a medical history of hypertension, dyslipidaemia, and atrial fibrillation. He was brought in by ambulance after collapsing at home. During the examination, you notice that he is unable to raise his right arm and has reduced sensation on the right side of his body. The consultant suspects that the patient is having a stroke and orders an urgent CT head.

      Upon reviewing the results, the consultant informs you that there is a significant area of ischaemia affecting the insula, somatosensory cortex, and part of the frontal cortex. Your task is to identify the artery that is most likely to be occluded by an infarct.

      Your Answer:

      Correct Answer: Left middle cerebral artery

      Explanation:

      The correct blood vessel supplying the frontal, temporal, and parietal lobes is the left middle cerebral artery. This is evident from the patient’s symptoms of right-sided loss of sensation and weakness, which are controlled by the contralateral somatosensory and motor cortex. The other options, such as the anterior spinal artery and the anterior cerebral arteries, are incorrect as they do not supply the brain or the specific areas affected in this patient.

      The Circle of Willis is an anastomosis formed by the internal carotid arteries and vertebral arteries on the bottom surface of the brain. It is divided into two halves and is made up of various arteries, including the anterior communicating artery, anterior cerebral artery, internal carotid artery, posterior communicating artery, and posterior cerebral arteries. The circle and its branches supply blood to important areas of the brain, such as the corpus striatum, internal capsule, diencephalon, and midbrain.

      The vertebral arteries enter the cranial cavity through the foramen magnum and lie in the subarachnoid space. They then ascend on the anterior surface of the medulla oblongata and unite to form the basilar artery at the base of the pons. The basilar artery has several branches, including the anterior inferior cerebellar artery, labyrinthine artery, pontine arteries, superior cerebellar artery, and posterior cerebral artery.

      The internal carotid arteries also have several branches, such as the posterior communicating artery, anterior cerebral artery, middle cerebral artery, and anterior choroid artery. These arteries supply blood to different parts of the brain, including the frontal, temporal, and parietal lobes. Overall, the Circle of Willis and its branches play a crucial role in providing oxygen and nutrients to the brain.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 44 - A 78-year-old ex-smoker comes to the clinic complaining of chest discomfort and shortness...

    Incorrect

    • A 78-year-old ex-smoker comes to the clinic complaining of chest discomfort and shortness of breath. He had a history of ST-elevation myocardial infarction 10 days ago, which was treated with thrombolysis. During the examination, a high-pitch holosystolic murmur is heard at the apex. The ECG shows widespread ST elevation. Unfortunately, the patient experiences cardiac arrest and passes away. What is the probable histological finding in his heart?

      Your Answer:

      Correct Answer: Macrophages and granulation tissue at margins

      Explanation:

      The histology findings of a myocardial infarction (MI) vary depending on the time elapsed since the event. Within the first 24 hours, there is evidence of early coagulative necrosis, neutrophils, wavy fibers, and hypercontraction of myofibrils. This stage is associated with a high risk of ventricular arrhythmia, heart failure, and cardiogenic shock.

      Between 1-3 days post-MI, there is extensive coagulative necrosis and an influx of neutrophils, which can lead to fibrinous pericarditis. From 3-14 days post-MI, macrophages and granulation tissue are present at the margins, and there is a high risk of complications such as free wall rupture (which can cause mitral regurgitation), papillary muscle rupture, and left ventricular pseudoaneurysm.

      After 2 weeks to several months, the scar tissue has contracted and is complete. This stage is associated with Dressler syndrome, heart failure, arrhythmias, and mural thrombus. It is important to note that the risk of complications decreases as time passes, but long-term management and monitoring are still necessary for patients who have experienced an MI.

      Myocardial infarction (MI) can lead to various complications, which can occur immediately, early, or late after the event. Cardiac arrest is the most common cause of death following MI, usually due to ventricular fibrillation. Cardiogenic shock may occur if a large part of the ventricular myocardium is damaged, and it is difficult to treat. Chronic heart failure may result from ventricular myocardium dysfunction, which can be managed with loop diuretics, ACE-inhibitors, and beta-blockers. Tachyarrhythmias, such as ventricular fibrillation and ventricular tachycardia, are common complications. Bradyarrhythmias, such as atrioventricular block, are more common following inferior MI. Pericarditis is common in the first 48 hours after a transmural MI, while Dressler’s syndrome may occur 2-6 weeks later. Left ventricular aneurysm and free wall rupture, ventricular septal defect, and acute mitral regurgitation are other complications that may require urgent medical attention.

    • This question is part of the following fields:

      • Cardiovascular System
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  • Question 45 - A neurologist is consulted for a patient who has displayed limited visual fields...

    Incorrect

    • A neurologist is consulted for a patient who has displayed limited visual fields in one eye during an examination. Upon conducting an MRI, the neurologist discovers a tumor in the right temporal lobe, near the border with the occipital region. What type of visual impairment is the patient most likely experiencing?

      Your Answer:

      Correct Answer: Left superior homonymous quadrantanopia

      Explanation:

      Temporal lobe lesions result in contralateral homonymous quadrantanopias, with damage to the Meyer’s loop and optic radiations causing this condition. The optic radiations receiving information from the superior quadrants are located more inferiorly while those from the inferior travel more superiorly. As the lesion is located in the lower part of the right temporal lobe near the occipital region, it is likely to affect the left superior quadrant. It is important to note that lesions on the temporal lobe correspond to superior quadrants rather than inferior, and damage to the right side of the brain affects the left visual field. Additionally, temporal lobe lesions cause quadrantanopias and not hemianopias.

      Understanding Visual Field Defects

      Visual field defects can occur due to various reasons, including lesions in the optic tract, optic radiation, or occipital cortex. A left homonymous hemianopia indicates a visual field defect to the left, which is caused by a lesion in the right optic tract. On the other hand, homonymous quadrantanopias can be categorized into PITS (Parietal-Inferior, Temporal-Superior) and can be caused by lesions in the inferior or superior optic radiations in the temporal or parietal lobes.

      When it comes to congruous and incongruous defects, the former refers to complete or symmetrical visual field loss, while the latter indicates incomplete or asymmetric visual field loss. Incongruous defects are caused by optic tract lesions, while congruous defects are caused by optic radiation or occipital cortex lesions. In cases where there is macula sparing, it is indicative of a lesion in the occipital cortex.

      Bitemporal hemianopia, on the other hand, is caused by a lesion in the optic chiasm. The type of defect can indicate the location of the compression, with an upper quadrant defect being more common in inferior chiasmal compression, such as a pituitary tumor, and a lower quadrant defect being more common in superior chiasmal compression, such as a craniopharyngioma.

      Understanding visual field defects is crucial in diagnosing and treating various neurological conditions. By identifying the type and location of the defect, healthcare professionals can provide appropriate interventions to improve the patient’s quality of life.

    • This question is part of the following fields:

      • Neurological System
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  • Question 46 - Which of the following is not secreted by the islets of Langerhans? ...

    Incorrect

    • Which of the following is not secreted by the islets of Langerhans?

      Your Answer:

      Correct Answer: Secretin

      Explanation:

      Mucosal cells in the duodenum and jejunum release secretin.

      Hormones Released from the Islets of Langerhans

      The islets of Langerhans in the pancreas are responsible for the production and secretion of several hormones that play a crucial role in regulating blood glucose levels. The beta cells in the islets of Langerhans are responsible for producing insulin, which accounts for 70% of the total secretions. Insulin helps to lower blood glucose levels by promoting the uptake of glucose by cells and tissues throughout the body.

      The alpha cells in the islets of Langerhans produce glucagon, which has the opposite effect of insulin. Glucagon raises blood glucose levels by stimulating the liver to release stored glucose into the bloodstream. The delta cells in the islets of Langerhans produce somatostatin, which helps to regulate the release of insulin and glucagon.

      Finally, the F cells in the islets of Langerhans produce pancreatic polypeptide, which plays a role in regulating pancreatic exocrine function and appetite. Together, these hormones work to maintain a delicate balance of blood glucose levels in the body.

    • This question is part of the following fields:

      • Endocrine System
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  • Question 47 - A 22-year-old university student with a history of primary sclerosing cholangitis presents to...

    Incorrect

    • A 22-year-old university student with a history of primary sclerosing cholangitis presents to the gastroenterologists with symptoms suggestive of ulcerative colitis. She has been experiencing bloody diarrhoea and fatigue for the past three months, with an average of seven bowel movements per day. Her medical history includes a childhood hepatitis A infection and an uncomplicated appendicectomy three years ago. She also has a family history of hepatocellular carcinoma.

      During examination, stage 1 haemorrhoids and a scar over McBurney's point are noted. Given her medical history, which condition warrants annual colonoscopy in this patient?

      Your Answer:

      Correct Answer: Primary sclerosing cholangitis

      Explanation:

      Annual colonoscopy is recommended for individuals who have both ulcerative colitis and PSC.

      Colorectal Cancer Risk in Ulcerative Colitis Patients

      Ulcerative colitis patients have a significantly higher risk of developing colorectal cancer compared to the general population. The risk is mainly related to chronic inflammation, and studies report varying rates. Unfortunately, patients with ulcerative colitis often experience delayed diagnosis, leading to a worse prognosis. Lesions may also be multifocal, further increasing the risk of cancer.

      Several factors increase the risk of colorectal cancer in ulcerative colitis patients, including disease duration of more than 10 years, pancolitis, onset before 15 years old, unremitting disease, and poor compliance to treatment. To manage this risk, colonoscopy surveillance is recommended, and the frequency of surveillance depends on the patient’s risk stratification.

      Patients with lower risk require a colonoscopy every five years, while those with intermediate risk require a colonoscopy every three years. Patients with higher risk require a colonoscopy every year. The risk stratification is based on factors such as the extent of colitis, the severity of active endoscopic/histological inflammation, the presence of post-inflammatory polyps, and family history of colorectal cancer. Primary sclerosing cholangitis or a family history of colorectal cancer in first-degree relatives aged less than 50 years also increase the risk of cancer. By following these guidelines, ulcerative colitis patients can receive appropriate surveillance and management to reduce their risk of developing colorectal cancer.

    • This question is part of the following fields:

      • Gastrointestinal System
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  • Question 48 - A 36-year-old male visits the GP after being diagnosed with Conn's syndrome, which...

    Incorrect

    • A 36-year-old male visits the GP after being diagnosed with Conn's syndrome, which causes excessive production of aldosterone. How will this affect the balance of sodium and potassium in his blood?

      Your Answer:

      Correct Answer: Increased sodium, decreased potassium

      Explanation:

      Hypertension, hypernatraemia, and hypokalemia are common symptoms of primary hyperaldosteronism.

      The adrenal gland produces aldosterone, which is responsible for regulating potassium levels. Its primary function is to increase sodium absorption and decrease potassium secretion in the distal tubules and collecting duct of the nephron. As a result, sodium levels increase while potassium levels decrease.

      Primary hyperaldosteronism is a condition characterized by hypertension, hypokalaemia, and alkalosis. It was previously believed that adrenal adenoma, also known as Conn’s syndrome, was the most common cause of this condition. However, recent studies have shown that bilateral idiopathic adrenal hyperplasia is responsible for up to 70% of cases. It is important to differentiate between the two causes as it determines the appropriate treatment. Adrenal carcinoma is an extremely rare cause of primary hyperaldosteronism.

      To diagnose primary hyperaldosteronism, the 2016 Endocrine Society recommends a plasma aldosterone/renin ratio as the first-line investigation. This test should show high aldosterone levels alongside low renin levels due to negative feedback from sodium retention caused by aldosterone. If the results are positive, a high-resolution CT abdomen and adrenal vein sampling are used to differentiate between unilateral and bilateral sources of aldosterone excess. If the CT is normal, adrenal venous sampling (AVS) can be used to distinguish between unilateral adenoma and bilateral hyperplasia.

      The management of primary hyperaldosteronism depends on the underlying cause. Adrenal adenoma is treated with surgery, while bilateral adrenocortical hyperplasia is managed with an aldosterone antagonist such as spironolactone. It is important to accurately diagnose and manage primary hyperaldosteronism to prevent complications such as cardiovascular disease and stroke.

    • This question is part of the following fields:

      • Endocrine System
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  • Question 49 - A 25-year-old male presents to his GP with recurrent episodes of haematuria. He...

    Incorrect

    • A 25-year-old male presents to his GP with recurrent episodes of haematuria. He reports having a sore throat and mild cough for the past three days. Upon examination, his urine dipstick is negative for leukocytes and nitrates. His vital signs are as follows: SpO2 99%, respiratory rate 16/min, blood pressure 140/90mmHg, heart rate 80bpm, and temperature 37.1ºC. The initial blood results show a Hb of 14.8 g/dL, platelets of 290 * 109/L, WBC of 14.9 * 109/L, Na+ of 138 mmol/L, K+ of 4.5 mmol/L, urea of 7.2 mmol/L, creatinine of 150 µmol/L, and CRP of 1.2 mg/L. What is the most likely mechanism responsible for his haematuria?

      Your Answer:

      Correct Answer: Immune complex deposition

      Explanation:

      The likely diagnosis for the man is IgA nephropathy, which is characterized by immune complex deposition in the glomerulus and recurrent macroscopic haematuria following an upper respiratory tract infection. Disseminated intravascular coagulation (DIC) caused by activation of the coagulation cascade and damage from toxins such as Shiga toxin in haemolytic uraemic syndrome are not responsible mechanisms for IgA nephropathy. Benign prostatic hypertrophy (BPH), which is caused by hypertrophy of prostatic cells, can also cause haematuria, but it is unlikely in this patient as it typically affects older men and presents with other urinary symptoms.

      Understanding IgA Nephropathy

      IgA nephropathy, also known as Berger’s disease, is the most common cause of glomerulonephritis worldwide. It typically presents as macroscopic haematuria in young people following an upper respiratory tract infection. The condition is thought to be caused by mesangial deposition of IgA immune complexes, and there is considerable pathological overlap with Henoch-Schonlein purpura (HSP). Histology shows mesangial hypercellularity and positive immunofluorescence for IgA and C3.

      Differentiating between IgA nephropathy and post-streptococcal glomerulonephritis is important. Post-streptococcal glomerulonephritis is associated with low complement levels and the main symptom is proteinuria, although haematuria can occur. There is typically an interval between URTI and the onset of renal problems in post-streptococcal glomerulonephritis.

      Management of IgA nephropathy depends on the severity of the condition. If there is isolated hematuria, no or minimal proteinuria, and a normal glomerular filtration rate (GFR), no treatment is needed other than follow-up to check renal function. If there is persistent proteinuria and a normal or only slightly reduced GFR, initial treatment is with ACE inhibitors. If there is active disease or failure to respond to ACE inhibitors, immunosuppression with corticosteroids may be necessary.

      The prognosis for IgA nephropathy varies. 25% of patients develop ESRF. Markers of good prognosis include frank haematuria, while markers of poor prognosis include male gender, proteinuria (especially > 2 g/day), hypertension, smoking, hyperlipidaemia, and ACE genotype DD.

      Overall, understanding IgA nephropathy is important for proper diagnosis and management of the condition. Proper management can help improve outcomes and prevent progression to ESRF.

    • This question is part of the following fields:

      • Renal System
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  • Question 50 - A 63-year-old woman is referred to haematology clinic by her GP due to...

    Incorrect

    • A 63-year-old woman is referred to haematology clinic by her GP due to complaints of fatigue, night sweats and fevers. Upon completion of all the required tests, she revisits the clinic to receive her results and is informed that she has the most prevalent type of adult leukemia.

      What is the most probable diagnosis?

      Your Answer:

      Correct Answer: Chronic lymphocytic leukaemia

      Explanation:

      Leukaemia is a type of cancer that affects the blood and bone marrow. There are two main types of leukaemia: acute and chronic. Acute leukaemia progresses quickly and requires immediate treatment, while chronic leukaemia progresses more slowly and may not require treatment for some time.

      There are also different subtypes of leukaemia based on the type of blood cell affected. Acute lymphocytic leukaemia is the most common type of leukaemia in children, while acute myeloid leukaemia is less common. In adults, chronic lymphocytic leukaemia is the most common type, followed by chronic myeloid leukaemia and acute myeloid leukaemia.

      Understanding Chronic Lymphocytic Leukaemia: Symptoms and Diagnosis

      Chronic lymphocytic leukaemia (CLL) is a type of cancer that affects the blood and bone marrow. It is caused by the abnormal growth of B-cells, a type of white blood cell. CLL is the most common form of leukaemia in adults and is often asymptomatic, meaning it may be discovered incidentally during routine blood tests. However, some patients may experience symptoms such as weight loss, anorexia, bleeding, infections, and lymphadenopathy.

      To diagnose CLL, doctors typically perform a full blood count to check for lymphocytosis, a condition where there is an abnormally high number of lymphocytes in the blood. Patients may also have anaemia or thrombocytopenia, which can occur due to bone marrow replacement or autoimmune hemolytic anaemia. A blood film may also be taken to look for smudge cells, which are abnormal lymphocytes that appear broken or fragmented.

      The key investigation for CLL diagnosis is immunophenotyping, which involves using a panel of antibodies specific for CD5, CD19, CD20, and CD23. This test helps to identify the type of lymphocyte involved in the cancer and can confirm the diagnosis of CLL. With early detection and proper treatment, patients with CLL can manage their symptoms and improve their quality of life.

    • This question is part of the following fields:

      • Haematology And Oncology
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SESSION STATS - PERFORMANCE PER SPECIALTY

General Principles (1/1) 100%
Clinical Sciences (2/2) 100%
Neurological System (2/3) 67%
Cardiovascular System (1/3) 33%
Endocrine System (1/1) 100%
Rheumatology (1/1) 100%
Gastrointestinal System (1/1) 100%
Passmed