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  • Question 1 - What does the term glycaemic index mean? ...

    Incorrect

    • What does the term glycaemic index mean?

      Your Answer: A measurement of how much glucose a food contains

      Correct Answer: A measurement of how rapidly the carbohydrate in the food enters the blood

      Explanation:

      The Glycaemic Index Method is a commonly used tool by dieticians and patients to determine the impact of different foods on blood glucose levels. This method involves calculating the area under a curve that shows the rise in blood glucose after consuming a test portion of food containing 50 grams of carbohydrate. The rationale behind using the GI index is that foods that cause a rapid and significant increase in blood glucose levels can lead to an increase in insulin production. This can put individuals at a higher risk of hyperinsulinaemia and weight gain.

      High GI foods are typically those that contain refined sugars and processed cereals, such as white bread and white rice. These foods can cause a rapid increase in blood glucose levels, leading to a surge in insulin production. On the other hand, low GI foods, such as vegetables, legumes, and beans, are less likely to cause a significant increase in blood glucose levels.

      Overall, the Glycaemic Index Method can be helpful in making informed food choices and managing blood glucose levels. By choosing low GI foods, individuals can reduce their risk of hyperinsulinaemia and weight gain, while still enjoying a healthy and balanced diet.

    • This question is part of the following fields:

      • Clinical Sciences
      7.3
      Seconds
  • Question 2 - A 45-year-old engineer who recently returned from working in the Nigerian oil industry...

    Correct

    • A 45-year-old engineer who recently returned from working in the Nigerian oil industry is experiencing a persistent flu-like illness, cough, unintended weight loss of 5 kilograms in 3 months, and a faint erythematous rash. During examination, enlarged cervical lymph nodes were observed. What is the most probable cause of his illness?

      Your Answer: HIV seroconversion illness

      Explanation:

      HIV Consideration for Patients Returning from Developing Countries

      Patients who have recently returned from developing countries, particularly sub-Saharan Africa, should always be considered for HIV infection. This is especially important if they are exhibiting symptoms of seroconversion, which is the period when the body is producing antibodies to fight the virus. It is crucial to consider HIV as a potential diagnosis in these cases, as early detection and treatment can greatly improve outcomes. A study published in the BMJ recommends that healthcare providers keep HIV in mind when evaluating patients who have recently traveled to developing countries. By doing so, they can help prevent the spread of the virus and provide appropriate care to those who are infected. It is important to note that HIV can be asymptomatic for years, so routine testing is also recommended for individuals who have traveled to high-risk areas.

    • This question is part of the following fields:

      • Infectious Diseases
      20.1
      Seconds
  • Question 3 - Mrs. Smith is a 75-year-old woman who presents to the emergency department with...

    Incorrect

    • Mrs. Smith is a 75-year-old woman who presents to the emergency department with progressive shortness of breath over the past 5 days. Last night she woke up suddenly because she couldn't catch her breath and developed a dry cough. Her breathing improved when she sat upright on the edge of her bed. She denies any chest pain, leg pain or fainting spells.

      Her past medical history includes a myocardial infarction 5 years ago for which she underwent a coronary artery bypass graft, hypertension and type 2 diabetes. She has been smoking for 30 years and doesn't drink any alcohol.

      What is the most likely diagnosis?

      Your Answer: Pulmonary embolism

      Correct Answer: Left-sided heart failure

      Explanation:

      The likely diagnosis for a patient experiencing paroxysmal nocturnal dyspnoea is left-sided heart failure. This symptom, which involves sudden waking at night due to shortness of breath, is a common feature of heart failure, particularly on the left side. Aortic dissection, myocardial infarction, and pulmonary embolism are unlikely diagnoses as they present with different symptoms. Right-sided heart failure is also an unlikely diagnosis as it presents with different features such as raised JVP, ankle oedema, and hepatomegaly.

      Features of Chronic Heart Failure

      Chronic heart failure is a condition that affects the heart’s ability to pump blood effectively. It is characterized by several features that can help in its diagnosis. Dyspnoea, or shortness of breath, is a common symptom of chronic heart failure. Patients may also experience coughing, which can be worse at night and accompanied by pink or frothy sputum. Orthopnoea, or difficulty breathing while lying down, and paroxysmal nocturnal dyspnoea, or sudden shortness of breath at night, are also common symptoms.

      Another feature of chronic heart failure is the presence of a wheeze, known as a cardiac wheeze. Patients may also experience weight loss, known as cardiac cachexia, which occurs in up to 15% of patients. However, this may be hidden by weight gained due to oedema. On examination, bibasal crackles may be heard, and signs of right-sided heart failure, such as a raised JVP, ankle oedema, and hepatomegaly, may be present.

      In summary, chronic heart failure is a condition that can be identified by several features, including dyspnoea, coughing, orthopnoea, paroxysmal nocturnal dyspnoea, wheezing, weight loss, bibasal crackles, and signs of right-sided heart failure. Early recognition and management of these symptoms can help improve outcomes for patients with chronic heart failure.

    • This question is part of the following fields:

      • Cardiovascular System
      47.3
      Seconds
  • Question 4 - A father brings his 14-year-old son into the Emergency Department, who he witnessed...

    Incorrect

    • A father brings his 14-year-old son into the Emergency Department, who he witnessed having a 'fit' 30 minutes ago. This occurred as his son was getting up from his chair. The father noticed some shaking of his son's arms, lasting approximately 10 minutes.

      His son has been very stressed with school projects over the past week, staying up late and often missing meals. His son's past medical and developmental history is non-significant.

      On examination, the son is alert and responsive.

      What are the associated factors with this condition?

      Your Answer: Spike and wave appearance on electroencephalogram

      Correct Answer: Short postictal period

      Explanation:

      The recovery from syncopal episodes is rapid and the postictal period is short. In contrast, seizures have a much longer postictal period. The stem suggests that the syncope may be due to exam stress and poor nutrition habits. One way to differentiate between seizures and syncope is by the length of the postictal period, with syncope having a quick recovery. Lip smacking is not associated with syncope, but rather with focal seizures of the temporal lobe. The 10-minute postictal period described in the stem is not consistent with a seizure.

      Epilepsy is a neurological condition that causes recurrent seizures. In the UK, around 500,000 people have epilepsy, and two-thirds of them can control their seizures with antiepileptic medication. While epilepsy usually occurs in isolation, certain conditions like cerebral palsy, tuberous sclerosis, and mitochondrial diseases have an association with epilepsy. It’s important to note that seizures can also occur due to other reasons like infection, trauma, or metabolic disturbance.

      Seizures can be classified into focal seizures, which start in a specific area of the brain, and generalised seizures, which involve networks on both sides of the brain. Patients who have had generalised seizures may experience biting their tongue or incontinence of urine. Following a seizure, patients typically have a postictal phase where they feel drowsy and tired for around 15 minutes.

      Patients who have had their first seizure generally undergo an electroencephalogram (EEG) and neuroimaging (usually a MRI). Most neurologists start antiepileptics following a second epileptic seizure. Antiepileptics are one of the few drugs where it is recommended that we prescribe by brand, rather than generically, due to the risk of slightly different bioavailability resulting in a lowered seizure threshold.

      Patients who drive, take other medications, wish to get pregnant, or take contraception need to consider the possible interactions of the antiepileptic medication. Some commonly used antiepileptics include sodium valproate, carbamazepine, lamotrigine, and phenytoin. In case of a seizure that doesn’t terminate after 5-10 minutes, medication like benzodiazepines may be administered to terminate the seizure. If a patient continues to fit despite such measures, they are said to have status epilepticus, which is a medical emergency requiring hospital treatment.

    • This question is part of the following fields:

      • Neurological System
      21.4
      Seconds
  • Question 5 - Where does spironolactone act in the kidney? ...

    Incorrect

    • Where does spironolactone act in the kidney?

      Your Answer: Descending limb of the loop of Henle

      Correct Answer: Distal convoluted tubule

      Explanation:

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

    • This question is part of the following fields:

      • General Principles
      19.6
      Seconds
  • Question 6 - Which one of the following decreases the production of renin? ...

    Incorrect

    • Which one of the following decreases the production of renin?

      Your Answer: Adrenaline

      Correct Answer: Beta-blockers

      Explanation:

      Renin and its Factors

      Renin is a hormone that is produced by juxtaglomerular cells. Its main function is to convert angiotensinogen into angiotensin I. There are several factors that can stimulate or reduce the secretion of renin.

      Factors that stimulate renin secretion include hypotension, which can cause reduced renal perfusion, hyponatremia, sympathetic nerve stimulation, catecholamines, and erect posture. On the other hand, there are also factors that can reduce renin secretion, such as beta-blockers and NSAIDs.

      It is important to understand the factors that affect renin secretion as it plays a crucial role in regulating blood pressure and fluid balance in the body. By knowing these factors, healthcare professionals can better manage and treat conditions related to renin secretion.

    • This question is part of the following fields:

      • Renal System
      24.4
      Seconds
  • Question 7 - One of the elderly patients at your general practice was recently hospitalized and...

    Incorrect

    • One of the elderly patients at your general practice was recently hospitalized and diagnosed with myeloma. It was discovered that they have severe chronic kidney disease. The patient comes in for an update on their condition. After reviewing their medications, you realize they are taking ramipril for hypertension, which is contraindicated in renal failure. What is the most accurate description of the effect of ACE inhibitors on glomerular filtration pressure?

      Your Answer: Vasodilation of the afferent arteriole

      Correct Answer: Vasodilation of the efferent arteriole

      Explanation:

      The efferent arteriole experiences vasodilation as a result of ACE inhibitors and ARBs, which inhibit the production of angiotensin II and block its receptors. This leads to a decrease in glomerular filtration pressure and rate, particularly in individuals with renal artery stenosis. On the other hand, the afferent arteriole remains dilated due to the presence of prostaglandins. NSAIDs, which inhibit COX-1 and COX-2, can cause vasoconstriction of the afferent arteriole and a subsequent decrease in glomerular filtration pressure. In healthy individuals, the afferent arteriole remains dilated while the efferent arteriole remains constricted to maintain a balanced glomerular pressure. The patient in the scenario has been diagnosed with myeloma, a disease that arises from the malignant transformation of B-cells and is characterized by bone infiltration, hypercalcaemia, anaemia, and renal impairment.

      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
      74.8
      Seconds
  • Question 8 - A 50-year-old man arrives at the emergency department with complaints of increasing fatigue,...

    Correct

    • A 50-year-old man arrives at the emergency department with complaints of increasing fatigue, malaise, and polyuria. He discloses that he had a deceased-donor kidney transplant 3 months ago. Upon conducting a urinalysis, the following results are obtained: positive for protein, negative for blood, glucose, leucocytes, and nitrites. The medical team suspects transplant rejection. Which type of cell is responsible for mediating this complication?

      Your Answer: Cytotoxic T cells

      Explanation:

      Cytotoxic T cells are responsible for both acute and chronic organ rejection. Acute rejection typically occurs within one week to three months after transplantation and is a type IV hypersensitivity reaction, which is cell-mediated. On the other hand, hyperacute rejection, which is a type II hypersensitivity reaction, is mediated by B cells and occurs within 24 hours of transplantation. Granulocytes, infiltrating macrophages, and plasma cells are not the primary drivers of acute organ rejection.

      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
      25.8
      Seconds
  • Question 9 - A 25-year-old woman presents to the gastrointestinal clinic with a history of abdominal...

    Incorrect

    • A 25-year-old woman presents to the gastrointestinal clinic with a history of abdominal bloating, diarrhoea, and fatigue for the past 6 months. She experiences severe cramps after most meals and struggles to focus on her work at the office.

      After conducting investigations, it is found that her tissue transglutaminases (TTG) are positive. What is a potential complication of the suspected underlying diagnosis?

      Your Answer: Sclerosing cholangitis

      Correct Answer: Hyposplenism

      Explanation:

      Hyposplenism is a possible complication of coeliac disease. The patient’s symptoms and positive tissue transglutaminases support the diagnosis of coeliac disease, which can lead to malabsorption of important nutrients like iron, folate, and vitamin B12. Hyposplenism may occur due to autoimmune processes and loss of lymphocyte recirculation caused by inflammation in the colon. However, hepatomegaly, pancreatitis, and polycythaemia are not associated with coeliac disease.

      Understanding Coeliac Disease

      Coeliac disease is an autoimmune disorder that affects approximately 1% of the UK population. It is caused by sensitivity to gluten, a protein found in wheat, barley, and rye. Repeated exposure to gluten leads to villous atrophy, which causes malabsorption. Coeliac disease is associated with various conditions, including dermatitis herpetiformis and autoimmune disorders such as type 1 diabetes mellitus and autoimmune hepatitis. It is strongly linked to HLA-DQ2 and HLA-DQ8.

      To diagnose coeliac disease, NICE recommends screening patients who exhibit signs and symptoms such as chronic or intermittent diarrhea, failure to thrive or faltering growth in children, persistent or unexplained gastrointestinal symptoms, prolonged fatigue, recurrent abdominal pain, sudden or unexpected weight loss, unexplained anemia, autoimmune thyroid disease, dermatitis herpetiformis, irritable bowel syndrome, type 1 diabetes, and first-degree relatives with coeliac disease.

      Complications of coeliac disease include anemia, hyposplenism, osteoporosis, osteomalacia, lactose intolerance, enteropathy-associated T-cell lymphoma of the small intestine, subfertility, and unfavorable pregnancy outcomes. In rare cases, it can lead to esophageal cancer and other malignancies.

      The diagnosis of coeliac disease is confirmed through a duodenal biopsy, which shows complete atrophy of the villi with flat mucosa and marked crypt hyperplasia, intraepithelial lymphocytosis, and dense mixed inflammatory infiltrate in the lamina propria. Treatment involves a lifelong gluten-free diet.

    • This question is part of the following fields:

      • Gastrointestinal System
      9.6
      Seconds
  • Question 10 - A 24-year-old man visits his GP clinic and requests a referral to a...

    Incorrect

    • A 24-year-old man visits his GP clinic and requests a referral to a plastic surgeon. He is worried that his ears are too large compared to his face. This has caused him to become reclusive and he has lost his employment. Upon examination, his ears seem to be of normal size. What is the most suitable term for this conduct?

      Your Answer: Hypochondriasis

      Correct Answer: Dysmorphophobia

      Explanation:

      Understanding Body Dysmorphic Disorder

      Body dysmorphic disorder, also known as dysmorphophobia, is a mental health condition that affects a person’s perception of their physical appearance. Individuals with this disorder have a distorted body image, which causes them to obsess over perceived flaws or defects in their appearance. Even if there is only a slight physical abnormality, the person’s concern is excessive and can lead to significant distress or impairment in their daily life.

      According to the Diagnostic and Statistical Manual (DSM) IV criteria, the preoccupation with the imagined defect must cause clinically significant distress or impairment in social, occupational, or other important areas of functioning. It is important to note that this preoccupation is not better accounted for by another mental disorder, such as dissatisfaction with body shape and size in Anorexia Nervosa.

      Body dysmorphic disorder can have a significant impact on a person’s mental health and quality of life. It is important for individuals who may be experiencing symptoms of this disorder to seek professional help from a mental health provider. With proper treatment, individuals with body dysmorphic disorder can learn to manage their symptoms and improve their overall well-being.

    • This question is part of the following fields:

      • Psychiatry
      14.8
      Seconds
  • Question 11 - A 22-year-old man suffers a depressed skull fracture at the vertex after being...

    Incorrect

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

      Your Answer: Inferior sagittal sinus

      Correct Answer: Superior sagittal sinus

      Explanation:

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

      Overview of Cranial Venous Sinuses

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

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

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

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

    • This question is part of the following fields:

      • Neurological System
      70
      Seconds
  • Question 12 - As a doctor on a 4-month placement in intensive care, you admit a...

    Incorrect

    • As a doctor on a 4-month placement in intensive care, you admit a 32-year-old man following a closed head injury sustained in a road traffic accident. The patient has no past medical history and initially presents with a Glasgow coma score of 14/15 and no focal neurological deficit. Invasive monitoring is undertaken, and his heart rate, blood pressure, and intracranial pressure are normal. He is started on maintenance intravenous fluids.

      However, a few hours later, the patient becomes agitated and confused, and his Glasgow coma score drops to 11/15. His observations reveal a regular heart rate of 101 beats per minute, a blood pressure of 161/89 mmHg, and an intracranial pressure of 18 mmHg. Which pathophysiological changes could explain his clinical deterioration and hypertension?

      Your Answer: Fall in cardiac output causing cerebral hypoxia

      Correct Answer: Rise in intracranial pressure causing fall in cerebral perfusion pressure

      Explanation:

      When intracranial pressure (ICP) rises rapidly, it can lead to a decrease in cerebral perfusion pressure (CPP). This can occur in individuals with head injuries, as seen in the scenario where a patient’s Glasgow coma score dropped from 14/15 to 11/15 and they became agitated. The patient’s ICP also increased to 18 mmHg, likely due to brain swelling or a hematoma. The decrease in CPP can cause hypoperfusion and hypoxia in normal brain tissue, leading to neurological deterioration. CPP is calculated by subtracting ICP from mean arterial pressure. As a result of the decrease in CPP, the body may respond by increasing mean arterial pressure, resulting in hypertension in the patient.

      Understanding Cerebral Perfusion Pressure

      Cerebral perfusion pressure (CPP) refers to the pressure gradient that drives blood flow to the brain. It is a crucial factor in maintaining optimal cerebral perfusion, which is tightly regulated by the body. Any sudden increase in CPP can lead to a rise in intracranial pressure (ICP), while a decrease in CPP can result in cerebral ischemia. To calculate CPP, one can subtract the ICP from the mean arterial pressure.

      In cases of trauma, it is essential to carefully monitor and control CPP. This may require invasive methods to measure both ICP and mean arterial pressure (MAP). By doing so, healthcare professionals can ensure that the brain receives adequate blood flow and oxygenation, which is vital for optimal brain function. Understanding CPP is crucial in managing traumatic brain injuries and other conditions that affect cerebral perfusion.

    • This question is part of the following fields:

      • Neurological System
      17.3
      Seconds
  • Question 13 - Which Korotkoff sound indicates that the diastolic pressure has been reached during blood...

    Correct

    • Which Korotkoff sound indicates that the diastolic pressure has been reached during blood pressure measurement?

      Your Answer: Fifth

      Explanation:

      Korotkoff Sounds

      Korotkoff sounds are the sounds heard when taking blood pressure readings. There are five phases of Korotkoff sounds, each indicating different stages of blood pressure. The first phase is a tapping sound, which indicates the systolic pressure. The second phase is a swooshing sound or murmurs. The third phase is a crisp tapping sound, while the fourth phase is a muffled, blowing sound. The fifth and final phase is silence.

      Older textbooks used to state that the fourth Korotkoff sound indicate diastolic pressure, but now the fifth sound is used preferentially. To take a blood pressure reading, the cuff is inflated and then slowly reduced. The first tapping sound heard is the systolic pressure. The cuff is then further deflated until silence is heard, which indicates the diastolic pressure. Korotkoff sounds is important for accurate blood pressure readings and proper diagnosis and treatment of hypertension.

    • This question is part of the following fields:

      • Clinical Sciences
      16.8
      Seconds
  • Question 14 - A randomized, double-blinded clinical trial was conducted to evaluate the effect of a...

    Incorrect

    • A randomized, double-blinded clinical trial was conducted to evaluate the effect of a new anti-inflammatory drug on the pain relief of patients with osteoarthritis. A total of 200 patients with osteoarthritis were randomly assigned to the drug or placebo group. For the study, 100 patients were assigned to each group. The two groups were then followed for six months for the development of adverse effects. Severe gastrointestinal bleeding was reported as a rare side effect of the drug therapy, but the difference between the two groups was not statistically significant (p=0.08). The same side effect was reported in several small clinical trials of this drug (p=0.05-0.10).

      What is the most likely reason for the failure to detect a significant statistical difference in the occurrence of gastrointestinal bleeding between the treatment and placebo groups?

      Your Answer: Attrition bias

      Correct Answer: Small sample size

      Explanation:

      A larger sample size can enhance the power of a study and reduce the likelihood of type II error. Power refers to the ability to detect a difference in the outcome of interest between two groups, if such a difference exists. With a bigger sample size, the study’s power to detect a difference increases, and the p-value can reach statistical significance.
      Attrition bias is a systematic error that arises from unequal loss of participants in a randomized controlled trial. However, since patients are not lost to follow-up in this study design, the likelihood of attrition bias is low.
      The Hawthorne effect is a type of reactivity where individuals modify their behavior in response to being observed. This effect does not occur in double-blinded randomized clinical trials.
      Double-blinding techniques can reduce the potential for observer’s bias.
      Increasing the follow-up period may not necessarily increase the power of the study, as side effects can occur in susceptible individuals relatively early after starting the therapy.

      Understanding the Concept of Power in Research Studies

      Power is a statistical concept that refers to the probability of correctly rejecting the null hypothesis when it is false. In other words, it is the ability of a study to detect a clinically meaningful difference or effect. The value of power ranges from 0 to 1, with 0 indicating 0% and 1 indicating 100%. It is often expressed as 1 – beta, where beta is the probability of a Type II error. A power of 0.80 is generally considered the minimum acceptable level.

      Several factors influence the power of a study, including sample size, meaningful effect size, and significance level. Larger sample sizes lead to more accurate parameter estimations and increase the study’s ability to detect a significant effect. The meaningful effect size is determined at the beginning of the study and represents the size of the difference between two means that would lead to the rejection of the null hypothesis. Finally, the significance level, also known as the alpha level, is the probability of a Type I error. Understanding the concept of power is crucial in determining the appropriate sample size and designing a study that can accurately detect meaningful differences or effects.

    • This question is part of the following fields:

      • General Principles
      23.8
      Seconds
  • Question 15 - As a medical student in a cardiology clinic, you encounter a 54-year-old woman...

    Incorrect

    • As a medical student in a cardiology clinic, you encounter a 54-year-old woman who has been diagnosed with atrial fibrillation by her GP after experiencing chest pain for 12 hours. She informs you that she had a blood clot in her early 30s following lower limb surgery and was previously treated with warfarin. Her CHA2DS2‑VASc score is 3. What is the first-line anticoagulant recommended to prevent future stroke in this patient?

      Your Answer: Warfarin

      Correct Answer: Edoxaban

      Explanation:

      According to the 2021 NICE guidelines on preventing stroke in individuals with atrial fibrillation, DOACs should be the first-line anticoagulant therapy offered. The correct answer is ‘edoxaban’. ‘Aspirin’ is not appropriate for managing atrial fibrillation as it is an antiplatelet agent. ‘Low molecular weight heparin’ and ‘unfractionated heparin’ are not recommended for long-term anticoagulation in this case as they require subcutaneous injections.

      Atrial fibrillation (AF) is a condition that requires careful management, including the use of anticoagulation therapy. The latest guidelines from NICE recommend assessing the need for anticoagulation in all patients with a history of AF, regardless of whether they are currently experiencing symptoms. The CHA2DS2-VASc scoring system is used to determine the most appropriate anticoagulation strategy, with a score of 2 or more indicating the need for anticoagulation. However, it is important to ensure a transthoracic echocardiogram has been done to exclude valvular heart disease, which is an absolute indication for anticoagulation.

      When considering anticoagulation therapy, doctors must also assess the patient’s bleeding risk. NICE recommends using the ORBIT scoring system to formalize this risk assessment, taking into account factors such as haemoglobin levels, age, bleeding history, renal impairment, and treatment with antiplatelet agents. While there are no formal rules on how to act on the ORBIT score, individual patient factors should be considered. The risk of bleeding increases with a higher ORBIT score, with a score of 4-7 indicating a high risk of bleeding.

      For many years, warfarin was the anticoagulant of choice for AF. However, the development of direct oral anticoagulants (DOACs) has changed this. DOACs have the advantage of not requiring regular blood tests to check the INR and are now recommended as the first-line anticoagulant for patients with AF. The recommended DOACs for reducing stroke risk in AF are apixaban, dabigatran, edoxaban, and rivaroxaban. Warfarin is now used second-line, in patients where a DOAC is contraindicated or not tolerated. Aspirin is not recommended for reducing stroke risk in patients with AF.

    • This question is part of the following fields:

      • Cardiovascular System
      28.8
      Seconds
  • Question 16 - An 80-year-old man arrives at the emergency department complaining of chest pain, sweating,...

    Incorrect

    • An 80-year-old man arrives at the emergency department complaining of chest pain, sweating, and nausea. His ECG reveals ST elevation. Which phase of the cardiac action potential does this correspond to? The ST segment of the ECG represents a period of sluggish calcium influx in the cardiac action potential.

      Your Answer: Phase 3

      Correct Answer: Phase 2

      Explanation:

      The ST segment in the ECG is caused by the slow influx of calcium during phase 2 of the cardiac action potential. Understanding the cardiac action potential is important for interpreting the electrical activity of the heart as reflected in the ECG waveform. The QRS complex represents rapid depolarisation, the ST segment represents the plateau phase, and the T wave represents repolarisation.

      Understanding the Cardiac Action Potential and Conduction Velocity

      The cardiac action potential is a series of electrical events that occur in the heart during each heartbeat. It is responsible for the contraction of the heart muscle and the pumping of blood throughout the body. The action potential is divided into five phases, each with a specific mechanism. The first phase is rapid depolarization, which is caused by the influx of sodium ions. The second phase is early repolarization, which is caused by the efflux of potassium ions. The third phase is the plateau phase, which is caused by the slow influx of calcium ions. The fourth phase is final repolarization, which is caused by the efflux of potassium ions. The final phase is the restoration of ionic concentrations, which is achieved by the Na+/K+ ATPase pump.

      Conduction velocity is the speed at which the electrical signal travels through the heart. The speed varies depending on the location of the signal. Atrial conduction spreads along ordinary atrial myocardial fibers at a speed of 1 m/sec. AV node conduction is much slower, at 0.05 m/sec. Ventricular conduction is the fastest in the heart, achieved by the large diameter of the Purkinje fibers, which can achieve velocities of 2-4 m/sec. This allows for a rapid and coordinated contraction of the ventricles, which is essential for the proper functioning of the heart. Understanding the cardiac action potential and conduction velocity is crucial for diagnosing and treating heart conditions.

    • This question is part of the following fields:

      • Cardiovascular System
      12.1
      Seconds
  • Question 17 - Which one of the following does not result in the relaxation of the...

    Incorrect

    • Which one of the following does not result in the relaxation of the lower esophageal sphincter?

      Your Answer: Botulinum toxin type A

      Correct Answer: Metoclopramide

      Explanation:

      Metoclopramide directly causes contraction of the smooth muscle of the LOS.

      Peristalsis: The Movement of Food Through the Digestive System

      Peristalsis is the process by which food is moved through the digestive system. Circular smooth muscle contracts behind the food bolus, while longitudinal smooth muscle propels the food through the oesophagus. Primary peristalsis spontaneously moves the food from the oesophagus into the stomach, taking about 9 seconds. Secondary peristalsis occurs when food does not enter the stomach, and stretch receptors are stimulated to cause peristalsis.

      In the small intestine, peristalsis waves slow to a few seconds and cause a mixture of chyme. In the colon, three main types of peristaltic activity are recognised. Segmentation contractions are localised contractions in which the bolus is subjected to local forces to maximise mucosal absorption. Antiperistaltic contractions towards the ileum are localised reverse peristaltic waves to slow entry into the colon and maximise absorption. Mass movements are migratory peristaltic waves along the entire colon to empty the organ prior to the next ingestion of a food bolus.

      Overall, peristalsis is a crucial process in the digestive system that ensures food is moved efficiently through the body.

    • This question is part of the following fields:

      • Gastrointestinal System
      22
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  • Question 18 - Which of these nerves passes through the greater and lesser sciatic foramina? ...

    Incorrect

    • Which of these nerves passes through the greater and lesser sciatic foramina?

      Your Answer: Posterior cutaneous nerve of the thigh

      Correct Answer: Pudendal nerve

      Explanation:

      The structures passing through the lesser and greater sciatic foramina, from medial to lateral, are the pudendal nerve, internal pudendal artery, and nerve to obturator internus. The pudendal nerve originates from the ventral rami of the second, third, and fourth sacral nerves and passes through the greater sciatic foramen before crossing the spine of the ischium and reentering the pelvis through the lesser sciatic foramen. It gives off the inferior rectal nerves and terminates into the perineal nerve and the dorsal nerve of the penis or clitoris.

      The Greater Sciatic Foramen and its Contents

      The greater sciatic foramen is a space in the pelvis that is bounded by various ligaments and bones. It serves as a passageway for several important structures, including nerves and blood vessels. The piriformis muscle is a landmark for identifying these structures as they pass through the sciatic notch. Above the piriformis muscle, the superior gluteal vessels can be found, while below it are the inferior gluteal vessels, the sciatic nerve (which passes through it in only 10% of cases), and the posterior cutaneous nerve of the thigh.

      The boundaries of the greater sciatic foramen include the greater sciatic notch of the ilium, the sacrotuberous ligament, the sacrospinous ligament, and the ischial spine. The anterior sacroiliac ligament forms the superior boundary. Structures passing through the greater sciatic foramen include the pudendal nerve, the internal pudendal artery, and the nerve to the obturator internus.

      In contrast, the lesser sciatic foramen is a smaller space that contains the tendon of the obturator internus, the pudendal nerve, the internal pudendal artery and vein, and the nerve to the obturator internus. Understanding the contents and boundaries of these foramina is important for clinicians who may need to access or avoid these structures during surgical procedures or other interventions.

    • This question is part of the following fields:

      • Musculoskeletal System And Skin
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  • Question 19 - A 32-year-old woman injures her sympathetic trunk and experiences Horner's syndrome. When sympathetic...

    Incorrect

    • A 32-year-old woman injures her sympathetic trunk and experiences Horner's syndrome. When sympathetic pathways are damaged, Horner's syndrome can occur. Which receptors are associated with her symptoms?

      Your Answer: Muscarinic acetylcholine receptors to the salivary glands

      Correct Answer: Muscarinic acetylcholine receptors of sudomotor neurons to the sweat gland

      Explanation:

      Acetylcholine is exclusively present in the postganglionic sympathetic fibers that lead to sweat glands.

      Although muscarinic receptors can be activated by the vagus nerve to the heart, this is a component of the parasympathetic nervous system.

      Muscarinic acetylcholine receptors in the salivary glands and the eye are both instances of muscarinic acetylcholine receptors in the parasympathetic nervous system.

      The neuromuscular junction employs nicotinic acetylcholine receptors, but this is not a part of the sympathetic nervous system.

      Acetylcholine (ACh) is a crucial neurotransmitter in the somatic nervous system and plays a significant role in the autonomic nervous system. It is the primary neurotransmitter in all pre- and postganglionic parasympathetic neurons, all preganglionic sympathetic neurons, and postganglionic sympathetic fibers, including sudomotor neurons that regulate sweat glands. Acetylcholinesterase is an enzyme that breaks down acetylcholine. In conditions such as myasthenia gravis, where there is a deficiency of functioning acetylcholine receptors, acetylcholinesterase inhibitors are used.

      In the central nervous system, acetylcholine is synthesized in the basal nucleus of Meynert. Alzheimer’s disease is associated with decreased levels of acetylcholine in the basal nucleus of Meynert. Therefore, acetylcholine plays a crucial role in the functioning of the nervous system, and its deficiency can lead to various neurological disorders.

    • This question is part of the following fields:

      • General Principles
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  • Question 20 - A 12-year-old girl, previously healthy, presents to the emergency department with symptoms of...

    Incorrect

    • A 12-year-old girl, previously healthy, presents to the emergency department with symptoms of nausea, vomiting, and confusion. The patient's father reports his child appearing fatigued, and having increased thirst and urinary frequency over the past few days. Upon laboratory analysis, the patient's serum glucose is found to be 25 mmol/L and urinalysis is positive for ketones. The medical team initiates fluid resuscitation and insulin therapy.

      What electrolyte changes are anticipated following the treatment of this patient?

      Your Answer:

      Correct Answer: Decrease in potassium levels

      Explanation:

      The Na+/K+ ATPase pump is stimulated by insulin, leading to a decrease in serum potassium levels. This effect is particularly relevant in patients with diabetic ketoacidosis, who experience insulin deficiency and hyperkalemia. It is important to monitor serum potassium levels closely during the management of diabetic ketoacidosis to avoid the potential complications of hypokalemia. Insulin does not cause a decrease in sodium levels, and its effects on calcium and phosphate homeostasis are minimal. The resolution of ketoacidosis with insulin and fluids will result in an increase in serum bicarbonate levels back to normal range.

      Insulin is a hormone produced by the pancreas that plays a crucial role in regulating the metabolism of carbohydrates and fats in the body. It works by causing cells in the liver, muscles, and fat tissue to absorb glucose from the bloodstream, which is then stored as glycogen in the liver and muscles or as triglycerides in fat cells. The human insulin protein is made up of 51 amino acids and is a dimer of an A-chain and a B-chain linked together by disulfide bonds. Pro-insulin is first formed in the rough endoplasmic reticulum of pancreatic beta cells and then cleaved to form insulin and C-peptide. Insulin is stored in secretory granules and released in response to high levels of glucose in the blood. In addition to its role in glucose metabolism, insulin also inhibits lipolysis, reduces muscle protein loss, and increases cellular uptake of potassium through stimulation of the Na+/K+ ATPase pump.

    • This question is part of the following fields:

      • Endocrine System
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  • Question 21 - A 26 year old female presents to the emergency department with hand tingling...

    Incorrect

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

      Your Answer:

      Correct Answer: Ulnar nerve

      Explanation:

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

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

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

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

    • This question is part of the following fields:

      • Neurological System
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  • Question 22 - A 65-year-old man with uncontrolled diabetes complains of severe otalgia and headaches. During...

    Incorrect

    • A 65-year-old man with uncontrolled diabetes complains of severe otalgia and headaches. During examination, granulation tissue is observed in the external auditory meatus. What is the probable causative agent of the infection?

      Your Answer:

      Correct Answer: Pseudomonas aeruginosa

      Explanation:

      The primary cause of malignant otitis externa is typically Pseudomonas aeruginosa. Symptoms of this condition include intense pain, headaches, and the presence of granulation tissue in the external auditory meatus. Individuals with diabetes mellitus are at a higher risk for developing this condition.

      Malignant Otitis Externa: A Rare but Serious Infection

      Malignant otitis externa is a type of ear infection that is uncommon but can be serious. It is typically found in individuals who are immunocompromised, with 90% of cases occurring in diabetics. The infection starts in the soft tissues of the external auditory meatus and can progress to involve the soft tissues and bony ear canal, eventually leading to temporal bone osteomyelitis.

      Key features in the patient’s history include diabetes or immunosuppression, severe and persistent ear pain, temporal headaches, and purulent otorrhea. In some cases, patients may also experience dysphagia, hoarseness, and facial nerve dysfunction.

      Diagnosis is typically done through a CT scan, and non-resolving otitis externa with worsening pain should be referred urgently to an ENT specialist. Treatment involves intravenous antibiotics that cover pseudomonal infections.

      In summary, malignant otitis externa is a rare but serious infection that requires prompt diagnosis and treatment. Patients with diabetes or immunosuppression should be particularly vigilant for symptoms and seek medical attention if they experience persistent ear pain or other related symptoms.

    • This question is part of the following fields:

      • Respiratory System
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  • Question 23 - A 16-year-old boy presents to his GP with a 5-month history of passing...

    Incorrect

    • A 16-year-old boy presents to his GP with a 5-month history of passing frequent watery diarrhoea, up to 6 times a day. He reports occasional passage of mucus mixed with his stool and has experienced a weight loss of around 9kg. An endoscopy and biopsy are performed, revealing evidence of granuloma formation.

      What is the probable diagnosis?

      Your Answer:

      Correct Answer: Crohn’s disease

      Explanation:

      The presence of granulomas in the gastrointestinal tract is a key feature of Crohn’s disease, which is a chronic inflammatory condition that can affect any part of the digestive system. The combination of granulomas and clinical history is highly indicative of this condition.

      Coeliac disease, on the other hand, is an autoimmune disorder triggered by gluten consumption that causes villous atrophy and malabsorption. However, it does not involve the formation of granulomas.

      Colonic tuberculosis, caused by Mycobacterium tuberculosis, is another granulomatous condition that affects the ileocaecal valve. However, the granulomas in this case are caseating with necrosis, and colonic tuberculosis is much less common than Crohn’s disease.

      Endoscopy and biopsy are not necessary for diagnosing irritable bowel syndrome, as they are primarily used to rule out other conditions. Biopsies in irritable bowel syndrome would not reveal granuloma formation.

      Ulcerative colitis, another inflammatory bowel disease, is characterized by crypt abscesses, pseudopolyps, and mucosal ulceration that can cause rectal bleeding. However, granulomas are not present in this condition.

      Inflammatory bowel disease (IBD) is a condition that includes two main types: Crohn’s disease and ulcerative colitis. Although they share many similarities in terms of symptoms, diagnosis, and treatment, there are some key differences between the two. Crohn’s disease is characterized by non-bloody diarrhea, weight loss, upper gastrointestinal symptoms, mouth ulcers, perianal disease, and a palpable abdominal mass in the right iliac fossa. On the other hand, ulcerative colitis is characterized by bloody diarrhea, abdominal pain in the left lower quadrant, tenesmus, gallstones, and primary sclerosing cholangitis. Complications of Crohn’s disease include obstruction, fistula, and colorectal cancer, while ulcerative colitis has a higher risk of colorectal cancer than Crohn’s disease. Pathologically, Crohn’s disease lesions can be seen anywhere from the mouth to anus, while ulcerative colitis inflammation always starts at the rectum and never spreads beyond the ileocaecal valve. Endoscopy and radiology can help diagnose and differentiate between the two types of IBD.

    • This question is part of the following fields:

      • Gastrointestinal System
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  • Question 24 - A couple in their late 30s come to the clinic seeking information about...

    Incorrect

    • A couple in their late 30s come to the clinic seeking information about the risk of their three children inheriting Huntington's disease. The husband has recently been diagnosed with the disease, while the wife is not affected. What is the likelihood, expressed as a percentage, that their children will inherit the disease?

      Your Answer:

      Correct Answer: 50%

      Explanation:

      Huntington’s Disease

      Huntington’s disease is a genetic disorder that typically appears later in life and is characterized by symptoms such as chorea, cognitive decline, and personality changes. It is an autosomal dominant disease, meaning that there is a 50% chance of passing it on to offspring. If the gene is inherited from an unaffected parent, the child will not be affected. This is different from autosomal recessive inheritance, where both parents must pass on the gene for it to affect their children.

      The disease is caused by an increase in the length of a repeating trinucleotide sequence (CAG) in the Huntington protein. This sequence can change in length through generations, and longer sequences are associated with earlier onset of symptoms (genetic anticipation). Since Huntington’s disease usually presents itself after people have already started their families, there are many issues associated with genetic testing.

    • This question is part of the following fields:

      • Basic Sciences
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  • Question 25 - After complaining of increasing irritability, difficulty concentrating and pain and weakness in his...

    Incorrect

    • After complaining of increasing irritability, difficulty concentrating and pain and weakness in his limbs, a 45-year-old patient with a history of alcoholism is sent for blood tests. The results reveal a vitamin deficiency and the general practitioner explains he has a condition called beriberi. Which vitamin is this patient deficient in?

      Your Answer:

      Correct Answer: Thiamine (vitamin B1)

      Explanation:

      The Importance of Vitamin B1 (Thiamine) in the Body

      Vitamin B1, also known as thiamine, is a water-soluble vitamin that belongs to the B complex group. It plays a crucial role in the body as one of its phosphate derivatives, thiamine pyrophosphate (TPP), acts as a coenzyme in various enzymatic reactions. These reactions include the catabolism of sugars and amino acids, such as pyruvate dehydrogenase complex, alpha-ketoglutarate dehydrogenase complex, and branched-chain amino acid dehydrogenase complex.

      Thiamine deficiency can lead to clinical consequences, particularly in highly aerobic tissues like the brain and heart. The brain can develop Wernicke-Korsakoff syndrome, which presents symptoms such as nystagmus, ophthalmoplegia, and ataxia. Meanwhile, the heart can develop wet beriberi, which causes dilated cardiomyopathy. Other conditions associated with thiamine deficiency include dry beriberi, which leads to peripheral neuropathy, and Korsakoff’s syndrome, which causes amnesia and confabulation.

      The primary causes of thiamine deficiency are alcohol excess and malnutrition. Alcoholics are routinely recommended to take thiamine supplements to prevent deficiency. Overall, thiamine is an essential vitamin that plays a vital role in the body’s metabolic processes.

    • This question is part of the following fields:

      • General Principles
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  • Question 26 - A 67-year-old man is brought to the emergency department after a fall and...

    Incorrect

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

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

      Your Answer:

      Correct Answer: Destruction of islets of Langerhans cells

      Explanation:

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

      Understanding Chronic Pancreatitis

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

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

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

    • This question is part of the following fields:

      • Gastrointestinal System
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  • Question 27 - A 12-year-old girl is experiencing intense pain around her belly button that is...

    Incorrect

    • A 12-year-old girl is experiencing intense pain around her belly button that is spreading to her right iliac fossa. She has a fever and is vomiting on and off. The medical team has decided to perform a laparoscopic removal of her appendix. Can you identify the most frequent location of the appendix in the pelvis?

      Your Answer:

      Correct Answer: Retrocaecal

      Explanation:

      Anatomy of the Appendix

      The appendix is a tube that is approximately 10 cm long and can be found in different positions in the body depending on the individual. It is most commonly located behind the caecum, which is retrocaecal, in about 65% of people. However, it can also be found in the pelvic area in around 30% of individuals. Other variations include being located below the caecum, which is subcaecal, or in front of the terminal ileum, which is pre-ileal. Additionally, it can be found behind the ileum, which is post-ileal. The position of the appendix can vary greatly from person to person, and it is important for medical professionals to be aware of these variations when diagnosing and treating conditions related to the appendix.

    • This question is part of the following fields:

      • Clinical Sciences
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  • Question 28 - You assess a 40-year-old woman who underwent a renal transplant 10 months ago...

    Incorrect

    • You assess a 40-year-old woman who underwent a renal transplant 10 months ago for focal segmental glomerulosclerosis. She is currently taking a combination of tacrolimus, mycophenolate, and prednisolone. She complains of feeling unwell for the past five days with fatigue, jaundice, and joint pain. Upon examination, you note hepatomegaly, widespread lymphadenopathy, and jaundice. What is the probable diagnosis?

      Your Answer:

      Correct Answer: Epstein-Barr virus

      Explanation:

      Complications that may arise after a transplant include CMV and EBV. CMV usually presents within the first 4 weeks to 6 months post transplant, while EBV can lead to post transplant lymphoproliferative disease, which typically occurs more than 6 months after the transplant. This disorder is often linked to high doses of immunosuppressant medication.

      The HLA system, also known as the major histocompatibility complex (MHC), is located on chromosome 6 and is responsible for human leucocyte antigens. Class 1 antigens include A, B, and C, while class 2 antigens include DP, DQ, and DR. When matching for a renal transplant, the importance of HLA antigens is ranked as DR > B > A.

      Graft survival rates for renal transplants are high, with a 90% survival rate at one year and a 60% survival rate at ten years for cadaveric transplants. Living-donor transplants have even higher survival rates, with a 95% survival rate at one year and a 70% survival rate at ten years. However, postoperative problems can occur, such as acute tubular necrosis of the graft, vascular thrombosis, urine leakage, and urinary tract infections.

      Hyperacute rejection can occur within minutes to hours after a transplant and is caused by pre-existing antibodies against ABO or HLA antigens. This type of rejection is an example of a type II hypersensitivity reaction and leads to widespread thrombosis of graft vessels, resulting in ischemia and necrosis of the transplanted organ. Unfortunately, there is no treatment available for hyperacute rejection, and the graft must be removed.

      Acute graft failure, which occurs within six months of a transplant, is usually due to mismatched HLA and is caused by cell-mediated cytotoxic T cells. This type of failure is usually asymptomatic and is detected by a rising creatinine, pyuria, and proteinuria. Other causes of acute graft failure include cytomegalovirus infection, but it may be reversible with steroids and immunosuppressants.

      Chronic graft failure, which occurs after six months of a transplant, is caused by both antibody and cell-mediated mechanisms that lead to fibrosis of the transplanted kidney, known as chronic allograft nephropathy. The recurrence of the original renal disease, such as MCGN, IgA, or FSGS, can also cause chronic graft failure.

    • This question is part of the following fields:

      • Renal System
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  • Question 29 - A 50-year-old male who recently completed chemotherapy for acute lymphoblastic leukemia presents with...

    Incorrect

    • A 50-year-old male who recently completed chemotherapy for acute lymphoblastic leukemia presents with exertional dyspnea, productive cough, occasional hemoptysis, and fevers.

      On a chest x-ray, an intracavitary mass with an air-crescent in the periphery is observed in the upper lobe.

      The patient is initiated on IV amphotericin.

      What is the accurate explanation of how this medication functions?

      Your Answer:

      Correct Answer: Forms a transmembrane channel that leads to monovalent ion leakage

      Explanation:

      Amphotericin B functions by binding to ergosterol, a key component of fungal cell membranes, and creating pores that lead to the destruction of the cell wall and subsequent death of the fungus. The drug’s effectiveness as a fungistatic or fungicidal agent depends on the concentration in body fluids and the susceptibility of the fungus.

      Aminoglycosides operate by binding to the 30s ribosome subunit, causing mRNA misreading. This results in the production of abnormal peptides that accumulate within the cell and ultimately lead to its demise. These antibiotics are bactericidal in nature.

      Rifampicin works by inhibiting RNA synthesis.

      Cephalosporins disrupt the synthesis of the peptidoglycan layer of bacterial cell walls by inhibiting the cross-linking of the peptidoglycan layer. This is achieved through competitive inhibition on PCB (penicillin-binding proteins).

      Trimethoprim binds to dihydrofolate reductase and prevents the reduction of dihydrofolic acid (DHF) to tetrahydrofolic acid (THF). THF is a crucial precursor in the thymidine synthesis pathway, and interference with this pathway inhibits bacterial DNA synthesis.

      Antifungal agents are drugs used to treat fungal infections. There are several types of antifungal agents, each with a unique mechanism of action and potential adverse effects. Azoles work by inhibiting 14α-demethylase, an enzyme that produces ergosterol, a component of fungal cell membranes. However, they can also inhibit the P450 system in the liver, leading to potential liver toxicity. Amphotericin B binds with ergosterol to form a transmembrane channel that causes leakage of monovalent ions, but it can also cause nephrotoxicity and flu-like symptoms. Terbinafine inhibits squalene epoxidase, while griseofulvin interacts with microtubules to disrupt mitotic spindle. However, griseofulvin can induce the P450 system and is teratogenic. Flucytosine is converted by cytosine deaminase to 5-fluorouracil, which inhibits thymidylate synthase and disrupts fungal protein synthesis, but it can cause vomiting. Caspofungin inhibits the synthesis of beta-glucan, a major fungal cell wall component, and can cause flushing. Nystatin binds with ergosterol to form a transmembrane channel that causes leakage of monovalent ions, but it is very toxic and can only be used topically, such as for oral thrush.

    • This question is part of the following fields:

      • General Principles
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  • Question 30 - A 73-year-old male slips on ice and falls, resulting in a right intertrochanteric...

    Incorrect

    • A 73-year-old male slips on ice and falls, resulting in a right intertrochanteric hip fracture. Due to his cardiac comorbidities, the anesthesiologist opts for a spinal anaesthetic over general anaesthesia. Can you list the anatomical order in which the needle passes to reach cerebrospinal fluid?

      Your Answer:

      Correct Answer: Skin -> supraspinous ligament -> interspinous ligament -> ligamentum flavum -> epidural space -> subdural space -> subarachnoid space

      Explanation:

      To reach the cerebrospinal fluid in the subarachnoid space during a mid-line approach to a spinal anaesthetic, the needle must pass through three ligaments and two meningeal layers. These include the supraspinatus ligament, interspinous ligament, ligamentum flavum, epidural space, subdural space, and subarachnoid space. Local anaesthetics, such as bupivacaine with or without opioids, are injected into the CSF to block Na+ channels and inhibit the action potential. This can reduce surgical stress and sympathetic stimulation in high-risk patients, but may also lead to vasodilation and hypotension. Spinal anaesthesia may be contraindicated in patients with coagulopathy, severe hypovolemia, increased intracranial pressure, severe aortic or mitral stenosis, or infection over the overlying skin.

      Anatomy of the Vertebral Column

      The vertebral column is composed of 33 vertebrae, which are divided into four regions: cervical, thoracic, lumbar, and sacral. The cervical region has seven vertebrae, the thoracic region has twelve, the lumbar region has five, and the sacral region has five. However, the spinal cord segmental levels do not always correspond to the vertebral segments. For example, the C8 cord is located at the C7 vertebrae, and the T12 cord is situated at the T8 vertebrae.

      The cervical vertebrae are located in the neck and are responsible for controlling the muscles of the upper extremities. The C3 cord contains the phrenic nucleus, which controls the diaphragm. The thoracic vertebrae are defined by those that have a rib and control the intercostal muscles and associated dermatomes. The lumbosacral vertebrae are located in the lower back and control the hip and leg muscles, as well as the buttocks and anal regions.

      The spinal cord ends at the L1-L2 vertebral level, and below this level is a spray of spinal roots called the cauda equina. Injuries below L2 represent injuries to spinal roots rather than the spinal cord proper. Understanding the anatomy of the vertebral column is essential for diagnosing and treating spinal cord injuries and other related conditions.

    • This question is part of the following fields:

      • Musculoskeletal System And Skin
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SESSION STATS - PERFORMANCE PER SPECIALTY

Clinical Sciences (0/2) 0%
Infectious Diseases (1/1) 100%
Cardiovascular System (0/4) 0%
Neurological System (2/3) 67%
General Principles (2/4) 50%
Renal System (0/1) 0%
Psychiatry (1/1) 100%
Gastrointestinal System (0/1) 0%
Musculoskeletal System And Skin (1/1) 100%
Endocrine System (0/1) 0%
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