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  • Question 1 - A 75-year-old diabetic man comes in with a heart attack and undergoes a...

    Incorrect

    • A 75-year-old diabetic man comes in with a heart attack and undergoes a coronary angiogram. What coronary artery/arteries provide blood supply to the anterior septum of the heart?

      Your Answer: Right coronary artery

      Correct Answer: Left Anterior Descending

      Explanation:

      The heart receives blood supply from the coronary arteries, which originate from the left side of the heart at the root of the aorta as it exits the left ventricle.

      The left coronary artery (LCA) provides blood to the left atrium and ventricle, as well as the interventricular septum. The circumflex artery, a branch of the LCA, supplies the lateral aspect of the left heart by following the coronary sulcus to the left. The left anterior descending artery (LAD), another major branch of the LCA, supplies the anteroseptal part of the heart by following the anterior interventricular sulcus around the pulmonary trunk.

      The right coronary artery (RCA) follows the coronary sulcus and supplies blood to the right atrium, portions of both ventricles, and the inferior aspect of the heart. The marginal arteries, which arise from the RCA, provide blood to the superficial portions of the right ventricle. The posterior descending artery, which branches off the RCA on the posterior surface of the heart, runs along the posterior portion of the interventricular sulcus toward the apex of the heart and supplies the interventricular septum and portions of both ventricles.

      The following table displays the relationship between ECG changes and the affected coronary artery territories. Anteroseptal changes in V1-V4 indicate involvement of the left anterior descending artery, while inferior changes in II, III, and aVF suggest the right coronary artery is affected. Anterolateral changes in V4-6, I, and aVL may indicate involvement of either the left anterior descending or left circumflex artery, while lateral changes in I, aVL, and possibly V5-6 suggest the left circumflex artery is affected. Posterior changes in V1-3 may indicate a posterior infarction, which is typically caused by the left circumflex artery but can also be caused by the right coronary artery. Reciprocal changes of STEMI are often seen as horizontal ST depression, tall R waves, upright T waves, and a dominant R wave in V2. Posterior infarction is confirmed by ST elevation and Q waves in posterior leads (V7-9), usually caused by the left circumflex artery but also possibly the right coronary artery. It is important to note that a new LBBB may indicate acute coronary syndrome.

      Diagram showing the correlation between ECG changes and coronary territories in acute coronary syndrome.

    • This question is part of the following fields:

      • Cardiovascular System
      11.7
      Seconds
  • Question 2 - A 67-year-old woman visits her GP for a routine hypertension check-up. She has...

    Incorrect

    • A 67-year-old woman visits her GP for a routine hypertension check-up. She has been on amlodipine for a year and her blood pressure is under control, but she frequently experiences ankle swelling. The swelling is more pronounced towards the end of the day since she started taking amlodipine. The GP decides to switch her medication to a diuretic. Which diuretic targets the sodium-chloride transporter in the distal tubule?

      Your Answer: Furosemide (loop diuretic)

      Correct Answer: Bendroflumethiazide (thiazide diuretic)

      Explanation:

      Thiazide diuretics are medications that work by blocking the thiazide-sensitive Na+-Cl− symporter, which inhibits sodium reabsorption at the beginning of the distal convoluted tubule (DCT). This results in the loss of potassium as more sodium reaches the collecting ducts. While thiazide diuretics are useful in treating mild heart failure, loop diuretics are more effective in reducing overload. Bendroflumethiazide was previously used to manage hypertension, but recent NICE guidelines recommend other thiazide-like diuretics such as indapamide and chlorthalidone.

      Common side effects of thiazide diuretics include dehydration, postural hypotension, and electrolyte imbalances such as hyponatremia, hypokalemia, and hypercalcemia. Other potential adverse effects include gout, impaired glucose tolerance, and impotence. Rare side effects may include thrombocytopenia, agranulocytosis, photosensitivity rash, and pancreatitis.

      It is worth noting that while thiazide diuretics may cause hypercalcemia, they can also reduce the incidence of renal stones by decreasing urinary calcium excretion. According to current NICE guidelines, the management of hypertension involves the use of thiazide-like diuretics, along with other medications and lifestyle changes, to achieve optimal blood pressure control and reduce the risk of cardiovascular disease.

    • This question is part of the following fields:

      • Cardiovascular System
      11
      Seconds
  • Question 3 - A 70-year-old male presents with abdominal pain.

    He has a past medical history...

    Incorrect

    • A 70-year-old male presents with abdominal pain.

      He has a past medical history of stroke and myocardial infarction. During examination, there was noticeable distension of the abdomen and the stools were maroon in color. The lactate level was found to be 5 mmol/L, which is above the normal range of <2.2 mmol/L.

      What is the most probable diagnosis for this patient?

      Your Answer: Ulcerative colitis

      Correct Answer: Acute mesenteric ischaemia

      Explanation:

      Acute Mesenteric Ischaemia

      Acute mesenteric ischaemia is a condition that occurs when there is a disruption in blood flow to the small intestine or right colon. This can be caused by arterial or venous disease, with arterial disease further classified as non-occlusive or occlusive. The classic triad of symptoms associated with acute mesenteric ischaemia includes gastrointestinal emptying, abdominal pain, and underlying cardiac disease.

      The hallmark symptom of mesenteric ischaemia is severe abdominal pain, which may be accompanied by other symptoms such as nausea, vomiting, abdominal distention, ileus, peritonitis, blood in the stool, and shock. Advanced ischaemia is characterized by the presence of these symptoms.

      There are several risk factors associated with acute mesenteric ischaemia, including congestive heart failure, cardiac arrhythmias (especially atrial fibrillation), recent myocardial infarction, atherosclerosis, hypercoagulable states, and hypovolaemia. It is important to be aware of these risk factors and to seek medical attention promptly if any symptoms of acute mesenteric ischaemia are present.

    • This question is part of the following fields:

      • Cardiovascular System
      10.7
      Seconds
  • Question 4 - A 67-year-old man is admitted to the hospital with central crushing chest pain...

    Incorrect

    • A 67-year-old man is admitted to the hospital with central crushing chest pain and undergoes a coronary angiogram. Arterial blockage can result from atherosclerosis, which can cause changes in the endothelium. What is an anticipated change in the endothelium?

      Your Answer: Fatty infiltration by high density lipoproteins (HDLs)

      Correct Answer: Reduced nitric oxide bioavailability

      Explanation:

      Fatty infiltration in the subendothelial space is associated with LDL particles, but the endothelium undergoes changes that include reduced nitric oxide bioavailability, proliferation, and pro-inflammatory and pro-oxidant effects.

      Understanding Atherosclerosis and its Complications

      Atherosclerosis is a complex process that occurs over several years. It begins with endothelial dysfunction triggered by factors such as smoking, hypertension, and hyperglycemia. This leads to changes in the endothelium, including inflammation, oxidation, proliferation, and reduced nitric oxide bioavailability. As a result, low-density lipoprotein (LDL) particles infiltrate the subendothelial space, and monocytes migrate from the blood and differentiate into macrophages. These macrophages that phagocytose oxidized LDL, slowly turning into large ‘foam cells’. Smooth muscle proliferation and migration from the tunica media into the intima result in the formation of a fibrous capsule covering the fatty plaque.

      Once a plaque has formed, it can cause several complications. For example, it can form a physical blockage in the lumen of the coronary artery, leading to reduced blood flow and oxygen to the myocardium, resulting in angina. Alternatively, the plaque may rupture, potentially causing a complete occlusion of the coronary artery and resulting in a myocardial infarction. It is essential to understand the process of atherosclerosis and its complications to prevent and manage cardiovascular diseases effectively.

    • This question is part of the following fields:

      • Cardiovascular System
      24.8
      Seconds
  • Question 5 - A 20-year-old man experienced recurrent episodes of breathlessness and palpitations lasting approximately 20...

    Incorrect

    • A 20-year-old man experienced recurrent episodes of breathlessness and palpitations lasting approximately 20 minutes and resolving gradually. No unusual physical signs were observed. What is the probable cause of these symptoms?

      Your Answer: Paroxysmal supraventricular tachycardia

      Correct Answer: Panic attacks

      Explanation:

      Likely Diagnosis for Sudden Onset of Symptoms

      When considering the sudden onset of symptoms, drug abuse is an unlikely cause as the symptoms are short-lived and not accompanied by other common drug abuse symptoms. Paroxysmal SVT would present with sudden starts and stops, rather than a gradual onset. Personality disorder and thyrotoxicosis would both lead to longer-lasting symptoms and other associated symptoms. Therefore, the most likely diagnosis for sudden onset symptoms would be panic disorder. It is important to consider all possible causes and seek medical attention to properly diagnose and treat any underlying conditions.

    • This question is part of the following fields:

      • Cardiovascular System
      24.7
      Seconds
  • Question 6 - A 48-year-old man visits his local doctor complaining of chest pain that occurs...

    Incorrect

    • A 48-year-old man visits his local doctor complaining of chest pain that occurs during physical activity and subsides with rest. He first noticed it 10 months ago and feels that it has gradually worsened. He now experiences this pain while climbing a few stairs. Previously, he could walk down to the newsagent and back, a distance of 200 yards, without any discomfort. He has a medical history of hypertension and appendectomy.

      His close friend had similar symptoms that were relieved by sublingual glyceryl nitrates. He asks the doctor to prescribe something similar.

      What is the mechanism by which nitrates work?

      Your Answer: Nitrates cause a decrease in extracellular calcium which results in smooth muscle relaxation

      Correct Answer: Nitrates cause a decrease in intracellular calcium which results in smooth muscle relaxation

      Explanation:

      The reason why nitrates cause a decrease in intracellular calcium is because nitric oxide triggers the activation of smooth muscle soluble guanylyl cyclase (GC) to produce cGMP. This increase in intracellular cGMP inhibits calcium entry into the cell, resulting in a reduction in intracellular calcium levels and inducing smooth muscle relaxation. Additionally, nitric oxide activates K+ channels, leading to hyperpolarization and relaxation. Furthermore, nitric oxide stimulates a cGMP-dependent protein kinase that activates myosin light chain phosphatase, which dephosphorylates myosin light chains, ultimately leading to relaxation. Therefore, the correct answer is the second option.

      Understanding Nitrates and Their Effects on the Body

      Nitrates are a type of medication that can cause blood vessels to widen, which is known as vasodilation. They are commonly used to manage angina and treat heart failure. One of the most frequently prescribed nitrates is sublingual glyceryl trinitrate, which is used to relieve angina attacks in patients with ischaemic heart disease.

      The mechanism of action for nitrates involves the release of nitric oxide in smooth muscle, which activates guanylate cyclase. This enzyme then converts GTP to cGMP, leading to a decrease in intracellular calcium levels. In the case of angina, nitrates dilate the coronary arteries and reduce venous return, which decreases left ventricular work and reduces myocardial oxygen demand.

      However, nitrates can also cause side effects such as hypotension, tachycardia, headaches, and flushing. Additionally, many patients who take nitrates develop tolerance over time, which can reduce their effectiveness. To combat this, the British National Formulary recommends that patients who develop tolerance take the second dose of isosorbide mononitrate after 8 hours instead of 12 hours. This allows blood-nitrate levels to fall for 4 hours and maintains effectiveness. It’s important to note that this effect is not seen in patients who take modified release isosorbide mononitrate.

    • This question is part of the following fields:

      • Cardiovascular System
      32.6
      Seconds
  • Question 7 - A 75-year-old man with a medical history of heart failure, ischaemic heart disease,...

    Incorrect

    • A 75-year-old man with a medical history of heart failure, ischaemic heart disease, and type 2 diabetes mellitus presents to the cardiology clinic with complaints of dyspnoea and leg swelling. Upon examination, the physician notes bibasal crackles in the lungs and bilateral pitting oedema up to the mid-shin level. The heart sounds are normal. To alleviate the symptoms, the cardiologist prescribes furosemide. Which part of the kidney does furosemide target?

      Your Answer: Na-Cl symporter in the distal convoluted tubules

      Correct Answer: Na-K-2Cl symporter in the thick ascending loop of Henle

      Explanation:

      Furosemide is a medication that is often prescribed to patients with heart failure who have excess fluid in their bodies. It works by inhibiting the Na-K-Cl cotransporter in the thick ascending limb of the loop of Henle, which prevents the reabsorption of sodium. This results in a less hypertonic renal medulla and reduces the osmotic force that causes water to be reabsorbed from the collecting ducts. As a result, more water is excreted through the kidneys.

      It is important to be aware of the common side effects of loop diuretics, which are listed in the notes below.

      Loop Diuretics: Mechanism of Action and Clinical Applications

      Loop diuretics, such as furosemide and bumetanide, are medications that inhibit the Na-K-Cl cotransporter (NKCC) in the thick ascending limb of the loop of Henle. By doing so, they reduce the absorption of NaCl, resulting in increased urine output. Loop diuretics act on NKCC2, which is more prevalent in the kidneys. These medications work on the apical membrane and must first be filtered into the tubules by the glomerulus before they can have an effect. Patients with poor renal function may require higher doses to ensure sufficient concentration in the tubules.

      Loop diuretics are commonly used in the treatment of heart failure, both acutely (usually intravenously) and chronically (usually orally). They are also indicated for resistant hypertension, particularly in patients with renal impairment. However, loop diuretics can cause adverse effects such as hypotension, hyponatremia, hypokalemia, hypomagnesemia, hypochloremic alkalosis, ototoxicity, hypocalcemia, renal impairment, hyperglycemia (less common than with thiazides), and gout. Therefore, careful monitoring of electrolyte levels and renal function is necessary when using loop diuretics.

    • This question is part of the following fields:

      • Cardiovascular System
      28
      Seconds
  • Question 8 - An 85-year-old man presents to the hospital with complaints of breathlessness at rest....

    Correct

    • An 85-year-old man presents to the hospital with complaints of breathlessness at rest. He has a medical history of type 2 diabetes and hypertension, for which he takes metformin, lisinopril, and metoprolol. He also smokes five cigarettes a day. On examination, he has a heart rate of 100 bpm, blood pressure of 128/90 mmHg, and a respiratory rate of 26 with oxygen saturation of 88% on 2l/minute. He has a regular, slow rising pulse, an ejection systolic murmur, crepitations at both lung bases, and oedema at the ankles and sacrum.

      What investigation is most crucial for his immediate management?

      Your Answer: Electrocardiogram

      Explanation:

      Managing Pulmonary Edema from Congestive Cardiac Failure

      Pulmonary edema from congestive cardiac failure requires prompt investigation and management. The most crucial investigation is an ECG to check for a possible silent myocardial infarction. Even if the ECG is normal, a troponin test may be necessary to rule out a NSTEMI. Arterial blood gas analysis is also important to guide oxygen therapy. Additionally, stopping medications such as metformin, lisinopril, and metoprolol, and administering diuretics can help manage the condition.

      It is likely that the patient has aortic stenosis, which is contributing to the cardiac failure. However, acute management of the valvular disease will be addressed separately. To learn more about heart failure and its management, refer to the ABC of heart failure articles by Millane et al. and Watson et al.

    • This question is part of the following fields:

      • Cardiovascular System
      29.2
      Seconds
  • Question 9 - A 55-year-old man arrives at the emergency department complaining of central chest pain...

    Correct

    • A 55-year-old man arrives at the emergency department complaining of central chest pain that started 15 minutes ago. An ECG is conducted and reveals ST elevation in leads I, aVL, and V6. Which coronary artery is the most probable cause of obstruction?

      Your Answer: Left circumflex artery

      Explanation:

      The presence of ischaemic changes in leads I, aVL, and V5-6 suggests a possible issue with the left circumflex artery, which supplies blood to the lateral area of the heart. Complete blockage of this artery can lead to ST elevation, while partial blockage may result in non-ST elevation myocardial infarction. Other areas of the heart and their corresponding coronary arteries are listed in the table below.

      The following table displays the relationship between ECG changes and the affected coronary artery territories. Anteroseptal changes in V1-V4 indicate involvement of the left anterior descending artery, while inferior changes in II, III, and aVF suggest the right coronary artery is affected. Anterolateral changes in V4-6, I, and aVL may indicate involvement of either the left anterior descending or left circumflex artery, while lateral changes in I, aVL, and possibly V5-6 suggest the left circumflex artery is affected. Posterior changes in V1-3 may indicate a posterior infarction, which is typically caused by the left circumflex artery but can also be caused by the right coronary artery. Reciprocal changes of STEMI are often seen as horizontal ST depression, tall R waves, upright T waves, and a dominant R wave in V2. Posterior infarction is confirmed by ST elevation and Q waves in posterior leads (V7-9), usually caused by the left circumflex artery but also possibly the right coronary artery. It is important to note that a new LBBB may indicate acute coronary syndrome.

      Diagram showing the correlation between ECG changes and coronary territories in acute coronary syndrome.

    • This question is part of the following fields:

      • Cardiovascular System
      19.6
      Seconds
  • Question 10 - A 32-year-old male is admitted for elective surgery for a lymph node biopsy...

    Correct

    • A 32-year-old male is admitted for elective surgery for a lymph node biopsy in the supraclavicular region. Following the surgery, the patient experiences difficulty in shrugging his left shoulder. What could be the probable cause?

      Your Answer: Accessory nerve lesion

      Explanation:

      The posterior triangle is where the accessory nerve is located, and it is susceptible to injury in this area. In addition to experiencing issues with shoulder shrugging, the individual may also encounter challenges when attempting to raise their arm above their head.

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

    • This question is part of the following fields:

      • Cardiovascular System
      8.1
      Seconds
  • Question 11 - A 78-year-old woman has recently been diagnosed with heart failure following 10 months...

    Incorrect

    • A 78-year-old woman has recently been diagnosed with heart failure following 10 months of progressive breathlessness and swelling in her ankles. She has been prescribed several medications and provided with lifestyle recommendations. What are the two types of infections that she is most susceptible to due to her recent diagnosis?

      Your Answer: Meningitis and infective endocarditis

      Correct Answer: Chest infections and ulcerated cellulitic legs

      Explanation:

      As a result of the volume overload caused by heart failure, she will have a higher susceptibility to chest infections due to pulmonary edema and leg infections due to peripheral edema.

      Chronic heart failure can be managed through drug treatment, according to updated guidelines issued by NICE in 2018. While loop diuretics are useful in managing fluid overload, they do not reduce mortality in the long term. The first-line treatment for all patients is a combination of an ACE-inhibitor and a beta-blocker, with clinical judgement used to determine which one to start first. Aldosterone antagonists are recommended as second-line treatment, but potassium levels should be monitored as both ACE inhibitors and aldosterone antagonists can cause hyperkalaemia. Third-line treatment should be initiated by a specialist and may include ivabradine, sacubitril-valsartan, hydralazine in combination with nitrate, digoxin, and cardiac resynchronisation therapy. Other treatments include annual influenzae and one-off pneumococcal vaccines. Those with asplenia, splenic dysfunction, or chronic kidney disease may require a booster every 5 years.

    • This question is part of the following fields:

      • Cardiovascular System
      23
      Seconds
  • Question 12 - A 56-year-old woman comes to you complaining of severe body aches and pains...

    Correct

    • A 56-year-old woman comes to you complaining of severe body aches and pains that have been ongoing for the past 2 weeks. She has been taking atorvastatin for the last 5 years and is aware of its potential side effects, but insists that she has never experienced anything like this before.

      Upon examination, her CK levels are found to be above 3000 U/L. Reviewing her medical records, it is noted that she had a medication review with her cardiologist just 2 weeks ago.

      What could be the possible cause of her current symptoms?

      Your Answer: The cardiologist started her on amiodarone

      Explanation:

      The patient’s symptoms and elevated CK levels suggest that she may have rhabdomyolysis, which is a known risk associated with taking statins while also taking amiodarone. It is likely that her cardiologist prescribed amiodarone. To reduce her risk of statin-induced rhabdomyolysis, her atorvastatin dosage should be lowered.

      It is important to note that digoxin and beta-blockers do not increase the risk of statin-induced rhabdomyolysis, and there is no association between laxatives and this condition.

      Amiodarone is a medication used to treat various types of abnormal heart rhythms. It works by blocking potassium channels, which prolongs the action potential and helps to regulate the heartbeat. However, it also has other effects, such as blocking sodium channels. Amiodarone has a very long half-life, which means that loading doses are often necessary. It should ideally be given into central veins to avoid thrombophlebitis. Amiodarone can cause proarrhythmic effects due to lengthening of the QT interval and can interact with other drugs commonly used at the same time. Long-term use of amiodarone can lead to various adverse effects, including thyroid dysfunction, corneal deposits, pulmonary fibrosis/pneumonitis, liver fibrosis/hepatitis, peripheral neuropathy, myopathy, photosensitivity, a ‘slate-grey’ appearance, thrombophlebitis, injection site reactions, and bradycardia. Patients taking amiodarone should be monitored regularly with tests such as TFT, LFT, U&E, and CXR.

    • This question is part of the following fields:

      • Cardiovascular System
      9.2
      Seconds
  • Question 13 - An 80-year-old man presents with progressive shortness of breath, easy fatigue, and ankle...

    Correct

    • An 80-year-old man presents with progressive shortness of breath, easy fatigue, and ankle swelling over the past few weeks. He has a significant smoking history of 50 pack-years. Physical examination reveals bibasilar crackles, and echocardiography shows no valvular disease and a non-dilated left ventricle with an ejection fraction of 55%. What is the most likely cause of the patient's current condition?

      Your Answer: Increased left ventricular afterload

      Explanation:

      The correct answer is increased left ventricular afterload. HFpEF, which is characterized by diastolic dysfunction, often develops due to prolonged systemic hypertension, leading to increased afterload on the left ventricle.

      Glomerular hyper-filtration is not the correct answer as heart failure leads to decreased renal perfusion pressure and glomerular hypo-filtration.

      Increased left ventricular compliance is also not the correct answer as diastolic dysfunction involves a decrease in LV compliance. LV compliance may increase with eccentric hypertrophy, which occurs in response to left ventricular volume overload.

      Left ventricular thrombus formation is not typically associated with diastolic dysfunction and HFpEF. It typically results from localized stagnation of blood, which can occur with a left ventricular aneurysm or in the setting of a severely dilated left ventricle cavity with systolic dysfunction.

      Types of Heart Failure

      Heart failure is a clinical syndrome where the heart cannot pump enough blood to meet the body’s metabolic needs. It can be classified in multiple ways, including by ejection fraction, time, and left/right side. Patients with heart failure may have a normal or abnormal left ventricular ejection fraction (LVEF), which is measured using echocardiography. Reduced LVEF is typically defined as < 35 to 40% and is termed heart failure with reduced ejection fraction (HF-rEF), while preserved LVEF is termed heart failure with preserved ejection fraction (HF-pEF). Heart failure can also be described as acute or chronic, with acute heart failure referring to an acute exacerbation of chronic heart failure. Left-sided heart failure is more common and may be due to increased left ventricular afterload or preload, while right-sided heart failure is caused by increased right ventricular afterload or preload. High-output heart failure is another type of heart failure that occurs when a normal heart is unable to pump enough blood to meet the body's metabolic needs. By classifying heart failure in these ways, healthcare professionals can better understand the underlying causes and tailor treatment plans accordingly. It is important to note that many guidelines for the management of heart failure only cover HF-rEF patients and do not address the management of HF-pEF patients. Understanding the different types of heart failure can help healthcare professionals provide more effective care for their patients.

    • This question is part of the following fields:

      • Cardiovascular System
      23.6
      Seconds
  • Question 14 - A 25-year-old man is scheduled for cardiac catheterisation to repair a possible atrial...

    Incorrect

    • A 25-year-old man is scheduled for cardiac catheterisation to repair a possible atrial septal defect. What is the typical oxygen saturation level in the right atrium for a person in good health?

      Your Answer: 90%

      Correct Answer: 70%

      Explanation:

      Understanding Oxygen Saturation Levels in Cardiac Catheterisation

      Cardiac catheterisation and oxygen saturation levels can be confusing, but with a few basic rules and logical deduction, it can be easily understood. Deoxygenated blood returns to the right side of the heart through the superior and inferior vena cava with an oxygen saturation level of around 70%. The right atrium, right ventricle, and pulmonary artery also have oxygen saturation levels of around 70%. The lungs oxygenate the blood to a level of around 98-100%, resulting in the left atrium, left ventricle, and aorta having oxygen saturation levels of 98-100%.

      Different scenarios can affect oxygen saturation levels. For instance, in an atrial septal defect (ASD), the oxygenated blood in the left atrium mixes with the deoxygenated blood in the right atrium, resulting in intermediate levels of oxygenation from the right atrium onwards. In a ventricular septal defect (VSD), the oxygenated blood in the left ventricle mixes with the deoxygenated blood in the right ventricle, resulting in intermediate levels of oxygenation from the right ventricle onwards. In a patent ductus arteriosus (PDA), the higher pressure aorta connects with the lower pressure pulmonary artery, resulting in only the pulmonary artery having intermediate oxygenation levels.

      Understanding the expected oxygen saturation levels in different scenarios can help in diagnosing and treating cardiac conditions. The table above shows the oxygen saturation levels that would be expected in different diagnoses, including VSD with Eisenmenger’s and ASD with Eisenmenger’s. By understanding these levels, healthcare professionals can provide better care for their patients.

    • This question is part of the following fields:

      • Cardiovascular System
      4.2
      Seconds
  • Question 15 - A 45-year-old woman presents to the cardiology clinic complaining of palpitations and shortness...

    Correct

    • A 45-year-old woman presents to the cardiology clinic complaining of palpitations and shortness of breath for the past 6 weeks. She has a medical history of rheumatic fever and eczema.

      During the physical examination, the patient exhibits a malar flush and a loud S1 with an opening snap is heard upon auscultation. Her heart rhythm is irregularly irregular. A chest x-ray is ordered and reveals a double heart border.

      What other symptom is this patient likely to encounter?

      Your Answer: Difficulty swallowing

      Explanation:

      The statement about left atrial enlargement compressing the esophagus in mitral stenosis is correct. This can lead to difficulty swallowing. The patient’s medical history of rheumatic fever, along with clinical signs such as malar flush, a loud S1 with opening snap, and an irregularly irregular heart rhythm (likely atrial fibrillation), suggest a diagnosis of mitral stenosis. This condition obstructs the outflow of blood from the left atrium into the left ventricle, causing the left atrium to enlarge and compress surrounding structures. Left atrial enlargement can also increase the risk of developing arrhythmias like atrial fibrillation.

      The statements about arm and facial swelling, constipation, and neck pain are incorrect. Arm and facial swelling occur due to compression of the superior vena cava, which is not caused by left atrial enlargement. Constipation is not a symptom of mitral stenosis, but patients may experience abdominal discomfort due to right-sided heart failure. Neck pain is not associated with mitral stenosis, but neck vein distention may be observed.

      Understanding Mitral Stenosis

      Mitral stenosis is a condition where the mitral valve, which controls blood flow from the left atrium to the left ventricle, becomes obstructed. This leads to an increase in pressure within the left atrium, pulmonary vasculature, and right side of the heart. The most common cause of mitral stenosis is rheumatic fever, but it can also be caused by other rare conditions such as mucopolysaccharidoses, carcinoid, and endocardial fibroelastosis.

      Symptoms of mitral stenosis include dyspnea, hemoptysis, a mid-late diastolic murmur, a loud S1, and a low volume pulse. Severe cases may also present with an increased length of murmur and a closer opening snap to S2. Chest x-rays may show left atrial enlargement, while echocardiography can confirm a cross-sectional area of less than 1 sq cm for a tight mitral stenosis.

      Management of mitral stenosis depends on the severity of the condition. Asymptomatic patients are monitored with regular echocardiograms, while symptomatic patients may undergo percutaneous mitral balloon valvotomy or mitral valve surgery. Patients with associated atrial fibrillation require anticoagulation, with warfarin currently recommended for moderate/severe cases. However, there is an emerging consensus that direct-acting anticoagulants may be suitable for mild cases with atrial fibrillation.

      Overall, understanding mitral stenosis is important for proper diagnosis and management of this condition.

    • This question is part of the following fields:

      • Cardiovascular System
      70
      Seconds
  • Question 16 - A 32-year-old arrives at the emergency department with a stab wound to the...

    Correct

    • A 32-year-old arrives at the emergency department with a stab wound to the femoral artery. He has a history of intravenous drug use.

      Due to poor vein quality, peripheral cannulation under ultrasound guidance is not feasible. Intraosseous access has been established, but additional access is required to administer large volume transfusions.

      To obtain access to a vessel that runs anterior to the medial malleolus, the consultant has decided to perform a venous cutdown.

      Which vessel will be accessed through this procedure?

      Your Answer: Long saphenous vein

      Explanation:

      The correct answer is the long saphenous vein, which passes in front of the medial malleolus and is commonly used for venous cutdown procedures. This vein is the largest vessel in the superficial venous system and is formed from the dorsal venous arch of the foot. During a venous cutdown, the skin is opened up to expose the vessel, allowing for cannulation under direct vision.

      The anterior tibial vein, fibular vein, and posterior tibial vein are all incorrect answers. The anterior tibial vein is part of the deep venous system and arises from the dorsal venous arch, while the fibular vein forms from the plantar veins of the foot and drains into the posterior tibial vein. The posterior tibial vein also arises from the plantar veins of the foot but ascends posterior to the medial malleolus.

      The Anatomy of Saphenous Veins

      The human body has two saphenous veins: the long saphenous vein and the short saphenous vein. The long saphenous vein is often used for bypass surgery or removed as a treatment for varicose veins. It originates at the first digit where the dorsal vein merges with the dorsal venous arch of the foot and runs up the medial side of the leg. At the knee, it runs over the posterior border of the medial epicondyle of the femur bone before passing laterally to lie on the anterior surface of the thigh. It then enters an opening in the fascia lata called the saphenous opening and joins with the femoral vein in the region of the femoral triangle at the saphenofemoral junction. The long saphenous vein has several tributaries, including the medial marginal, superficial epigastric, superficial iliac circumflex, and superficial external pudendal veins.

      On the other hand, the short saphenous vein originates at the fifth digit where the dorsal vein merges with the dorsal venous arch of the foot, which attaches to the great saphenous vein. It passes around the lateral aspect of the foot and runs along the posterior aspect of the leg with the sural nerve. It then passes between the heads of the gastrocnemius muscle and drains into the popliteal vein, approximately at or above the level of the knee joint.

      Understanding the anatomy of saphenous veins is crucial for medical professionals who perform surgeries or treatments involving these veins.

    • This question is part of the following fields:

      • Cardiovascular System
      3
      Seconds
  • Question 17 - A 28-year-old pregnant female arrives at the Emergency Department complaining of pleuritic chest...

    Incorrect

    • A 28-year-old pregnant female arrives at the Emergency Department complaining of pleuritic chest pain and dyspnea that came on suddenly. She recently returned from a trip to New Zealand. Based on the choices, what is the most probable finding on her ECG, if any?

      Your Answer: ST elevation in leads II, III and aVF

      Correct Answer: T wave inversion in the anterior leads

      Explanation:

      Patients with pulmonary embolism may exhibit sinus tachycardia as the most common ECG sign, as well as signs of right heart strain rather than left.

      Pulmonary embolism can be difficult to diagnose as it can present with a variety of cardiorespiratory symptoms and signs depending on its location and size. The PIOPED study in 2007 found that tachypnea, crackles, tachycardia, and fever were common clinical signs in patients diagnosed with pulmonary embolism. The Well’s criteria for diagnosing a PE use tachycardia rather than tachypnea. All patients with symptoms or signs suggestive of a PE should have a history taken, examination performed, and a chest x-ray to exclude other pathology.

      To rule out a PE, the pulmonary embolism rule-out criteria (PERC) can be used. All criteria must be absent to have a negative PERC result, which reduces the probability of PE to less than 2%. If the suspicion of PE is greater than this, a 2-level PE Wells score should be performed. A score of more than 4 points indicates a likely PE, and an immediate computed tomography pulmonary angiogram (CTPA) should be arranged. If the CTPA is negative, patients do not need further investigations or treatment for PE.

      CTPA is now the recommended initial lung-imaging modality for non-massive PE. V/Q scanning may be used initially if appropriate facilities exist, the chest x-ray is normal, and there is no significant symptomatic concurrent cardiopulmonary disease. D-dimer levels should be considered for patients over 50 years old. A chest x-ray is recommended for all patients to exclude other pathology, but it is typically normal in PE. The sensitivity of V/Q scanning is around 75%, while the specificity is 97%. Peripheral emboli affecting subsegmental arteries may be missed on CTPA.

    • This question is part of the following fields:

      • Cardiovascular System
      42.7
      Seconds
  • Question 18 - A 75-year-old man presents to the emergency department following a syncopal episode. He...

    Incorrect

    • A 75-year-old man presents to the emergency department following a syncopal episode. He has no significant medical history and denies any loss of bladder or bowel control or tongue biting.

      During examination, an ejection systolic murmur is detected at the right sternal edge in the second intercostal space. The murmur is heard radiating to the carotids.

      What intervention can be done to decrease the intensity of the murmur heard during auscultation?

      Your Answer: Raising legs

      Correct Answer: Valsalva manoeuvre

      Explanation:

      The intensity of the ejection systolic murmur heard in aortic stenosis can be decreased by performing the Valsalva manoeuvre. On the other hand, the intensity of the murmur can be increased by administering amyl nitrite, raising legs, expiration, and squatting. These actions increase the volume of blood flow through the valve.

      Aortic stenosis is a condition characterized by the narrowing of the aortic valve, which can lead to various symptoms. These symptoms include chest pain, dyspnea, syncope or presyncope, and a distinct ejection systolic murmur that radiates to the carotids. Severe aortic stenosis can cause a narrow pulse pressure, slow rising pulse, delayed ESM, soft/absent S2, S4, thrill, duration of murmur, and left ventricular hypertrophy or failure. The condition can be caused by degenerative calcification, bicuspid aortic valve, William’s syndrome, post-rheumatic disease, or subvalvular HOCM.

      Management of aortic stenosis depends on the severity of the condition and the presence of symptoms. Asymptomatic patients are usually observed, while symptomatic patients require valve replacement. Surgical AVR is the preferred treatment for young, low/medium operative risk patients, while TAVR is used for those with a high operative risk. Balloon valvuloplasty may be used in children without aortic valve calcification and in adults with critical aortic stenosis who are not fit for valve replacement. If the valvular gradient is greater than 40 mmHg and there are features such as left ventricular systolic dysfunction, surgery may be considered even if the patient is asymptomatic.

    • This question is part of the following fields:

      • Cardiovascular System
      10.8
      Seconds
  • Question 19 - A 75-year-old man presents to the emergency department with chest pain and shortness...

    Correct

    • A 75-year-old man presents to the emergency department with chest pain and shortness of breath while gardening. He reports that the pain has subsided and is able to provide a detailed medical history. He mentions feeling breathless while gardening and walking in the park, and occasionally feeling like he might faint. He has a history of hypertension, is a retired construction worker, and a non-smoker. On examination, the doctor detects a crescendo-decrescendo systolic ejection murmur. The ECG shows no ST changes and the troponin test is negative. What is the underlying pathology responsible for this man's condition?

      Your Answer: Old-age related calcification of the aortic valves

      Explanation:

      The patient’s symptoms suggest an ischemic episode of the myocardium, which could indicate an acute coronary syndrome (ACS). However, the troponin test and ECG results were negative, and there are no known risk factors for coronary artery disease. Instead, the presence of a crescendo-decrescendo systolic ejection murmur and the triad of breathlessness, chest pain, and syncope suggest a likely diagnosis of aortic stenosis, which is commonly caused by calcification of the aortic valves in older adults or abnormal valves in younger individuals.

      Arteriolosclerosis in severe systemic hypertension leads to hyperplastic proliferation of smooth muscle cells in the arterial walls, resulting in an onion-skin appearance. This is distinct from hyaline arteriolosclerosis, which is associated with diabetes mellitus and hypertension. Atherosclerosis, characterized by fibrous plaque formation in the coronary arteries, can lead to cardiac ischemia and myocyte death if the plaque ruptures and forms a thrombus.

      After a myocardial infarction, the rupture of the papillary muscle can cause mitral regurgitation, which is most likely to occur between days 2 and 7 as macrophages begin to digest necrotic myocardial tissue. The posteromedial papillary muscle is particularly at risk due to its single blood supply from the posterior descending artery.

      Aortic stenosis is a condition characterized by the narrowing of the aortic valve, which can lead to various symptoms. These symptoms include chest pain, dyspnea, syncope or presyncope, and a distinct ejection systolic murmur that radiates to the carotids. Severe aortic stenosis can cause a narrow pulse pressure, slow rising pulse, delayed ESM, soft/absent S2, S4, thrill, duration of murmur, and left ventricular hypertrophy or failure. The condition can be caused by degenerative calcification, bicuspid aortic valve, William’s syndrome, post-rheumatic disease, or subvalvular HOCM.

      Management of aortic stenosis depends on the severity of the condition and the presence of symptoms. Asymptomatic patients are usually observed, while symptomatic patients require valve replacement. Surgical AVR is the preferred treatment for young, low/medium operative risk patients, while TAVR is used for those with a high operative risk. Balloon valvuloplasty may be used in children without aortic valve calcification and in adults with critical aortic stenosis who are not fit for valve replacement. If the valvular gradient is greater than 40 mmHg and there are features such as left ventricular systolic dysfunction, surgery may be considered even if the patient is asymptomatic.

    • This question is part of the following fields:

      • Cardiovascular System
      16.6
      Seconds
  • Question 20 - A fifth-year medical student is requested to perform an abdominal examination on a...

    Incorrect

    • A fifth-year medical student is requested to perform an abdominal examination on a 58-year-old man who was admitted to the hospital with diffuse abdominal discomfort. The patient has a medical history of chronic obstructive pulmonary disease. The student noted diffuse tenderness in the abdomen without any signs of peritonism, masses, or organ enlargement. The student observed that the liver was bouncing up and down intermittently on the tips of her fingers.

      What could be the probable reason for this observation?

      Your Answer: Mitral regurgitation

      Correct Answer: Tricuspid regurgitation

      Explanation:

      Tricuspid regurgitation causes pulsatile hepatomegaly due to backflow of blood into the liver during the cardiac cycle. Other conditions such as hepatitis, mitral stenosis or mitral regurgitation do not cause this symptom.

      Tricuspid Regurgitation: Causes and Signs

      Tricuspid regurgitation is a heart condition characterized by the backflow of blood from the right ventricle to the right atrium due to the incomplete closure of the tricuspid valve. This condition can be identified through various signs, including a pansystolic murmur, prominent or giant V waves in the jugular venous pulse, pulsatile hepatomegaly, and a left parasternal heave.

      There are several causes of tricuspid regurgitation, including right ventricular infarction, pulmonary hypertension (such as in cases of COPD), rheumatic heart disease, infective endocarditis (especially in intravenous drug users), Ebstein’s anomaly, and carcinoid syndrome. It is important to identify the underlying cause of tricuspid regurgitation in order to determine the appropriate treatment plan.

    • This question is part of the following fields:

      • Cardiovascular System
      16.8
      Seconds
  • Question 21 - You are participating in a cardiology ward round with a senior consultant and...

    Incorrect

    • You are participating in a cardiology ward round with a senior consultant and encounter an 80-year-old patient. Your consultant requests that you auscultate the patient's heart and provide feedback.

      During your examination, you detect a very faint early-diastolic murmur. To identify additional indications, you palpate the patient's wrist and observe a collapsing pulse.

      What intervention could potentially amplify the intensity of the murmur?

      Your Answer: Giving the patient ACE-inhibitors

      Correct Answer: Asking patient to perform a handgrip manoeuvre

      Explanation:

      The intensity of an aortic regurgitation murmur can be increased by performing the handgrip manoeuvre, which raises afterload by contracting the arm muscles and compressing the arteries. Conversely, amyl nitrate is a vasodilator that reduces afterload by dilating peripheral arteries, while ACE inhibitors are used to treat aortic regurgitation by lowering afterload. Asking the patient to breathe in will not accentuate the murmur, but standing up or performing the Valsalva manoeuvre can decrease venous return to the heart and reduce the intensity of the murmur.

      Aortic regurgitation is a condition where the aortic valve of the heart leaks, causing blood to flow in the opposite direction during ventricular diastole. This can be caused by disease of the aortic valve or by distortion or dilation of the aortic root and ascending aorta. The most common causes of AR due to valve disease include rheumatic fever, calcific valve disease, and infective endocarditis. On the other hand, AR due to aortic root disease can be caused by conditions such as aortic dissection, hypertension, and connective tissue diseases like Marfan’s and Ehler-Danlos syndrome.

      The features of AR include an early diastolic murmur, a collapsing pulse, wide pulse pressure, Quincke’s sign, and De Musset’s sign. In severe cases, a mid-diastolic Austin-Flint murmur may also be present. Suspected AR should be investigated with echocardiography.

      Management of AR involves medical management of any associated heart failure and surgery in symptomatic patients with severe AR or asymptomatic patients with severe AR who have LV systolic dysfunction.

    • This question is part of the following fields:

      • Cardiovascular System
      16.7
      Seconds
  • Question 22 - An 80-year-old woman came in with an acute myocardial infarction. The ECG revealed...

    Correct

    • An 80-year-old woman came in with an acute myocardial infarction. The ECG revealed ST segment elevation in leads II, III, and aVF. Which coronary artery is the most probable to be blocked?

      Your Answer: Right coronary artery

      Explanation:

      Localisation of Myocardial Infarction

      Myocardial infarction (MI) is a medical emergency that occurs when there is a blockage in the blood flow to the heart muscle. The location of the blockage determines the type of MI and the treatment required. An inferior MI is caused by the occlusion of the right coronary artery, which supplies blood to the bottom of the heart. This type of MI can cause symptoms such as chest pain, shortness of breath, and nausea. It is important to identify the location of the MI quickly to provide appropriate treatment and prevent further damage to the heart muscle. Proper diagnosis and management can improve the patient’s chances of survival and reduce the risk of complications.

    • This question is part of the following fields:

      • Cardiovascular System
      21.5
      Seconds
  • Question 23 - A 45-year-old woman has varicose veins originating from the short saphenous vein. During...

    Correct

    • A 45-year-old woman has varicose veins originating from the short saphenous vein. During mobilization of the vein near its origin, which structure is at the highest risk of injury?

      Your Answer: Sural nerve

      Explanation:

      Litigation often arises from damage to the sural nerve, which is closely associated with this structure. While the other structures may also sustain injuries, the likelihood of such occurrences is comparatively lower.

      Anatomy of the Popliteal Fossa

      The popliteal fossa is a diamond-shaped space located at the back of the knee joint. It is bound by various muscles and ligaments, including the biceps femoris, semimembranosus, semitendinosus, and gastrocnemius. The floor of the popliteal fossa is formed by the popliteal surface of the femur, posterior ligament of the knee joint, and popliteus muscle, while the roof is made up of superficial and deep fascia.

      The popliteal fossa contains several important structures, including the popliteal artery and vein, small saphenous vein, common peroneal nerve, tibial nerve, posterior cutaneous nerve of the thigh, genicular branch of the obturator nerve, and lymph nodes. These structures are crucial for the proper functioning of the lower leg and foot.

      Understanding the anatomy of the popliteal fossa is important for healthcare professionals, as it can help in the diagnosis and treatment of various conditions affecting the knee joint and surrounding structures.

    • This question is part of the following fields:

      • Cardiovascular System
      6.7
      Seconds
  • Question 24 - A patient in their 60s develops complete heart block in hospital after experiencing...

    Correct

    • A patient in their 60s develops complete heart block in hospital after experiencing a myocardial infarction. Their ECG displays a heart rate of 37 beats per minute and desynchronisation of atrial and ventricular contraction. What is the most probable coronary artery that is occluded in heart block during a myocardial infarction, indicating damage to the AV node?

      Your Answer: RIght coronary artery

      Explanation:

      The atrioventricular node is most likely supplied by the right coronary artery.

      The left coronary artery gives rise to the left anterior descending and circumflex arteries.

      An anterior myocardial infarction is caused by occlusion of the left anterior descending artery.

      The coronary sinus is a venous structure that drains blood from the heart and returns it to the right atrium.

      Understanding Coronary Circulation

      Coronary circulation refers to the blood flow that supplies the heart with oxygen and nutrients. The arterial supply of the heart is divided into two main branches: the left coronary artery (LCA) and the right coronary artery (RCA). The LCA originates from the left aortic sinus, while the RCA originates from the right aortic sinus. The LCA further divides into two branches, the left anterior descending (LAD) and the circumflex artery, while the RCA supplies the posterior descending artery.

      The LCA supplies the left ventricle, left atrium, and interventricular septum, while the RCA supplies the right ventricle and the inferior wall of the left ventricle. The SA node, which is responsible for initiating the heartbeat, is supplied by the RCA in 60% of individuals, while the AV node, which is responsible for regulating the heartbeat, is supplied by the RCA in 90% of individuals.

      On the other hand, the venous drainage of the heart is through the coronary sinus, which drains into the right atrium. During diastole, the coronary arteries fill with blood, allowing for the delivery of oxygen and nutrients to the heart muscles. Understanding the coronary circulation is crucial in the diagnosis and management of various heart diseases.

    • This question is part of the following fields:

      • Cardiovascular System
      12.8
      Seconds
  • Question 25 - A 63-year-old man visits his physician complaining of exertional dyspnea. To assess his...

    Correct

    • A 63-year-old man visits his physician complaining of exertional dyspnea. To assess his heart function, he undergoes a transthoracic echocardiogram.

      What is the method used to determine his cardiac output from the echocardiogram?

      Your Answer: (end diastolic LV volume - end systolic LV volume) x heart rate

      Explanation:

      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
      13.8
      Seconds
  • Question 26 - An ECG is performed on a 60-year-old patient in the cardiology ward. On...

    Correct

    • An ECG is performed on a 60-year-old patient in the cardiology ward. On the ECG there are regular p waves present, and a QRS complex is associated with each p wave. The PR interval is 0.26 seconds. There are no missed p waves.

      What is the most probable diagnosis?

      Your Answer: 1st degree heart block

      Explanation:

      Understanding Heart Blocks: Types and Features

      Heart blocks are a type of cardiac conduction disorder that can lead to serious complications such as syncope and heart failure. There are three types of heart blocks: first degree, second degree, and third degree (complete) heart block.

      First degree heart block is characterized by a prolonged PR interval of more than 0.2 seconds. Second degree heart block can be further divided into two types: type 1 (Mobitz I, Wenckebach) and type 2 (Mobitz II). Type 1 is characterized by a progressive prolongation of the PR interval until a dropped beat occurs, while type 2 has a constant PR interval but the P wave is often not followed by a QRS complex.

      Third degree (complete) heart block is the most severe type of heart block, where there is no association between the P waves and QRS complexes. This can lead to a regular bradycardia with a heart rate of 30-50 bpm, wide pulse pressure, and cannon waves in the neck JVP. Additionally, variable intensity of S1 can be observed.

      It is important to recognize the features of heart blocks and differentiate between the types in order to provide appropriate management and prevent complications. Regular monitoring and follow-up with a healthcare provider is recommended for individuals with heart blocks.

    • This question is part of the following fields:

      • Cardiovascular System
      7.9
      Seconds
  • Question 27 - A 63-year-old male presents with right sided hemiplegia. An MRI confirms a diagnosis...

    Incorrect

    • A 63-year-old male presents with right sided hemiplegia. An MRI confirms a diagnosis of a left sided partial anterior circulating stroke. He is treated with high dose aspirin for 14 days. He is then started on clopidogrel which he was unfortunately intolerant of. You therefore start him on dual aspirin and dipyridamole.

      What is the mechanism of action of dipyridamole?

      Your Answer: Direct thrombin inhibitors

      Correct Answer: Increases the effects of adenosine

      Explanation:

      Dipyridamole is a medication that inhibits phosphodiesterase enzymes and reduces the uptake of adenosine by cells. This leads to an increase in adenosine levels and a decrease in the breakdown of cAMP. Patients taking dipyridamole should not receive exogenous adenosine treatment, such as for supraventricular tachycardia, due to this interaction.

      Clopidogrel is a medication that blocks ADP receptors.

      Aspirin is a medication that inhibits cyclo-oxygenase.

      Dabigatran and bivalirudin are medications that directly inhibit thrombin.

      Tirofiban and abciximab are medications that inhibit glycoprotein IIb/IIIa.

      Warfarin inhibits the production of factors II, VII, IX, and X.

      Understanding the Mechanism of Action of Dipyridamole

      Dipyridamole is a medication that is commonly used in combination with aspirin to prevent the formation of blood clots after a stroke or transient ischemic attack. The drug works by inhibiting phosphodiesterase, which leads to an increase in the levels of cyclic adenosine monophosphate (cAMP) in platelets. This, in turn, reduces the levels of intracellular calcium, which is necessary for platelet activation and aggregation.

      Apart from its antiplatelet effects, dipyridamole also reduces the cellular uptake of adenosine, a molecule that plays a crucial role in regulating blood flow and oxygen delivery to tissues. By inhibiting the uptake of adenosine, dipyridamole can increase its levels in the bloodstream, leading to vasodilation and improved blood flow.

      Another mechanism of action of dipyridamole is the inhibition of thromboxane synthase, an enzyme that is involved in the production of thromboxane A2, a potent platelet activator. By blocking this enzyme, dipyridamole can further reduce platelet activation and aggregation, thereby preventing the formation of blood clots.

      In summary, dipyridamole exerts its antiplatelet effects through multiple mechanisms, including the inhibition of phosphodiesterase, the reduction of intracellular calcium levels, the inhibition of thromboxane synthase, and the modulation of adenosine uptake. These actions make it a valuable medication for preventing thrombotic events in patients with a history of stroke or transient ischemic attack.

    • This question is part of the following fields:

      • Cardiovascular System
      15.6
      Seconds
  • Question 28 - A 6-year-old boy is brought to the paediatrician by his parents due to...

    Incorrect

    • A 6-year-old boy is brought to the paediatrician by his parents due to a fever and sore throat that has been bothering him for the past 24 hours. The boy is experiencing significant discomfort in his throat and has been refusing to eat or drink. He does not report having a cough or a runny nose. The boy was delivered via spontaneous vaginal delivery and has been developing normally. He has two healthy older siblings. During the examination, the doctor observes that the boy's tonsils are inflamed and enlarged, with some white exudates, as well as enlarged cervical lymph nodes. The boy's temperature is 38.2 °C. The doctor informs the parents that the boy requires antibiotics to treat the current infection and prevent the risk of a severe complication commonly associated with this particular infection. What complication can be prevented with prompt antibiotic treatment?

      Your Answer: Septicaemia

      Correct Answer: Acute rheumatic fever

      Explanation:

      Pharyngitis is the likely diagnosis for this patient based on their presenting symptoms. Group A streptococcus, also known as Streptococcus pyogenes, is a common cause of pharyngitis in young patients. One of the most concerning complications of this infection is acute rheumatic fever, which can lead to damage to the heart valves. Early antibiotic treatment can prevent the development of this serious condition.

      1: Septicemia can result from various bacterial infections, but it is not typically associated with Group A streptococcal pharyngitis. Additionally, septicemia is rare in patients with this type of pharyngitis, as the condition usually resolves on its own without treatment.

      2: Acute rheumatic fever is a serious complication of Group A streptococcal pharyngitis. It is an immune system reaction that damages the heart valves, particularly the mitral valve. Mitral valve regurgitation is common in the early stages of the disease, followed by mitral stenosis later on.

      3: Post-streptococcal glomerulonephritis is another possible complication of Group A streptococcal pharyngitis. Unlike acute rheumatic fever, however, prompt antibiotic treatment does not prevent its development.

      4: While Group A streptococcus can cause cellulitis, this is a separate condition from pharyngitis and is not a complication of the same bacterial infection.

      5:

      Rheumatic fever is a condition that occurs as a result of an immune response to a recent Streptococcus pyogenes infection, typically occurring 2-4 weeks after the initial infection. The pathogenesis of rheumatic fever involves the activation of the innate immune system, leading to antigen presentation to T cells. B and T cells then produce IgG and IgM antibodies, and CD4+ T cells are activated. This immune response is thought to be cross-reactive, mediated by molecular mimicry, where antibodies against M protein cross-react with myosin and the smooth muscle of arteries. This response leads to the clinical features of rheumatic fever, including Aschoff bodies, which are granulomatous nodules found in rheumatic heart fever.

      To diagnose rheumatic fever, evidence of recent streptococcal infection must be present, along with 2 major criteria or 1 major criterion and 2 minor criteria. Major criteria include erythema marginatum, Sydenham’s chorea, polyarthritis, carditis and valvulitis, and subcutaneous nodules. Minor criteria include raised ESR or CRP, pyrexia, arthralgia, and prolonged PR interval.

      Management of rheumatic fever involves antibiotics, typically oral penicillin V, as well as anti-inflammatories such as NSAIDs as first-line treatment. Any complications that develop, such as heart failure, should also be treated. It is important to diagnose and treat rheumatic fever promptly to prevent long-term complications such as rheumatic heart disease.

    • This question is part of the following fields:

      • Cardiovascular System
      8.2
      Seconds
  • Question 29 - A 68-year-old man is diagnosed with a transient ischaemic attack and started on...

    Incorrect

    • A 68-year-old man is diagnosed with a transient ischaemic attack and started on modified-release dipyridamole as part of combination antiplatelet treatment. He already takes a statin. After a week of treatment, he visits his GP with concerns of the drug's mechanism of action.

      What is the mechanism of action of modified-release dipyridamole?

      Your Answer: Glycoprotein IIb/IIIa inhibitor

      Correct Answer: Phosphodiesterase inhibitor

      Explanation:

      Dipyridamole is a medication that inhibits phosphodiesterase in a non-specific manner and reduces the uptake of adenosine by cells.

      As an antiplatelet agent, dipyridamole works by inhibiting phosphodiesterase. It can be used in combination with aspirin to prevent secondary transient ischemic attacks if clopidogrel is not well-tolerated.

      Tirofiban is a drug that inhibits the platelet glycoprotein IIb/IIIa receptor, which binds to collagen.

      The platelet receptor glycoprotein VI interacts with subendothelial collagen.

      Glycoprotein 1b is the platelet receptor for von Willebrand Factor. Although there is no specific drug that targets this interaction, autoantibodies to glycoprotein Ib are the basis of immune thrombocytopenic purpura (ITP).

      Clopidogrel targets the platelet receptor P2Y12, which interacts with adenosine diphosphate.

      Understanding the Mechanism of Action of Dipyridamole

      Dipyridamole is a medication that is commonly used in combination with aspirin to prevent the formation of blood clots after a stroke or transient ischemic attack. The drug works by inhibiting phosphodiesterase, which leads to an increase in the levels of cyclic adenosine monophosphate (cAMP) in platelets. This, in turn, reduces the levels of intracellular calcium, which is necessary for platelet activation and aggregation.

      Apart from its antiplatelet effects, dipyridamole also reduces the cellular uptake of adenosine, a molecule that plays a crucial role in regulating blood flow and oxygen delivery to tissues. By inhibiting the uptake of adenosine, dipyridamole can increase its levels in the bloodstream, leading to vasodilation and improved blood flow.

      Another mechanism of action of dipyridamole is the inhibition of thromboxane synthase, an enzyme that is involved in the production of thromboxane A2, a potent platelet activator. By blocking this enzyme, dipyridamole can further reduce platelet activation and aggregation, thereby preventing the formation of blood clots.

      In summary, dipyridamole exerts its antiplatelet effects through multiple mechanisms, including the inhibition of phosphodiesterase, the reduction of intracellular calcium levels, the inhibition of thromboxane synthase, and the modulation of adenosine uptake. These actions make it a valuable medication for preventing thrombotic events in patients with a history of stroke or transient ischemic attack.

    • This question is part of the following fields:

      • Cardiovascular System
      8.3
      Seconds
  • Question 30 - A 68-year-old woman has a left ankle ulcer that has been present for...

    Incorrect

    • A 68-year-old woman has a left ankle ulcer that has been present for nine months. She had a DVT in her right leg five years ago. Upon examination, there is a 6 cm diameter slough-based ulcer on the medial malleolus without cellulitis. What investigation is required before applying compression bandaging?

      Your Answer: Venous duplex ultrasound scan

      Correct Answer: Ankle-brachial pressure index

      Explanation:

      Venous Ulceration and the Importance of Identifying Arterial Disease

      Venous ulcerations are a common type of ulcer that affects the lower extremities. The underlying cause of venous congestion, which can promote ulceration, is venous insufficiency. The treatment for venous ulceration involves controlling oedema, treating any infection, and compression. However, compressive dressings or devices should not be applied if the arterial circulation is impaired. Therefore, it is crucial to identify any arterial disease, and the ankle-brachial pressure index is a simple way of doing this. If indicated, one may progress to a lower limb arteriogram.

      It is important to note that there is no clinical sign of infection, and although a bacterial swab would help to rule out pathogens within the ulcer, arterial insufficiency is the more important issue. If there is a clinical suspicion of DVT, then duplex (or rarely a venogram) is indicated to decide on the indication for anticoagulation. By identifying arterial disease, healthcare professionals can ensure that appropriate treatment is provided and avoid potential complications from compressive dressings or devices.

    • This question is part of the following fields:

      • Cardiovascular System
      7
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Cardiovascular System (13/30) 43%
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