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Question 1
Incorrect
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Which vessel is the first to branch from the external carotid artery?
Your Answer: Occipital artery
Correct Answer: Superior thyroid artery
Explanation:Here is a mnemonic to remember the order in which the branches of the external carotid artery originate: Some Attendings Like Freaking Out Potential Medical Students. The first branch is the superior thyroid artery, followed by the ascending pharyngeal, lingual, facial, occipital, post auricular, and finally the maxillary and superficial temporal arteries.
Anatomy of the External Carotid Artery
The external carotid artery begins on the side of the pharynx and runs in front of the internal carotid artery, behind the posterior belly of digastric and stylohyoid muscles. It is covered by sternocleidomastoid muscle and passed by hypoglossal nerves, lingual and facial veins. The artery then enters the parotid gland and divides into its terminal branches within the gland.
To locate the external carotid artery, an imaginary line can be drawn from the bifurcation of the common carotid artery behind the angle of the jaw to a point in front of the tragus of the ear.
The external carotid artery has six branches, with three in front, two behind, and one deep. The three branches in front are the superior thyroid, lingual, and facial arteries. The two branches behind are the occipital and posterior auricular arteries. The deep branch is the ascending pharyngeal artery. The external carotid artery terminates by dividing into the superficial temporal and maxillary arteries within the parotid gland.
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This question is part of the following fields:
- Cardiovascular System
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Question 2
Correct
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A 45-year-old male with no past medical history is recently diagnosed with hypertension. His GP prescribes him lisinopril and orders a baseline renal function blood test, which comes back normal. The GP schedules a follow-up appointment for two weeks later to check his renal function. At the follow-up appointment, the patient's blood test results show:
Na 137 mmol/l
K 4.7 mmol/l
Cl 98 mmol/l
Urea 12.2 mmol/l
Creatinine 250 mg/l
What is the most likely cause for the abnormal blood test results?Your Answer: Bilateral stenosis of renal arteries
Explanation:Patients with renovascular disease should not be prescribed ACE inhibitors as their first line antihypertensive medication. This is because bilateral renal artery stenosis, a common cause of hypertension, can go undetected and lead to acute renal impairment when treated with ACE inhibitors. This occurs because the medication prevents the constriction of efferent arterioles, which is necessary to maintain glomerular pressure in patients with reduced blood flow to the kidneys. Therefore, further investigations such as a renal artery ultrasound scan should be conducted before prescribing ACE inhibitors to patients with hypertension.
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.
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This question is part of the following fields:
- Cardiovascular System
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Question 3
Incorrect
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A 50-year-old man comes to the clinic complaining of gynaecomastia. He is currently undergoing treatment for heart failure and gastro-oesophageal reflux. Which medication that he is taking is the most probable cause of his gynaecomastia?
Your Answer:
Correct Answer: Spironolactone
Explanation:Medications Associated with Gynaecomastia
Gynaecomastia, the enlargement of male breast tissue, can be caused by various medications. Spironolactone, ciclosporin, cimetidine, and omeprazole are some of the drugs that have been associated with this condition. Ramipril has also been linked to gynaecomastia, but it is a rare occurrence.
Aside from these medications, other drugs that can cause gynaecomastia include digoxin, LHRH analogues, cimetidine, and finasteride. It is important to note that not all individuals who take these medications will develop gynaecomastia, and the risk may vary depending on the dosage and duration of treatment.
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This question is part of the following fields:
- Cardiovascular System
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Question 4
Incorrect
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You are a doctor working in the intensive care unit. A 35-year-old man has been admitted to the ward due to suddenly vomiting large volumes of fresh blood. His blood pressure is 90/60 mmHg and his heart rate is 150bpm. He needs urgent intravenous fluids. Several attempts at intravenous cannulation have been made but to no avail. The on-call anaesthetist suggests performing a great saphenous vein cutdown.
Where should the anaesthetist make the incision?Your Answer:
Correct Answer: Anterior to the medial malleolus
Explanation:The long saphenous vein is often used for venous cutdown and passes in front of the medial malleolus. Venous cutdown involves surgically exposing a vein for cannulation.
On the other hand, the short saphenous vein is situated in front of the lateral malleolus and runs up the back of the thigh to drain into the popliteal vein at the popliteal fossa.
The long saphenous vein originates from the point where the first dorsal digital vein, which drains the big toe, joins the dorsal venous arch of the foot. It then passes in front of the medial malleolus, ascends the medial aspect of the thigh, and drains into the femoral vein by passing through the saphenous opening.
The femoral vein becomes the external iliac vein at the inferior margin of the inguinal ligament. It receives blood from the great saphenous and popliteal veins, and a deep vein thrombosis that blocks this vein can be life-threatening.
During a vascular examination of the lower limb, the dorsalis pedis artery is often palpated. It runs alongside the extensor digitorum longus.
Lastly, the posterior tibial vein is located at the back of the medial malleolus, together with other structures, within the tarsal tunnel.
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.
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This question is part of the following fields:
- Cardiovascular System
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Question 5
Incorrect
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A 56-year-old man visits his GP complaining of congestive heart failure, angina, and exertional syncope. During the examination, the doctor observes a forceful apex beat and a systolic ejection murmur at the upper right sternal border.
What condition is most likely causing these symptoms?Your Answer:
Correct Answer: Aortic stenosis
Explanation:Symptoms and Diagnosis of Heart Valve Disorders
Heart valve disorders can cause a range of symptoms depending on the type and severity of the condition. Aortic stenosis, for example, can lead to obstruction of left ventricular emptying, resulting in slow rising carotid pulse and a palpated murmur that may radiate to the neck. Aortic valve replacement is necessary for symptomatic patients to prevent death within three years or those with severe valve narrowing on ECHO. On the other hand, aortic regurgitation may not show any symptoms for many years until dyspnoea and fatigue set in. A blowing early diastolic murmur is typically found at the left sternal edge, and a mid-diastolic murmur may also be present over the apex of the heart.
Mitral regurgitation, whether acute or chronic, can cause pulmonary oedema, exertional dyspnoea, and lethargy. A pansystolic murmur is audible at the apex. Mitral stenosis, meanwhile, initially presents with exertional dyspnoea, but haemoptysis and a productive cough may also occur. A rumbling mid-diastolic murmur is indicative of mitral stenosis. Finally, a prolapsing mitral valve is common in young women and is usually asymptomatic, although atypical chest pain may be present. Overall, proper diagnosis and treatment of heart valve disorders are crucial to prevent complications and improve quality of life.
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This question is part of the following fields:
- Cardiovascular System
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Question 6
Incorrect
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A 46-year-old man with a history of hypertrophic cardiomyopathy (HOCM) presents for evaluation at the cardiology clinic. During the assessment, a fourth heart sound is detected.
What characteristic is associated with this clinical observation?Your Answer:
Correct Answer: It coincides with the P wave of the ECG
Explanation:The S4 heart sound occurs simultaneously with the P wave on an ECG. This sound is heard during late diastole when the left ventricle is being actively filled and the atrial contraction is forcing blood into a noncompliant left ventricle. The P wave on the ECG represents the depolarization of the left and right atrium, which results in atrial contraction. Therefore, the S4 heart sound coincides with the P wave on the ECG.
The presence of an S4 heart sound can indicate diastolic heart failure, which is caused by severe left ventricular hypertrophy. This condition can be found in patients with HOCM or can develop as a complication of hypertension or aortic stenosis.
In contrast, the S3 heart sound occurs during early diastole when the left ventricle is being passively filled.
During diastole, the T wave on the ECG represents the repolarization of the ventricles and marks the beginning of ventricular relaxation.
Heart sounds are the sounds produced by the heart during its normal functioning. The first heart sound (S1) is caused by the closure of the mitral and tricuspid valves, while the second heart sound (S2) is due to the closure of the aortic and pulmonary valves. The intensity of these sounds can vary depending on the condition of the valves and the heart. The third heart sound (S3) is caused by the diastolic filling of the ventricle and is considered normal in young individuals. However, it may indicate left ventricular failure, constrictive pericarditis, or mitral regurgitation in older individuals. The fourth heart sound (S4) may be heard in conditions such as aortic stenosis, HOCM, and hypertension, and is caused by atrial contraction against a stiff ventricle. The different valves can be best heard at specific sites on the chest wall, such as the left second intercostal space for the pulmonary valve and the right second intercostal space for the aortic valve.
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This question is part of the following fields:
- Cardiovascular System
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Question 7
Incorrect
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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:
Correct 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.
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This question is part of the following fields:
- Cardiovascular System
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Question 8
Incorrect
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Isabella is an 82-year-old female who visits the cardiology clinic for a check-up. She experienced a heart attack half a year ago and has been experiencing swollen ankles and difficulty breathing when lying down. You suspect heart failure and arrange for an echocardiogram, prescribe diuretic medications, and conduct a blood test. What blood marker can indicate excessive stretching of the heart muscle?
Your Answer:
Correct Answer: Brain natriuretic peptide (BNP)
Explanation:BNP is produced by the ventricles of the heart when the cardiomyocytes are excessively stretched. Its overall effect is to reduce blood pressure by decreasing systemic vascular resistance and increasing natriuresis.
Troponin is a protein that plays a role in cardiac muscle contraction and is a specific and sensitive marker for myocardial damage in cases of myocardial infarction.
Creatine kinase and LDH can be used as acute markers for myocardial infarction.
Myoglobin is released after muscle damage, but it is not specific to acute myocardial infarction and is typically measured in cases of rhabdomyolysis.
B-type natriuretic peptide (BNP) is a hormone that is primarily produced by the left ventricular myocardium in response to strain. Although heart failure is the most common cause of elevated BNP levels, any condition that causes left ventricular dysfunction, such as myocardial ischemia or valvular disease, may also raise levels. In patients with chronic kidney disease, reduced excretion may also lead to elevated BNP levels. Conversely, treatment with ACE inhibitors, angiotensin-2 receptor blockers, and diuretics can lower BNP levels.
BNP has several effects, including vasodilation, diuresis, natriuresis, and suppression of both sympathetic tone and the renin-angiotensin-aldosterone system. Clinically, BNP is useful in diagnosing patients with acute dyspnea. A low concentration of BNP (<100 pg/mL) makes a diagnosis of heart failure unlikely, but elevated levels should prompt further investigation to confirm the diagnosis. Currently, NICE recommends BNP as a helpful test to rule out a diagnosis of heart failure. In patients with chronic heart failure, initial evidence suggests that BNP is an extremely useful marker of prognosis and can guide treatment. However, BNP is not currently recommended for population screening for cardiac dysfunction.
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This question is part of the following fields:
- Cardiovascular System
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Question 9
Incorrect
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A 70-year-old male arrives at the emergency department complaining of tearing chest pain that radiates to his back. He has a history of uncontrolled hypertension. During auscultation, a diastolic murmur is heard, which is most audible over the 2nd intercostal space, right sternal border. What chest radiograph findings are expected from this patient's presentation?
Your Answer:
Correct Answer: Widened mediastinum
Explanation:Aortic dissection can cause a widened mediastinum on a chest x-ray. This condition is characterized by tearing chest pain that radiates to the back, hypertension, and aortic regurgitation. It occurs when there is a tear in the tunica intima of the aorta’s wall, creating a false lumen that fills with a large volume of blood.
Calcification of the arch of the aorta, cardiomegaly, displacement of the trachea from the midline, and enlargement of the aortic knob are not commonly associated with aortic dissection. Calcification of the walls of arteries is a chronic process that occurs with age and is more likely in men. Cardiomegaly can be caused by various conditions, including ischaemic heart disease and congenital abnormalities. Displacement of the trachea from the midline can result from other pathologies such as a tension pneumothorax or an aortic aneurysm. Enlargement of the aortic knob is a classical finding of an aortic aneurysm.
Aortic dissection is classified according to the location of the tear in the aorta. The Stanford classification divides it into type A, which affects the ascending aorta in two-thirds of cases, and type B, which affects the descending aorta distal to the left subclavian origin in one-third of cases. The DeBakey classification divides it into type I, which originates in the ascending aorta and propagates to at least the aortic arch and possibly beyond it distally, type II, which originates in and is confined to the ascending aorta, and type III, which originates in the descending aorta and rarely extends proximally but will extend distally.
To diagnose aortic dissection, a chest x-ray may show a widened mediastinum, but CT angiography of the chest, abdomen, and pelvis is the investigation of choice. However, the choice of investigations should take into account the patient’s clinical stability, as they may present acutely and be unstable. Transoesophageal echocardiography (TOE) is more suitable for unstable patients who are too risky to take to the CT scanner.
The management of type A aortic dissection is surgical, but blood pressure should be controlled to a target systolic of 100-120 mmHg while awaiting intervention. On the other hand, type B aortic dissection is managed conservatively with bed rest and IV labetalol to reduce blood pressure and prevent progression. Complications of a backward tear include aortic incompetence/regurgitation and MI, while complications of a forward tear include unequal arm pulses and BP, stroke, and renal failure. Endovascular repair of type B aortic dissection may have a role in the future.
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This question is part of the following fields:
- Cardiovascular System
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Question 10
Incorrect
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A 36-year-old woman presents to her GP with a history of long-standing fatigue, dyspnea, and chest discomfort that has recently worsened. Despite being physically active, she has been experiencing these symptoms. She is a social drinker and does not smoke. Her family history is unremarkable except for her mother who died of 'chest disease' at the age of 50. During examination, her observations are as follows:
Blood pressure: 135/85mmHg
Pulse: 95 beats/min
Respiration: 25 breaths/min
An ECG shows no abnormalities, and cardiac enzymes are within normal ranges. She is referred for echocardiography, which reveals a right pulmonary artery pressure of 35 mmhg.
What substance is elevated in this patient, underlying the disease process?Your Answer:
Correct Answer: Endothelin
Explanation:Understanding Endothelin and Its Role in Various Diseases
Endothelin is a potent vasoconstrictor and bronchoconstrictor that is secreted by the vascular endothelium. Initially, it is produced as a prohormone and later converted to ET-1 by the action of endothelin converting enzyme. Endothelin interacts with a G-protein linked to phospholipase C, leading to calcium release. This interaction is thought to be important in the pathogenesis of many diseases, including primary pulmonary hypertension, cardiac failure, hepatorenal syndrome, and Raynaud’s.
Endothelin is known to promote the release of angiotensin II, ADH, hypoxia, and mechanical shearing forces. On the other hand, it inhibits the release of nitric oxide and prostacyclin. Raised levels of endothelin are observed in primary pulmonary hypertension, myocardial infarction, heart failure, acute kidney injury, and asthma.
In recent years, endothelin antagonists have been used to treat primary pulmonary hypertension. Understanding the role of endothelin in various diseases can help in the development of new treatments and therapies.
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This question is part of the following fields:
- Cardiovascular System
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Question 11
Incorrect
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A 50-year-old man undergoes carotid endarterectomy surgery after experiencing a transient ischaemic attack. The procedure is successful with no complications. However, the patient develops new hoarseness of voice and loss of effective cough mechanism post-surgery. There are no notable findings upon examination of the oral cavity.
Which structure has been affected by the surgery?Your Answer:
Correct Answer: Cranial nerve X
Explanation:Speech is innervated by the vagus (X) nerve, so any damage to this nerve can cause speech problems. Injuries to one side of the vagus nerve can result in hoarseness and vocal cord paralysis on the same side, while bilateral injuries can lead to aphonia and stridor. Other symptoms of vagal disease may include dysphagia, loss of cough reflex, gastroparesis, and cardiovascular effects. The facial nerve (VII) may also be affected during carotid surgery, causing muscle weakness in facial expression. However, the vestibulocochlear nerve (VIII) is not involved in speech and would not be damaged during carotid surgery. The accessory nerve (XI) does not innervate speech muscles and is rarely affected during carotid surgery, causing weakness in shoulder elevation instead. Hypoglossal (XII) palsy is a rare complication of carotid surgery that causes tongue deviation towards the side of the lesion, but not voice hoarseness.
The vagus nerve is responsible for a variety of functions and supplies structures from the fourth and sixth pharyngeal arches, as well as the fore and midgut sections of the embryonic gut tube. It carries afferent fibers from areas such as the pharynx, larynx, esophagus, stomach, lungs, heart, and great vessels. The efferent fibers of the vagus are of two main types: preganglionic parasympathetic fibers distributed to the parasympathetic ganglia that innervate smooth muscle of the innervated organs, and efferent fibers with direct skeletal muscle innervation, largely to the muscles of the larynx and pharynx.
The vagus nerve arises from the lateral surface of the medulla oblongata and exits through the jugular foramen, closely related to the glossopharyngeal nerve cranially and the accessory nerve caudally. It descends vertically in the carotid sheath in the neck, closely related to the internal and common carotid arteries. In the mediastinum, both nerves pass posteroinferiorly and reach the posterior surface of the corresponding lung root, branching into both lungs. At the inferior end of the mediastinum, these plexuses reunite to form the formal vagal trunks that pass through the esophageal hiatus and into the abdomen. The anterior and posterior vagal trunks are formal nerve fibers that splay out once again, sending fibers over the stomach and posteriorly to the coeliac plexus. Branches pass to the liver, spleen, and kidney.
The vagus nerve has various branches in the neck, including superior and inferior cervical cardiac branches, and the right recurrent laryngeal nerve, which arises from the vagus anterior to the first part of the subclavian artery and hooks under it to insert into the larynx. In the thorax, the left recurrent laryngeal nerve arises from the vagus on the aortic arch and hooks around the inferior surface of the arch, passing upwards through the superior mediastinum and lower part of the neck. In the abdomen, the nerves branch extensively, passing to the coeliac axis and alongside the vessels to supply the spleen, liver, and kidney.
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This question is part of the following fields:
- Cardiovascular System
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Question 12
Incorrect
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A person in their 60s is prescribed clopidogrel following a transient ischaemic attack. What is the mechanism of action of clopidogrel as an antiplatelet medication?
Clopidogrel is prescribed to prevent blood clots from forming by inhibiting platelet aggregation. It works by irreversibly binding to the P2Y12 receptor on the platelet surface, which prevents the activation of the glycoprotein IIb/IIIa complex. This complex is responsible for the final common pathway of platelet aggregation, so by inhibiting its activation, clopidogrel reduces the risk of thrombotic events such as stroke or myocardial infarction.Your Answer:
Correct Answer: ADP receptor antagonist
Explanation:Clopidogrel works by blocking ADP receptors, which prevents platelet activation and the formation of blood clots.
Aspirin and other NSAIDs inhibit the COX-1 enzyme, leading to a decrease in prostaglandins and thromboxane, which helps to prevent blood clots.
Antiplatelet medications like abciximab and eptifibatide work by blocking glycoprotein IIb/IIIa receptors on platelets, which prevents platelet adhesion and activation.
Increasing thrombomodulin expression and prostacyclin levels would have the opposite effect and increase blood coagulability and platelet production.
Clopidogrel: An Antiplatelet Agent for Cardiovascular Disease
Clopidogrel is a medication used to manage cardiovascular disease by preventing platelets from sticking together and forming clots. It is commonly used in patients with acute coronary syndrome and is now also recommended as a first-line treatment for patients following an ischaemic stroke or with peripheral arterial disease. Clopidogrel belongs to a class of drugs called thienopyridines, which work in a similar way. Other examples of thienopyridines include prasugrel, ticagrelor, and ticlopidine.
Clopidogrel works by blocking the P2Y12 adenosine diphosphate (ADP) receptor, which prevents platelets from becoming activated. However, concurrent use of proton pump inhibitors (PPIs) may make clopidogrel less effective. The Medicines and Healthcare products Regulatory Agency (MHRA) issued a warning in July 2009 about this interaction, and although evidence is inconsistent, omeprazole and esomeprazole are still cause for concern. Other PPIs, such as lansoprazole, are generally considered safe to use with clopidogrel. It is important to consult with a healthcare provider before taking any new medications or supplements.
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This question is part of the following fields:
- Cardiovascular System
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Question 13
Incorrect
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A 26-year-old man collapses during a game of cricket. He has previously experienced chest pain and shortness of breath while running, which subsides on rest. Upon examination, he is found to have an ejection systolic murmur that intensifies with Valsalva maneuvers and diminishes with squatting. His echocardiogram reveals mitral regurgitation, asymmetric hypertrophy, and systolic anterior motion of the anterior mitral valve leaflet. What is the expected inheritance pattern for this diagnosis?
Your Answer:
Correct Answer: Autosomal dominant
Explanation:The inheritance pattern of HOCM is autosomal dominant, which means that it can be passed down from generation to generation. Symptoms of HOCM may include exertional dyspnoea, angina, syncope, and an ejection systolic murmur. It is important to note that there may be a family history of similar cardiac problems or sudden death due to ventricular arrhythmias. Autosomal recessive, mitochondrial inheritance, and X-linked dominant inheritance are not applicable to HOCM.
Hypertrophic obstructive cardiomyopathy (HOCM) is a genetic disorder that affects muscle tissue and is inherited in an autosomal dominant manner. It is caused by mutations in genes that encode contractile proteins, with the most common defects involving the β-myosin heavy chain protein or myosin-binding protein C. HOCM is characterized by left ventricle hypertrophy, which leads to decreased compliance and cardiac output, resulting in predominantly diastolic dysfunction. Biopsy findings show myofibrillar hypertrophy with disorganized myocytes and fibrosis. HOCM is often asymptomatic, but exertional dyspnea, angina, syncope, and sudden death can occur. Jerky pulse, systolic murmurs, and double apex beat are also common features. HOCM is associated with Friedreich’s ataxia and Wolff-Parkinson White. ECG findings include left ventricular hypertrophy, non-specific ST segment and T-wave abnormalities, and deep Q waves. Atrial fibrillation may occasionally be seen.
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This question is part of the following fields:
- Cardiovascular System
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Question 14
Incorrect
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A 28-year-old pregnant woman discusses her varicose veins with her midwife. She has noticed these veins for a couple of weeks now, and they appeared during her pregnancy. Lately, she has observed red-brown discoloration around the veins on the back of her calf. What could be the probable root cause of this?
Your Answer:
Correct Answer: Haemosiderin deposition
Explanation:The hyperpigmentation observed in patients with varicose eczema/venous ulcers is likely caused by haemosiderin deposition. This occurs when red blood cells burst due to venous stasis, leading to the release of haemoglobin which is stored as haemosiderin. The excess haemosiderin causes a local red-brown discolouration around areas of varicose veins.
Acanthosis nigricans is an unlikely cause as it is associated with metabolic disorders and not varicose veins. Atrophie blanche describes hypopigmentation seen in venous ulcers, while lipodermatosclerosis causes thickening of the skin in varicose veins without changing the skin color. Melanoma, a skin cancer that causes dark discolouration, is unlikely to be associated with varicose veins and is an unlikely explanation for the observed discolouration on the back of the calf.
Understanding Varicose Veins
Varicose veins are enlarged and twisted veins that occur when the valves in the veins become weak or damaged, causing blood to flow backward and pool in the veins. They are most commonly found in the legs and can be caused by various factors such as age, gender, pregnancy, obesity, and genetics. While many people seek treatment for cosmetic reasons, others may experience symptoms such as aching, throbbing, and itching. In severe cases, varicose veins can lead to skin changes, bleeding, superficial thrombophlebitis, and venous ulceration.
To diagnose varicose veins, a venous duplex ultrasound is typically performed to detect retrograde venous flow. Treatment options vary depending on the severity of the condition. Conservative treatments such as leg elevation, weight loss, regular exercise, and compression stockings may be recommended for mild cases. However, patients with significant or troublesome symptoms, skin changes, or a history of bleeding or ulcers may require referral to a specialist for further evaluation and treatment. Possible treatments include endothermal ablation, foam sclerotherapy, or surgery.
In summary, varicose veins are a common condition that can cause discomfort and cosmetic concerns. While many cases do not require intervention, it is important to seek medical attention if symptoms or complications arise. With proper diagnosis and treatment, patients can manage their condition and improve their quality of life.
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This question is part of the following fields:
- Cardiovascular System
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Question 15
Incorrect
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A 45-year-old woman presents to the emergency department with a severe headache that started suddenly during exercise. She reports vomiting and recurrent vertigo sensations. On examination, she has an ataxic gait, left-sided horizontal nystagmus, and an intention tremor during the 'finger-to-nose' test. An urgent CT scan is ordered. Which arteries provide blood supply to the affected area of the brain?
Your Answer:
Correct Answer: Basilar and the vertebral arteries
Explanation:The correct answer is the basilar and vertebral arteries, which form branches that supply the cerebellum. The patient’s sudden onset headache, vomiting, and vertigo suggest a pathology focused on the brain, with ataxia, nystagmus, and intention tremor indicating cerebellar syndrome. A CT scan is necessary to rule out a cerebellar haemorrhage or stroke, as the basilar and vertebral arteries are the main arterial supply to the cerebellum.
The incorrect answer is the anterior and middle cerebral arteries, which supply the cerebral cortex and would present with different symptoms. The anterior and posterior spinal arteries are also incorrect, as they supply the spine and would present with different symptoms. The ophthalmic and central retinal artery is also incorrect, as it would only present with visual symptoms and not the other symptoms seen in this patient.
The Circle of Willis is an anastomosis formed by the internal carotid arteries and vertebral arteries on the bottom surface of the brain. It is divided into two halves and is made up of various arteries, including the anterior communicating artery, anterior cerebral artery, internal carotid artery, posterior communicating artery, and posterior cerebral arteries. The circle and its branches supply blood to important areas of the brain, such as the corpus striatum, internal capsule, diencephalon, and midbrain.
The vertebral arteries enter the cranial cavity through the foramen magnum and lie in the subarachnoid space. They then ascend on the anterior surface of the medulla oblongata and unite to form the basilar artery at the base of the pons. The basilar artery has several branches, including the anterior inferior cerebellar artery, labyrinthine artery, pontine arteries, superior cerebellar artery, and posterior cerebral artery.
The internal carotid arteries also have several branches, such as the posterior communicating artery, anterior cerebral artery, middle cerebral artery, and anterior choroid artery. These arteries supply blood to different parts of the brain, including the frontal, temporal, and parietal lobes. Overall, the Circle of Willis and its branches play a crucial role in providing oxygen and nutrients to the brain.
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This question is part of the following fields:
- Cardiovascular System
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Question 16
Incorrect
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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:
Correct 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.
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This question is part of the following fields:
- Cardiovascular System
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Question 17
Incorrect
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During surgery on her neck, a woman in her 50s suffers a vagus nerve injury where the nerve is cut near the exit from the skull. She wakes up with a high heart rate and high blood pressure due to loss of parasympathetic tone.
What other features would be expected with a vagus nerve injury?Your Answer:
Correct Answer: Hoarse voice
Explanation:The vagus (X) nerve is responsible for all innervation related to speech, meaning that any injuries to this nerve can lead to speech problems. It’s important to note that the vagus nerve has both autonomic and somatic effects, with the latter being the most crucial for speech. This involves the motor supply to the larynx through the recurrent laryngeal nerves, which are branches of the vagus. If one vagus nerve is damaged, it would have the same impact as damage to a single recurrent laryngeal nerve, resulting in a hoarse voice.
However, it’s worth noting that anal tone, erections, and urination are controlled by the sacral parasympathetics and would not be affected by the loss of the vagus nerve. Similarly, pupillary constriction is controlled by parasympathetics on the oculomotor nerve and would not be impacted by the loss of the vagus nerve.
The vagus nerve is responsible for a variety of functions and supplies structures from the fourth and sixth pharyngeal arches, as well as the fore and midgut sections of the embryonic gut tube. It carries afferent fibers from areas such as the pharynx, larynx, esophagus, stomach, lungs, heart, and great vessels. The efferent fibers of the vagus are of two main types: preganglionic parasympathetic fibers distributed to the parasympathetic ganglia that innervate smooth muscle of the innervated organs, and efferent fibers with direct skeletal muscle innervation, largely to the muscles of the larynx and pharynx.
The vagus nerve arises from the lateral surface of the medulla oblongata and exits through the jugular foramen, closely related to the glossopharyngeal nerve cranially and the accessory nerve caudally. It descends vertically in the carotid sheath in the neck, closely related to the internal and common carotid arteries. In the mediastinum, both nerves pass posteroinferiorly and reach the posterior surface of the corresponding lung root, branching into both lungs. At the inferior end of the mediastinum, these plexuses reunite to form the formal vagal trunks that pass through the esophageal hiatus and into the abdomen. The anterior and posterior vagal trunks are formal nerve fibers that splay out once again, sending fibers over the stomach and posteriorly to the coeliac plexus. Branches pass to the liver, spleen, and kidney.
The vagus nerve has various branches in the neck, including superior and inferior cervical cardiac branches, and the right recurrent laryngeal nerve, which arises from the vagus anterior to the first part of the subclavian artery and hooks under it to insert into the larynx. In the thorax, the left recurrent laryngeal nerve arises from the vagus on the aortic arch and hooks around the inferior surface of the arch, passing upwards through the superior mediastinum and lower part of the neck. In the abdomen, the nerves branch extensively, passing to the coeliac axis and alongside the vessels to supply the spleen, liver, and kidney.
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This question is part of the following fields:
- Cardiovascular System
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Question 18
Incorrect
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A 63-year-old man comes to the emergency department complaining of severe crushing chest pain that radiates to his jaw and is accompanied by profuse sweating and nausea. Upon conducting an ECG, you observe ST-segment elevation in leads V2-V4, leading you to diagnose an anteroseptal ST-elevation myocardial infarction (MI). Can you identify the coronary vessel that runs along the interventricular septum on the anterior surface of the heart to reach the apex?
Your Answer:
Correct Answer: Left anterior descending artery
Explanation:The coronary arteries supply blood to the heart muscle, and blockages in these arteries can lead to heart attacks. The right coronary artery supplies the right side of the heart and is often associated with arrhythmias when blocked. The left circumflex artery supplies the left side of the heart and can cause lateral, posterior, or anterolateral heart attacks when blocked. The right marginal artery arises from the right coronary artery and travels along the bottom of the heart, while the left marginal artery arises from the left circumflex artery and travels along the curved edge of the heart.
The walls of each cardiac chamber are made up of the epicardium, myocardium, and endocardium. The heart and roots of the great vessels are related anteriorly to the sternum and the left ribs. The coronary sinus receives blood from the cardiac veins, and the aortic sinus gives rise to the right and left coronary arteries. The left ventricle has a thicker wall and more numerous trabeculae carnae than the right ventricle. The heart is innervated by autonomic nerve fibers from the cardiac plexus, and the parasympathetic supply comes from the vagus nerves. The heart has four valves: the mitral, aortic, pulmonary, and tricuspid valves.
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This question is part of the following fields:
- Cardiovascular System
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Question 19
Incorrect
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A 75-year-old woman is hospitalized with acute mesenteric ischemia. During a CT angiogram, a narrowing is observed at the point where the superior mesenteric artery originates. At what level does this artery branch off from the aorta?
Your Answer:
Correct Answer: L1
Explanation:The inferior pancreatico-duodenal artery is the first branch of the SMA, which exits the aorta at L1 and travels beneath the neck of the pancreas.
The Superior Mesenteric Artery and its Branches
The superior mesenteric artery is a major blood vessel that branches off the aorta at the level of the first lumbar vertebrae. It supplies blood to the small intestine from the duodenum to the mid transverse colon. However, due to its more oblique angle from the aorta, it is more susceptible to receiving emboli than the coeliac axis.
The superior mesenteric artery is closely related to several structures, including the neck of the pancreas superiorly, the third part of the duodenum and uncinate process postero-inferiorly, and the left renal vein posteriorly. Additionally, the right superior mesenteric vein is also in close proximity.
The superior mesenteric artery has several branches, including the inferior pancreatico-duodenal artery, jejunal and ileal arcades, ileo-colic artery, right colic artery, and middle colic artery. These branches supply blood to various parts of the small and large intestine. An overview of the superior mesenteric artery and its branches can be seen in the accompanying image.
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This question is part of the following fields:
- Cardiovascular System
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Question 20
Incorrect
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A 47-year-old woman has a laparoscopic cholecystectomy as a day case procedure. The surgery proves to be more challenging than expected, and a drain is inserted at the surgical site. During recovery, the patient experiences a significant loss of 1800ml of visible blood into the drain. Which of the following outcomes is not expected?
Your Answer:
Correct Answer: Release of aldosterone via the Bainbridge reflex
Explanation:The Bainbridge reflex is a response where the heart rate is elevated due to the activation of atrial stretch receptors following a sudden infusion of blood.
The heart has four chambers and generates pressures of 0-25 mmHg on the right side and 0-120 mmHg on the left. The cardiac output is the product of heart rate and stroke volume, typically 5-6L per minute. The cardiac impulse is generated in the sino atrial node and conveyed to the ventricles via the atrioventricular node. Parasympathetic and sympathetic fibers project to the heart via the vagus and release acetylcholine and noradrenaline, respectively. The cardiac cycle includes mid diastole, late diastole, early systole, late systole, and early diastole. Preload is the end diastolic volume and afterload is the aortic pressure. Laplace’s law explains the rise in ventricular pressure during the ejection phase and why a dilated diseased heart will have impaired systolic function. Starling’s law states that an increase in end-diastolic volume will produce a larger stroke volume up to a point beyond which stroke volume will fall. Baroreceptor reflexes and atrial stretch receptors are involved in regulating cardiac output.
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This question is part of the following fields:
- Cardiovascular System
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Question 21
Incorrect
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A 42-year-old man arrives at the emergency department with complaints of palpitations and dizziness. He has been experiencing vomiting and diarrhoea for the past week and has also been suffering from muscle weakness and cramps for the last three days. The possibility of hypokalaemia is suspected, and an ECG is ordered. What ECG sign is indicative of hypokalaemia?
Your Answer:
Correct Answer: Small or inverted T waves
Explanation:Hypokalaemia, a condition characterized by low levels of potassium in the blood, can be detected through ECG features. These include the presence of U waves, small or absent T waves (which may occasionally be inverted), a prolonged PR interval, ST depression, and a long QT interval. The ECG image provided shows typical U waves and a borderline PR interval. To remember these features, one user suggests the following rhyme: In Hypokalaemia, U have no Pot and no T, but a long PR and a long QT.
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This question is part of the following fields:
- Cardiovascular System
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Question 22
Incorrect
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A 54-year-old man visits his GP for a routine check-up and physical examination. He has a medical history of hypertension and asthma but currently has no immediate concerns. He reports feeling healthy.
During the examination, the man appears to be in good health, with normal vital signs except for a high blood pressure reading of 160/90 mmHg. While listening to his heart, the GP detects an S4 heart sound and orders an ECG.
Which segment of the ECG corresponds to the S4 heart sound?Your Answer:
Correct Answer: P wave
Explanation:The S4 heart sound coincides with the P wave on an ECG. This is because the S4 sound is caused by the contraction of the atria against a stiff ventricle, which occurs just before the S1 sound. It is commonly heard in conditions such as aortic stenosis, hypertrophic cardiomyopathy, or hypertension. As the P wave represents atrial depolarization, it is the ECG wave that coincides with the S4 heart sound.
It is important to note that the QRS complex, which represents ventricular depolarization, is not associated with the S4 heart sound. Similarly, the ST segment, which is the interval between ventricular depolarization and repolarization, and T waves, which indicate ventricular repolarization, are not linked to the S4 heart sound.
Heart sounds are the sounds produced by the heart during its normal functioning. The first heart sound (S1) is caused by the closure of the mitral and tricuspid valves, while the second heart sound (S2) is due to the closure of the aortic and pulmonary valves. The intensity of these sounds can vary depending on the condition of the valves and the heart. The third heart sound (S3) is caused by the diastolic filling of the ventricle and is considered normal in young individuals. However, it may indicate left ventricular failure, constrictive pericarditis, or mitral regurgitation in older individuals. The fourth heart sound (S4) may be heard in conditions such as aortic stenosis, HOCM, and hypertension, and is caused by atrial contraction against a stiff ventricle. The different valves can be best heard at specific sites on the chest wall, such as the left second intercostal space for the pulmonary valve and the right second intercostal space for the aortic valve.
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This question is part of the following fields:
- Cardiovascular System
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Question 23
Incorrect
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A 65-year-old man arrives at the emergency department with a sudden onset of numbness in his right arm and leg. Upon examination, he displays reduced sensation and 3 out of 5 power in his right arm and leg. A head CT scan reveals ischaemia in the region of the left middle cerebral artery. Following initial treatment, he is considered unsuitable for clopidogrel and is instead given aspirin and other antiplatelet drug that functions by inhibiting phosphodiesterase.
What is the name of the additional antiplatelet medication that this patient is likely to have been prescribed alongside aspirin?Your Answer:
Correct Answer: Dipyridamole
Explanation:Dipyridamole is a medication that inhibits phosphodiesterase non-specifically and reduces the uptake of adenosine by cells. The symptoms and CT scan results of this patient suggest that they have experienced a stroke on the left side due to ischemia. According to the NICE 2010 guidelines, after confirming that the stroke is not hemorrhagic and providing initial treatment, patients are advised to take either clopidogrel or a combination of aspirin and dipyridamole, which acts as a phosphodiesterase inhibitor.
Heparins function by activating antithrombin III.
Ticagrelor and prasugrel act as antagonists of the P2Y12 adenosine diphosphate (ADP) receptor.
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.
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This question is part of the following fields:
- Cardiovascular System
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Question 24
Incorrect
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A 65-year-old woman is admitted with severe community-acquired pneumonia that progresses to sepsis and sepsis-driven atrial fibrillation. During examination, her blood pressure is unrecordable and a weak pulse is detected in her left arm. She reports experiencing weakness, numbness, and pain in her left arm, leading doctors to suspect an embolus. What is the embolus' direction of travel from her heart to her left arm?
Your Answer:
Correct Answer: Left atrium → Left ventricle → aortic arch → left subclavian artery → left axillary artery → left brachial artery
Explanation:The path of oxygenated blood is from the left atrium to the left ventricle, then through the aortic arch, left subclavian artery, left axillary artery, and finally the left brachial artery.
Vascular disorders of the upper limb are less common than those in the lower limb. The upper limb circulation can be affected by embolic events, stenotic lesions, inflammatory disorders, and venous diseases. The collateral circulation of the arterial inflow can impact disease presentation. Conditions include axillary/brachial embolus, arterial occlusions, Raynaud’s disease, upper limb venous thrombosis, and cervical rib. Treatment varies depending on the condition.
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This question is part of the following fields:
- Cardiovascular System
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Question 25
Incorrect
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A mother brings her 8-year-old son to the GP with a history of intermittent fevers, severe joint pain and feeling fatigued. Other than a recent absence from school for a sore throat, he has been well with no other past medical history of note.
On examination, there is a pansystolic murmur heard over the left 5th intercostal space.
Which organism is the most probable cause for the aforementioned symptoms?Your Answer:
Correct Answer: Streptococcus pyogenes
Explanation:An immunological reaction is responsible for the development of rheumatic fever.
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.
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This question is part of the following fields:
- Cardiovascular System
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Question 26
Incorrect
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A 67-year-old man with heart failure visits his physician and inquires about the factors that influence stroke volume. What interventions can enhance stroke volume in a healthy person?
Your Answer:
Correct Answer: Increased central venous pressure
Explanation:There are four factors that impact stroke volume: cardiac size, contractility, preload, and afterload. When someone has heart failure, their stroke volume decreases. If there is an increase in parasympathetic activation, it would lead to a reduction in contractility. Hypertension would increase afterload, which means the ventricle would have to work harder to pump blood into the aorta. If there is an increase in central venous pressure, it would lead to an increase in preload due to an increase in venous return.
The stroke volume refers to the amount of blood that is pumped out of the ventricle during each cycle of cardiac contraction. This volume is usually the same for both ventricles and is approximately 70ml for a man weighing 70Kg. To calculate the stroke volume, the end systolic volume is subtracted from the end diastolic volume. Several factors can affect the stroke volume, including the size of the heart, its contractility, preload, and afterload.
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This question is part of the following fields:
- Cardiovascular System
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Question 27
Incorrect
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Mrs. Green is a 64-year-old woman with colon cancer. She is undergoing adjuvant chemotherapy, however in the past six months has suffered four deep vein thrombosis (DVT) events, despite being optimally anticoagulated with the maximum dose of dabigatran. On one occasion she suffered a DVT during treatment with dalteparin (a low molecular weight heparin). She has been admitted with symptoms of another DVT.
What is the recommended treatment for her current DVT?Your Answer:
Correct Answer: Insert an inferior vena caval filter
Explanation:For patients with recurrent venous thromboembolic disease, an inferior vena cava filter may be considered. This is particularly relevant for patients with cancer who have experienced multiple DVTs despite being fully anticoagulated. Before considering an inferior vena cava filter, alternative treatments such as increasing the target INR to 3-4 for long-term high-intensity oral anticoagulant therapy or switching to LMWH should be considered. This recommendation is in line with NICE guidelines on the diagnosis, management, and thrombophilia testing of venous thromboembolic diseases. Prescribing apixaban, increasing the dose of dabigatran off-license, or prescribing Thrombo-Embolic Deterrent (TED) stockings are not appropriate solutions for this patient. Similarly, initiating end-of-life drugs and preparing the family is not indicated based on the clinical description provided.
Management of Pulmonary Embolism
Pulmonary embolism (PE) is a serious condition that requires prompt management. The National Institute for Health and Care Excellence (NICE) updated their guidelines on the management of venous thromboembolism (VTE) in 2020, with some key changes. One of the significant changes is the recommendation to use direct oral anticoagulants (DOACs) as the first-line treatment for most people with VTE, including those with active cancer. Another change is the increasing use of outpatient treatment for low-risk PE patients, determined by a validated risk stratification tool.
Anticoagulant therapy is the cornerstone of VTE management. The guidelines recommend using apixaban or rivaroxaban as the first-line treatment for PE, followed by LMWH, dabigatran, edoxaban, or a vitamin K antagonist (VKA) if necessary. For patients with active cancer, DOACs are now recommended instead of LMWH. The length of anticoagulation depends on whether the VTE was provoked or unprovoked, with treatment typically lasting for at least three months. Patients with unprovoked VTE may continue treatment for up to six months, depending on their risk of recurrence and bleeding.
In cases of haemodynamic instability, thrombolysis is recommended as the first-line treatment for massive PE with circulatory failure. Other invasive approaches may also be considered where appropriate facilities exist. Patients who have repeat pulmonary embolisms, despite adequate anticoagulation, may be considered for inferior vena cava (IVC) filters. However, the evidence base for IVC filter use is weak, and further studies are needed.
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This question is part of the following fields:
- Cardiovascular System
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Question 28
Incorrect
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A 68-year-old man is prescribed clopidogrel to manage his peripheral artery disease-related claudication pain. What is the mechanism of action of this medication?
Your Answer:
Correct Answer: Inhibits ADP binding to platelet receptors
Explanation:Clopidogrel prevents clot formation by blocking the binding of ADP to platelet receptors. Factor Xa inhibitors like rivaroxaban directly inhibit factor Xa and are used to prevent and treat venous thromboembolism and atherothrombotic events. Dabigatran, a direct thrombin inhibitor, is used for prophylaxis and treatment of venous thromboembolism. Heparin/LMWH increase the effect of antithrombin and can be used to treat acute peripheral arterial occlusion, prevent and treat deep vein thrombosis and pulmonary embolism.
Clopidogrel: An Antiplatelet Agent for Cardiovascular Disease
Clopidogrel is a medication used to manage cardiovascular disease by preventing platelets from sticking together and forming clots. It is commonly used in patients with acute coronary syndrome and is now also recommended as a first-line treatment for patients following an ischaemic stroke or with peripheral arterial disease. Clopidogrel belongs to a class of drugs called thienopyridines, which work in a similar way. Other examples of thienopyridines include prasugrel, ticagrelor, and ticlopidine.
Clopidogrel works by blocking the P2Y12 adenosine diphosphate (ADP) receptor, which prevents platelets from becoming activated. However, concurrent use of proton pump inhibitors (PPIs) may make clopidogrel less effective. The Medicines and Healthcare products Regulatory Agency (MHRA) issued a warning in July 2009 about this interaction, and although evidence is inconsistent, omeprazole and esomeprazole are still cause for concern. Other PPIs, such as lansoprazole, are generally considered safe to use with clopidogrel. It is important to consult with a healthcare provider before taking any new medications or supplements.
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This question is part of the following fields:
- Cardiovascular System
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Question 29
Incorrect
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An 82-year-old woman visits her doctor with a medical history of myocardial infarction that has resulted in permanent damage to the conduction system of her heart. The damage has affected the part of the conduction system with the highest velocities, causing desynchronisation of the ventricles.
What is the part of the heart that conducts the fastest?Your Answer:
Correct Answer: Purkinje fibres
Explanation:The Purkinje fibres have the highest conduction velocities in the heart’s electrical conduction system. The process starts with the SA node generating spontaneous action potentials, which are then conducted across both atria through cell to cell conduction at a speed of approximately 1 m/s. The only pathway for the action potential to enter the ventricles is through the AV node, which has a slow conduction speed of 0.05ms to allow for complete atrial contraction and ventricular filling. The action potentials are then conducted through the Bundle of His, which splits into the left and right bundle branches, with a conduction speed of approximately 2m/s. Finally, the action potential reaches the Purkinje fibres, which are specialized conducting cells that allow for a faster conduction speed of 2-4m/s. This fast conduction speed is crucial for a synchronized and efficient contraction of the ventricle, generating pressure during systole.
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.
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This question is part of the following fields:
- Cardiovascular System
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Question 30
Incorrect
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A 49-year-old man arrived at the emergency department with chest discomfort persisting for 2 hours and flu-like symptoms for the past 4 days. His ECG revealed widespread ST-segment alterations. The cTnI test showed elevated values for this particular troponin subunit. What is the most precise explanation of the role of this subunit?
Your Answer:
Correct Answer: Binding to actin to hold the troponin-tropomyosin complex in place
Explanation:The function of troponin I is to bind to actin and hold the troponin-tropomyosin complex in place.
Understanding Troponin: The Proteins Involved in Muscle Contraction
Troponin is a group of three proteins that play a crucial role in the contraction of skeletal and cardiac muscles. These proteins work together to regulate the interaction between actin and myosin, which is essential for muscle contraction. The three subunits of troponin are troponin C, troponin T, and troponin I.
Troponin C is responsible for binding to calcium ions, which triggers the contraction of muscle fibers. Troponin T binds to tropomyosin, forming a complex that helps regulate the interaction between actin and myosin. Finally, troponin I binds to actin, holding the troponin-tropomyosin complex in place and preventing muscle contraction when it is not needed.
Understanding the role of troponin is essential for understanding how muscles work and how they can be affected by various diseases and conditions. By regulating the interaction between actin and myosin, troponin plays a critical role in muscle contraction and is a key target for drugs used to treat conditions such as heart failure and skeletal muscle disorders.
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This question is part of the following fields:
- Cardiovascular System
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