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  • Question 1 - A 25-year-old woman is having a trendelenberg procedure to treat her varicose veins....

    Incorrect

    • A 25-year-old woman is having a trendelenberg procedure to treat her varicose veins. While dissecting the saphenofemoral junction, which structure is most susceptible to injury?

      Your Answer: Superficial circumflex iliac vein

      Correct Answer: Deep external pudendal artery

      Explanation:

      The deep external pudendal artery is situated near the origin of the long saphenous vein and can be damaged. The highest risk of injury occurs during the flush ligation of the saphenofemoral junction. However, if an injury is detected and the vessel is tied off, it is rare for any significant negative consequences to occur.

      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
      77.6
      Seconds
  • Question 2 - A patient with chronic heart failure with reduced ejection fraction has been prescribed...

    Incorrect

    • A patient with chronic heart failure with reduced ejection fraction has been prescribed a new medication as part of their drug regimen. This drug aims to improve myocardial contractility, but it is also associated with various side effects, such as arrhythmias. Its mechanism of action is blocking a protein with an important role in the resting potential of cardiac muscle cells.

      What protein is the drug targeting?

      Your Answer: Ca2+ channels

      Correct Answer: Na+/K+ ATPases

      Explanation:

      Understanding the Cardiac Action Potential and Conduction Velocity

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

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

    • This question is part of the following fields:

      • Cardiovascular System
      103.2
      Seconds
  • Question 3 - A 65-year-old woman is admitted with severe community-acquired pneumonia that progresses to sepsis...

    Incorrect

    • 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: Left atrium → Left ventricle → aortic arch → left supraclavicular artery → left axillary artery → left brachial artery

      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.

    • This question is part of the following fields:

      • Cardiovascular System
      181.4
      Seconds
  • Question 4 - A 51-year-old woman has just had a right hemiarthroplasty and is now experiencing...

    Correct

    • A 51-year-old woman has just had a right hemiarthroplasty and is now experiencing sudden onset of shortness of breath and sharp pleuritic pain on the right side of her chest. A chest x-ray is done as part of the initial evaluation, revealing a wedge-shaped opacification. What is the probable diagnosis?

      Your Answer: Pulmonary embolism

      Explanation:

      Symptoms and Signs of Pulmonary Embolism

      Pulmonary embolism is a medical condition that can be difficult to diagnose due to its varied symptoms and signs. While chest pain, dyspnoea, and haemoptysis are commonly associated with pulmonary embolism, only a small percentage of patients present with this textbook triad. The symptoms and signs of pulmonary embolism can vary depending on the location and size of the embolism.

      The PIOPED study conducted in 2007 found that tachypnea, or a respiratory rate greater than 16/min, was the most common clinical sign in patients diagnosed with pulmonary embolism, occurring in 96% of cases. Other common signs included crackles in the chest (58%), tachycardia (44%), and fever (43%). Interestingly, the Well’s criteria for diagnosing a PE uses tachycardia rather than tachypnea. It is important for healthcare professionals to be aware of the varied symptoms and signs of pulmonary embolism to ensure prompt diagnosis and treatment.

    • This question is part of the following fields:

      • Cardiovascular System
      48.5
      Seconds
  • Question 5 - A 30-year-old man arrived at the emergency department following a syncopal episode during...

    Incorrect

    • A 30-year-old man arrived at the emergency department following a syncopal episode during a game of basketball. He is typically healthy with no prior medical history, but he does mention experiencing occasional palpitations, which he believes may be due to alcohol or caffeine consumption. Upon further inquiry, he reveals that his father passed away suddenly at the age of 40 due to a heart condition. What is the underlying pathophysiological alteration in this patient?

      Your Answer: Accessory pathway

      Correct Answer: Asymmetric septal hypertrophy

      Explanation:

      When a young patient presents with symptoms of syncope and chest discomfort, along with a family history of hypertrophic cardiomyopathy (HOCM), it is important to consider the possibility of this condition. Asymmetric septal hypertrophy and systolic anterior movement (SAM) of the anterior leaflet of the mitral valve on echocardiogram or cMR are supportive of HOCM. This condition is caused by a genetic defect in the beta-myosin heavy chain protein gene. While Brugada syndrome may also be a consideration, it is not listed as a possible answer due to its underlying mechanism of sodium channelopathy.

      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.

    • This question is part of the following fields:

      • Cardiovascular System
      112
      Seconds
  • Question 6 - A 12-year-old child presents to the emergency department with polyarthritis and chest pain...

    Incorrect

    • A 12-year-old child presents to the emergency department with polyarthritis and chest pain that is relieved by leaning forward. Blood tests reveal a raised ESR and leucocytosis, but are otherwise normal. The child's parents mention that they have never vaccinated their child as they themselves are unvaccinated and rarely fall ill. In light of this information, you decide to order an anti-streptolysin-O-titre to investigate for recent streptococcal infection. What is the immunological term used to describe the mechanism behind the development of this condition?

      Your Answer: Exposure of cryptic antigens

      Correct Answer: Molecular mimicry

      Explanation:

      Rheumatic fever is caused by molecular mimicry, where the M protein on the cell wall of Streptococcus pyogenes cross-reacts with myosin in the smooth muscles of arteries, leading to autoimmunity. This is evidenced by the patient’s symptoms of polyarthritis and chest pain, as well as the presence of anti-streptolysin-O-titre in their blood. Bystander activation, exposure to cryptic antigens, and super-antigens are all pathophysiological mechanisms that can lead to autoimmune destruction of tissues.

      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
      68.2
      Seconds
  • Question 7 - Which of the following is true about endothelin? ...

    Incorrect

    • Which of the following is true about endothelin?

      Your Answer: It is a potent vasodilator

      Correct Answer: Endothelin antagonists are useful in primary pulmonary hypertension

      Explanation:

      Antagonists are used in primary pulmonary hypertension because endothelin induced constriction of the pulmonary blood vessels.

      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.

    • This question is part of the following fields:

      • Cardiovascular System
      12.9
      Seconds
  • Question 8 - A 67-year-old man is brought to the emergency department with unilateral weakness and...

    Correct

    • A 67-year-old man is brought to the emergency department with unilateral weakness and loss of sensation. He is later diagnosed with an ischaemic stroke. After initial treatment, he is started on dipyridamole as part of his ongoing therapy.

      What is the mechanism of action of dipyridamole?

      Your Answer: Non-specific phosphodiesterase inhibitor

      Explanation:

      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
      16.9
      Seconds
  • Question 9 - A 75-year-old man presents to the emergency department following a syncopal episode. He...

    Correct

    • 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: 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
      25.5
      Seconds
  • Question 10 - A 45-year-old male with no past medical history is recently diagnosed with hypertension....

    Correct

    • 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.

    • This question is part of the following fields:

      • Cardiovascular System
      115.3
      Seconds
  • Question 11 - During ward round, you have been presented with an ECG of a 50-year-old...

    Incorrect

    • During ward round, you have been presented with an ECG of a 50-year-old female who was admitted with blackouts and a heart rate of 43bpm. On the ECG you note that the QRS complex is narrow but is missing after every other P wave. What is this condition called?

      Your Answer: First-degree heart block

      Correct Answer: 2:1 heart block

      Explanation:

      The patient has a bradycardia with a narrow QRS complex, ruling out bundle branch blocks. It is not a first-degree heart block or a Wenckebach heart block. The correct diagnosis is a 2:1 heart block with 2 P waves to each QRS complex.

      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
      13.3
      Seconds
  • Question 12 - 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: Glycoprotein IIb/IIIa inhibitor

      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
      183.4
      Seconds
  • Question 13 - A 65-year-old man visits the clinic for his regular blood work. The GP...

    Incorrect

    • A 65-year-old man visits the clinic for his regular blood work. The GP requests the medical student to perform venepuncture and obtain blood samples. The student seizes this chance to brush up on their knowledge of vascular anatomy. They plan to draw blood from the median cubital vein located in the antecubital fossa. While aware that the median cubital vein is linked to the cephalic vein, they cannot recall the name of the other vein it connects to. Can you identify the other vein?

      Your Answer: Brachial vein

      Correct Answer: Basilic vein

      Explanation:

      The upper limb has both superficial and deep veins. Among the superficial veins are the cephalic, basilic, and median cubital veins. The median cubital vein, which connects the cephalic and basilic veins, is situated in the antecubital fossa and is the preferred site for venepuncture because it is easy to locate and access. However, deep veins like the brachial, ulnar, and radial veins are not suitable for venepuncture as they are located beneath the deep fascia.

      The Cephalic Vein: Path and Connections

      The cephalic vein is a major blood vessel that runs along the lateral side of the arm. It begins at the dorsal venous arch, which drains blood from the hand and wrist, and travels up the arm, crossing the anatomical snuffbox. At the antecubital fossa, the cephalic vein is connected to the basilic vein by the median cubital vein. This connection is commonly used for blood draws and IV insertions.

      After passing through the antecubital fossa, the cephalic vein continues up the arm and pierces the deep fascia of the deltopectoral groove to join the axillary vein. This junction is located near the shoulder and marks the end of the cephalic vein’s path.

      Overall, the cephalic vein plays an important role in the circulation of blood in the upper limb. Its connections to other major veins in the arm make it a valuable site for medical procedures, while its path through the deltopectoral groove allows it to contribute to the larger network of veins that drain blood from the upper body.

    • This question is part of the following fields:

      • Cardiovascular System
      93.9
      Seconds
  • Question 14 - A 65-year-old man with a history of claudication for several years is evaluated...

    Correct

    • A 65-year-old man with a history of claudication for several years is evaluated in the clinic. A duplex scan reveals an 85% stenosis of the superficial femoral artery. After two weeks, he returns with a sudden onset of severe leg pain that has been present for an hour. Upon examination, absent pulses are noted in the affected limb, and it is significantly cooler than the opposite limb. What is the most likely cause of this presentation?

      Your Answer: Thrombosis

      Explanation:

      When dealing with an already present lesion, the probability of encountering a complication like thrombosis is higher than that of an embolus. To address this, patients should be administered heparin and undergo imaging with duplex scanning. Although an early surgical bypass or intra-arterial thrombolysis may be necessary, performing an embolectomy is generally not recommended as the lesion is not an embolus, rendering the operation ineffective.

      Understanding Claudication

      Claudication is a medical condition that causes pain in the limbs during physical activity. It is usually caused by arterial insufficiency, which occurs when atheroma develops in the arterial wall and blocks the blood flow to the tissues. The most common symptom of claudication is calf pain that worsens during exercise and improves with rest. However, if the disease is located in more proximal areas, other symptoms such as buttock claudication and impotence may occur.

      The condition usually develops progressively, and in severe cases, it can lead to critical limb ischemia, which is characterized by severe pain, diminished sensation, pallor, and absent pulses. Risk factors for claudication include smoking, diabetes, and hyperlipidemia.

      To diagnose claudication, doctors may measure ankle-brachial pressure indices, perform duplex scanning, or conduct formal angiography. Treatment options depend on the severity of the condition. Patients with long claudication distances and no ulceration or gangrene may be managed conservatively, while those with rest pain, ulceration, or gangrene will require intervention. All patients should receive an antiplatelet agent and a statin, unless there are compelling contraindications.

    • This question is part of the following fields:

      • Cardiovascular System
      125.1
      Seconds
  • Question 15 - A 60-year-old woman complains of persistent diarrhoea, wheezing, and flushing. During the physical...

    Correct

    • A 60-year-old woman complains of persistent diarrhoea, wheezing, and flushing. During the physical examination, an irregular pulsatile hepatomegaly and a pansystolic murmur that is most pronounced during inspiration are detected. What diagnostic test could provide insight into the probable underlying condition?

      Your Answer: Urinary 5-HIAA (5-hydroxyindole acetic acid)

      Explanation:

      Carcinoid Syndrome and its Diagnosis

      Carcinoid syndrome is characterized by the presence of vasoactive amines such as serotonin in the bloodstream, leading to various clinical features. The primary carcinoid tumor is usually found in the small intestine or appendix, but it may not cause significant symptoms as the liver detoxifies the blood of these amines. However, systemic effects occur when malignant cells spread to other organs, such as the lungs, which are not part of the portal circulation. One of the complications of carcinoid syndrome is damage to the right heart valves, which can cause tricuspid regurgitation, as evidenced by a pulsatile liver and pansystolic murmur.

      To diagnose carcinoid syndrome, the 5-HIAA test is usually performed, which measures the breakdown product of serotonin in a 24-hour urine collection. If the test is positive, imaging and histology are necessary to confirm malignancy.

    • This question is part of the following fields:

      • Cardiovascular System
      51.7
      Seconds
  • Question 16 - A young woman presents with symptoms indicative of infective endocarditis. She has no...

    Incorrect

    • A young woman presents with symptoms indicative of infective endocarditis. She has no history of injecting drug use, but her dentist notes that she has poor oral hygiene. What organism is most likely responsible for this infection?

      Your Answer: Staphylococcus aureus

      Correct Answer: Streptococci viridans

      Explanation:

      Infective endocarditis is most frequently caused by Streptococci viridans, which is commonly found in the oral cavity. This type of infection is often linked to patients with inadequate dental hygiene or those who have undergone dental procedures.

      Aetiology of Infective Endocarditis

      Infective endocarditis is a condition that affects patients with previously normal valves, rheumatic valve disease, prosthetic valves, congenital heart defects, intravenous drug users, and those who have recently undergone piercings. The strongest risk factor for developing infective endocarditis is a previous episode of the condition. The mitral valve is the most commonly affected valve.

      The most common cause of infective endocarditis is Staphylococcus aureus, particularly in acute presentations and intravenous drug users. Historically, Streptococcus viridans was the most common cause, but this is no longer the case except in developing countries. Coagulase-negative Staphylococci such as Staphylococcus epidermidis are commonly found in indwelling lines and are the most common cause of endocarditis in patients following prosthetic valve surgery. Streptococcus bovis is associated with colorectal cancer, with the subtype Streptococcus gallolyticus being most linked to the condition.

      Culture negative causes of infective endocarditis include prior antibiotic therapy, Coxiella burnetii, Bartonella, Brucella, and HACEK organisms (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella). It is important to note that systemic lupus erythematosus and malignancy, specifically marantic endocarditis, can also cause non-infective endocarditis.

    • This question is part of the following fields:

      • Cardiovascular System
      7
      Seconds
  • Question 17 - 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
      6
      Seconds
  • Question 18 - What is the equivalent of cardiac preload? ...

    Correct

    • What is the equivalent of cardiac preload?

      Your Answer: End diastolic volume

      Explanation:

      Preload, also known as end diastolic volume, follows the Frank Starling principle where a slight increase results in an increase in cardiac output. However, if preload is significantly increased, such as exceeding 250ml, it can lead to a decrease in cardiac output.

      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.

    • This question is part of the following fields:

      • Cardiovascular System
      9.4
      Seconds
  • Question 19 - A 63-year-old woman comes to her doctor for a review of her angina...

    Incorrect

    • A 63-year-old woman comes to her doctor for a review of her angina medication. She expresses worry about her condition and inquires about the cause of the narrowing of her coronary arteries.

      What alteration takes place during the progression of atherosclerosis?

      Your Answer: Phagocytosis of HDLs by macrophages, forming foam cells

      Correct Answer: Fatty infiltration of the subendothelial space

      Explanation:

      The subendothelial space is where fatty infiltration takes place.

      Foam cells are created by the ingestion of LDLs, not HDLs.

      Infiltration does not occur in the tunica externa, but rather in the subendothelial space.

      Smooth muscle proliferation occurs, not hypertrophy.

      Endothelial dysfunction leads to a decrease in nitric oxide bioavailability.

      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 then 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
      43.1
      Seconds
  • Question 20 - A 75-year-old collapses at home and is rushed to the Emergency Room but...

    Incorrect

    • A 75-year-old collapses at home and is rushed to the Emergency Room but dies despite resuscitation efforts. He had a myocardial infarction five weeks prior. What histological findings would be expected in his heart?

      Your Answer: Coagulative necrosis, neutrophils, wavy fibres, hypercontraction of myofibrils

      Correct Answer: Contracted scar

      Explanation:

      The histology findings of a myocardial infarction (MI) vary depending on the time elapsed since the event. Within the first 24 hours, early coagulative necrosis, neutrophils, wavy fibres, and hypercontraction of myofibrils are observed, which increase the risk of ventricular arrhythmia, heart failure, and cardiogenic shock. Between 1-3 days post-MI, extensive coagulative necrosis and neutrophils are present, which can lead to fibrinous pericarditis. From 3-14 days post-MI, macrophages and granulation tissue are seen at the margins, and there is a high risk of complications such as free wall rupture (resulting in mitral regurgitation), papillary muscle rupture, and left ventricular pseudoaneurysm. Finally, from 2 weeks to several months post-MI, a contracted scar is formed, which is associated with Dressler syndrome, heart failure, arrhythmias, and mural thrombus.

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

    • This question is part of the following fields:

      • Cardiovascular System
      15.7
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Cardiovascular System (7/20) 35%
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