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Question 1
Incorrect
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A 68-year-old female complains of fatigue and occasional palpitations. During one of these episodes, an ECG shows atrial fibrillation that resolves within half an hour. What would be the most suitable subsequent investigation for this patient?
Your Answer: 24 hour ECG monitoring
Correct Answer: Thyroid function tests
Explanation:Diagnosis and Potential Causes of Paroxysmal Atrial Fibrillation
Paroxysmal atrial fibrillation (AF) can have various underlying causes, including thyrotoxicosis, mitral stenosis, ischaemic heart disease, and alcohol consumption. Therefore, it is crucial to conduct thyroid function tests to aid in the diagnosis of AF, as it can be challenging to identify based solely on clinical symptoms. Additionally, an echocardiogram should be requested to evaluate the function of the left ventricle and valves, which would typically be performed by a cardiologist. However, coronary angiography is unlikely to be necessary.
Conversely, a full blood count, calcium, erythrocyte sedimentation rate (ESR), or lipid profile would not be useful in determining the nature of AF or its potential treatment. It is essential to consider the various causes of AF to determine the most effective course of treatment. The sources cited in this article provide further information on the diagnosis and management of AF.
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This question is part of the following fields:
- Cardiovascular System
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Question 2
Incorrect
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A 55-year-old man with several cardiac risk factors arrives at the hospital with sudden onset chest pain in the center. The pain extends to his left arm and is accompanied by sweating and nausea.
The patient's ECG reveals widespread T-wave inversion, which is a new finding compared to his previous ECGs. The level of troponin I in his serum is measured and confirmed to be elevated. The patient is initiated on treatment for acute coronary syndrome and transferred to a cardiac center.
What is the target of this measured cardiac biomarker?Your Answer: Myoglobin
Correct Answer: Actin
Explanation:Troponin I is a cardiac biomarker that binds to actin, which holds the troponin-tropomyosin complex in place and regulates muscle contraction. It is the standard biomarker used in conjunction with ECGs and clinical findings to diagnose non-ST elevation myocardial infarction (NSTEMI). Troponin I is highly sensitive and specific for myocardial damage compared to other cardiac biomarkers. Troponin C, another subunit of troponin, plays a role in Ca2+-dependent regulation of muscle contraction and can also be used in the diagnosis of myocardial infarction, but it is less specific as it is found in both cardiac and skeletal muscle. Copeptin, an amino acid peptide, is released earlier than troponin during acute myocardial infarction but is not widely used in clinical practice and has no interaction with troponin. Myoglobin, an iron- and oxygen-binding protein found in both cardiac and skeletal muscle, has poor specificity for cardiac injury and is not involved in the troponin-tropomyosin complex.
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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Question 3
Correct
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A 55-year-old female is referred to the cardiologist by her GP due to experiencing postural dyspnoea and leg oedema for a few months. The cardiologist conducts an echocardiogram and finds out that her left ventricular ejection fraction is 34%. Based on her clinical presentation, she is diagnosed with congestive cardiac failure.
To alleviate her symptoms and improve her long-term prognosis, the patient is prescribed several medications. However, she visits the GP after two weeks, complaining of a dry, tickling cough that she attributes to one of her new medications.
Which medication is most likely causing this new symptom in the patient?Your Answer: Ramipril (ACE inhibitor)
Explanation: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 4
Incorrect
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A 50-year-old man is brought to the emergency department following a collapse on the street. Upon examination, he displays visual and oculomotor deficits, but his motor function remains intact. Digital subtraction angiography reveals a basilar artery occlusion at the point where the vertebral arteries merge to form the basilar artery. What anatomical feature corresponds to the location of the occlusion?
Your Answer: The apex of the midbrain
Correct Answer: The base of the pons
Explanation:The basilar artery is formed by the union of the vertebral arteries at the base of the pons.
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 5
Incorrect
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A 14-year-old male immigrant from India visits his primary care physician complaining of gradually worsening shortness of breath, particularly during physical exertion, and widespread joint pain. He had a severe untreated throat infection in the past, but his vaccination record is complete. During the physical examination, a high-pitched holosystolic murmur is heard at the apex with radiation to the axilla.
Hemoglobin: 135 g/L
Platelets: 150 * 10^9/L
White blood cells: 9.5 * 10^9/L
Anti-streptolysin O titers: >200 units/mL
What is the most probable histological finding in his heart?Your Answer: Mallory bodies
Correct Answer: Aschoff bodies
Explanation:Rheumatic heart fever is characterized by the presence of Aschoff bodies, which are granulomatous nodules. The mitral valve is commonly affected in this condition, and an elevated ASO titre indicates exposure to group A streptococcus bacteria. Rheumatic heart disease is also associated with the presence of Anitschkow cells, which are enlarged macrophages with an ovoid, wavy, rod-like nucleus. Other types of bodies seen in different conditions include Councilman bodies in hepatitis C and yellow fever, Mallory bodies in alcoholism affecting hepatocytes, and Call-Exner bodies in granulosa cell tumours.
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 6
Incorrect
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An 80-year-old woman came in with an acute myocardial infarction. The ECG revealed ST segment elevation in leads II, III, and aVF. Which coronary artery is the most probable to be blocked?
Your Answer: Left coronary artery
Correct Answer: Right coronary artery
Explanation:Localisation of Myocardial Infarction
Myocardial infarction (MI) is a medical emergency that occurs when there is a blockage in the blood flow to the heart muscle. The location of the blockage determines the type of MI and the treatment required. An inferior MI is caused by the occlusion of the right coronary artery, which supplies blood to the bottom of the heart. This type of MI can cause symptoms such as chest pain, shortness of breath, and nausea. It is important to identify the location of the MI quickly to provide appropriate treatment and prevent further damage to the heart muscle. Proper diagnosis and management can improve the patient’s chances of survival and reduce the risk of complications.
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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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A 55-year-old woman with resistant hypertension is currently on ramipril and amlodipine. The GP wants to add a diuretic that primarily acts on the distal convoluted tubule. What diuretic should be considered?
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.
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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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An individual in their mid-20s is identified to have a superior vena cava on the left side. What is the most probable route for blood from this system to reach the heart?
Your Answer: Via the azygos venous system and into the superior vena cava
Correct Answer: Via the coronary sinus
Explanation:The Superior Vena Cava: Anatomy, Relations, and Developmental Variations
The superior vena cava (SVC) is a large vein that drains blood from the head and neck, upper limbs, thorax, and part of the abdominal walls. It is formed by the union of the subclavian and internal jugular veins, which then join to form the right and left brachiocephalic veins. The SVC is located in the anterior margins of the right lung and pleura, and is related to the trachea and right vagus nerve posteromedially, and the posterior aspects of the right lung and pleura posterolaterally. The pulmonary hilum is located posteriorly, while the right phrenic nerve and pleura are located laterally on the right side, and the brachiocephalic artery and ascending aorta are located laterally on the left side.
Developmental variations of the SVC are recognized, including anomalies of its connection and interruption of the inferior vena cava (IVC) in its abdominal course. In some individuals, a persistent left-sided SVC may drain into the right atrium via an enlarged orifice of the coronary sinus, while in rare cases, the left-sided vena cava may connect directly with the superior aspect of the left atrium, usually associated with an un-roofing of the coronary sinus. Interruption of the IVC may occur in patients with left-sided atrial isomerism, with drainage achieved via the azygos venous system.
Overall, understanding the anatomy, relations, and developmental variations of the SVC is important for medical professionals in diagnosing and treating related conditions.
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This question is part of the following fields:
- Cardiovascular System
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Question 9
Correct
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A 79-year-old man has just noticed that his heart is beating irregularly. Upon examination, his pulse is found to be irregularly irregular with a rate of 56 bpm. What ECG findings would you anticipate?
Your Answer: No P wave preceding each QRS complex
Explanation:Atrial Fibrillation and its Causes
Atrial fibrillation (AF) is a condition characterized by irregular heartbeats due to the constant activity of the atria. This can lead to the absence of distinct P waves, making it difficult to diagnose. AF can be caused by various factors such as hyperthyroidism, alcohol excess, mitral stenosis, and fibrous degeneration. The primary risks associated with AF are strokes and cardiac failure. Blood clots can form in the atria due to the lack of atrial movement, which can then be distributed into the systemic circulation, leading to strokes. High rates of AF can also cause syncopal episodes and cardiac failure.
The treatment of AF can be divided into controlling the rate or rhythm. If the rhythm cannot be controlled reliably, long-term anticoagulation with warfarin may be necessary to reduce the risk of stroke, depending on other risk factors. Bifid P waves are associated with hypertrophy of the left atrium, while regular P waves with no relation to QRS complexes are seen in complete heart block. Small P waves can be seen in hypokalaemia.
In cases of AF with shock, immediate medical attention is necessary, and emergency drug or electronic cardioversion may be needed. the causes and risks associated with AF is crucial in managing the condition and preventing complications.
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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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Sophie is a 22-year-old woman who was diagnosed with hypertrophic cardiomyopathy 4 years ago. Since then she has developed pulmonary hypertension which has added to her symptom load. To alleviate this, Sophie's doctor considers prescribing ambrisentan, an endothelin receptor antagonist. By inhibiting the mediator, endothelin, the doctor hopes to improve Sophie's symptoms until she receives a heart transplant.
What are the main physiological impacts of this mediator?Your Answer: Vasodilation and increased endovascular permeability
Correct Answer: Vasoconstriction and bronchoconstriction
Explanation:Endothelin is a potent vasoconstrictor and bronchoconstrictor that is secreted by endothelial cells and plays a crucial role in vascular homeostasis. However, excessive production of endothelin has been linked to various pathologies, including primary pulmonary hypertension. Inhibiting endothelin receptors can help lower pulmonary blood pressure.
It’s important to note that endothelin does not affect systemic vascular resistance or sodium excretion, which are regulated by atrial and ventricular natriuretic peptides. Aldosterone, on the other hand, is responsible for increasing sodium reabsorption in the kidneys, and it’s believed that endothelin and aldosterone may work together to regulate sodium homeostasis.
While endothelin causes vasoconstriction, it does not cause bronchodilation. Adrenaline, on the other hand, causes both vasoconstriction and bronchodilation, allowing for improved oxygen absorption from the lungs while delivering blood to areas of the body that require it for action.
Finally, endothelin does not increase endovascular permeability, which is a function of histamine released by mast cells in response to noxious stimuli. Histamine enhances the recruitment of leukocytes to an area of inflammation by causing vascular changes.
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
Correct
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A 67-year-old man is admitted for a below knee amputation. He is taking digoxin. The patient presents with an irregularly irregular pulse. What would be your expectation when examining the jugular venous pressure?
Your Answer: Absent a waves
Explanation:The pressure in the jugular vein.
Understanding Jugular Venous Pressure
Jugular venous pressure (JVP) is a useful tool for assessing right atrial pressure and identifying underlying valvular disease. The waveform of the jugular vein can provide valuable information about the heart’s function. A non-pulsatile JVP may indicate superior vena caval obstruction, while Kussmaul’s sign describes a paradoxical rise in JVP during inspiration seen in constrictive pericarditis.
The ‘a’ wave of the jugular vein waveform represents atrial contraction. A large ‘a’ wave may indicate conditions such as tricuspid stenosis, pulmonary stenosis, or pulmonary hypertension. However, an absent ‘a’ wave is common in atrial fibrillation.
Cannon ‘a’ waves are caused by atrial contractions against a closed tricuspid valve. They are seen in conditions such as complete heart block, ventricular tachycardia/ectopics, nodal rhythm, and single chamber ventricular pacing.
The ‘c’ wave represents the closure of the tricuspid valve and is not normally visible. The ‘v’ wave is due to passive filling of blood into the atrium against a closed tricuspid valve. Giant ‘v’ waves may indicate tricuspid regurgitation.
Finally, the ‘x’ descent represents the fall in atrial pressure during ventricular systole, while the ‘y’ descent represents the opening of the tricuspid valve. Understanding the jugular venous pressure waveform can provide valuable insights into the heart’s function and help diagnose underlying conditions.
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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 55-year-old man is having a radical gastrectomy for stomach cancer. What structure must be divided to access the coeliac axis during the procedure?
Your Answer: Gastrosplenic ligament
Correct Answer: Lesser omentum
Explanation:The division of the lesser omentum is necessary during a radical gastrectomy as it constitutes one of the nodal stations that must be removed.
The Coeliac Axis and its Branches
The coeliac axis is a major artery that supplies blood to the upper abdominal organs. It has three main branches: the left gastric, hepatic, and splenic arteries. The hepatic artery further branches into the right gastric, gastroduodenal, right gastroepiploic, superior pancreaticoduodenal, and cystic arteries. Meanwhile, the splenic artery gives off the pancreatic, short gastric, and left gastroepiploic arteries. Occasionally, the coeliac axis also gives off one of the inferior phrenic arteries.
The coeliac axis is located anteriorly to the lesser omentum and is related to the right and left coeliac ganglia, as well as the caudate process of the liver and the gastric cardia. Inferiorly, it is in close proximity to the upper border of the pancreas and the renal vein.
Understanding the anatomy and branches of the coeliac axis is important in diagnosing and treating conditions that affect the upper abdominal organs, such as pancreatic cancer or gastric ulcers.
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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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Which one of the following nerves is not found in the posterior triangle of the neck?
Your Answer: Accessory nerve
Correct Answer: Ansa cervicalis
Explanation:The anterior triangle of the neck contains the ansa cervicalis.
The posterior triangle of the neck is an area that is bound by the sternocleidomastoid and trapezius muscles, the occipital bone, and the middle third of the clavicle. Within this triangle, there are various nerves, vessels, muscles, and lymph nodes. The nerves present include the accessory nerve, phrenic nerve, and three trunks of the brachial plexus, as well as branches of the cervical plexus such as the supraclavicular nerve, transverse cervical nerve, great auricular nerve, and lesser occipital nerve. The vessels found in this area are the external jugular vein and subclavian artery. Additionally, there are muscles such as the inferior belly of omohyoid and scalene, as well as lymph nodes including the supraclavicular and occipital nodes.
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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 50-year-old man presents to the emergency department with excruciating chest pain that raises suspicion of aortic dissection. Which layers are the blood expected to be flowing between?
Your Answer: Tunica media and tunica adventitia
Correct Answer: Tunica intima and tunica media
Explanation:In an aortic dissection, the tunica intima becomes separated from the tunica media. The tunica intima is the innermost layer of a blood vessel, while the tunica media is the second layer and the tunica adventitia is the third layer. Normally, the tunica media would be situated between the tunica intima and adventitia in the aorta. Capillaries have layers called endothelium and basal laminae, while the internal and external elastic laminae are found on either side of the tunica media.
Artery Histology: Layers of Blood Vessel Walls
The wall of a blood vessel is composed of three layers: the tunica intima, tunica media, and tunica adventitia. The innermost layer, the tunica intima, is made up of endothelial cells that are separated by gap junctions. The middle layer, the tunica media, contains smooth muscle cells and is separated from the intima by the internal elastic lamina and from the adventitia by the external elastic lamina. The outermost layer, the tunica adventitia, contains the vasa vasorum, fibroblast, and collagen. This layer is responsible for providing support and protection to the blood vessel. The vasa vasorum are small blood vessels that supply oxygen and nutrients to the larger blood vessels. The fibroblast and collagen provide structural support to the vessel wall. Understanding the histology of arteries is important in diagnosing and treating various cardiovascular diseases.
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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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You are shadowing a cardiologist during a clinic session and the first patient is an 80-year-old man who has come for his annual check-up. He reports experiencing swollen ankles, increased shortness of breath, and difficulty sleeping flat. He has a history of heart failure but has been stable for the past 10 years. He believes that his condition has worsened since starting a new medication, but he cannot recall the name of the drug. Unfortunately, the electronic medical records are down, and you cannot access his medication history. Which of the following medications is most likely responsible for his symptoms?
Your Answer: Ramipril
Correct Answer: Hydralazine
Explanation:Hydralazine is unique among these drugs as it has been known to cause fluid retention by elevating the plasma concentration of renin. Conversely, the other drugs listed are recognized for their ability to reduce fluid overload and promote fluid elimination.
Hydralazine: An Antihypertensive with Limited Use
Hydralazine is an antihypertensive medication that is not commonly used nowadays. It is still prescribed for severe hypertension and hypertension in pregnancy. The drug works by increasing cGMP, which leads to smooth muscle relaxation. However, there are certain contraindications to its use, such as systemic lupus erythematosus and ischaemic heart disease/cerebrovascular disease.
Despite its potential benefits, hydralazine can cause adverse effects such as tachycardia, palpitations, flushing, fluid retention, headache, and drug-induced lupus. Therefore, it is not the first choice for treating hypertension in most cases. Overall, hydralazine is an older medication that has limited use due to its potential side effects and newer, more effective antihypertensive options available.
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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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You perform venepuncture on the basilic vein in the cubital fossa.
At which point does this vein pass deep under muscle?Your Answer: At the axilla
Correct Answer: Midway up the humerus
Explanation:When the basilic vein is located halfway up the humerus, it travels beneath muscle. At the cubital fossa, the basilic vein connects with the median cubital vein, which in turn interacts with the cephalic vein. Contrary to popular belief, the basilic vein does not pass through the medial epicondyle. Meanwhile, the cephalic vein can be found in the deltopectoral groove.
The Basilic Vein: A Major Pathway of Venous Drainage for the Arm and Hand
The basilic vein is one of the two main pathways of venous drainage for the arm and hand, alongside the cephalic vein. It begins on the medial side of the dorsal venous network of the hand and travels up the forearm and arm. Most of its course is superficial, but it passes deep under the muscles midway up the humerus. Near the region anterior to the cubital fossa, the basilic vein joins the cephalic vein.
At the lower border of the teres major muscle, the anterior and posterior circumflex humeral veins feed into the basilic vein. It is often joined by the medial brachial vein before draining into the axillary vein. The basilic vein is continuous with the palmar venous arch distally and the axillary vein proximally. Understanding the path and function of the basilic vein is important for medical professionals in diagnosing and treating conditions related to venous drainage in the arm and hand.
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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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As a young medical trainee participating in the ward round for diabetic foot, your consultant requests you to evaluate the existence of the posterior tibial pulse. Can you identify its location?
Your Answer: Superficial to the medial ankle
Correct Answer: Behind and below the medial ankle
Explanation:The lower limb has 4 primary pulse points, which include the femoral pulse located 2-3 cm below the mid-inguinal point, the popliteal pulse that can be accessed by partially flexing the knee to loosen the popliteal fascia, the posterior tibial pulse located behind and below the medial ankle, and the dorsal pedis pulse found on the dorsum of the foot.
Lower Limb Pulse Points
The lower limb has four main pulse points that are important to check for proper circulation. These pulse points include the femoral pulse, which can be found 2-3 cm below the mid-inguinal point. The popliteal pulse can be found with a partially flexed knee to lose the popliteal fascia. The posterior tibial pulse can be found behind and below the medial ankle, while the dorsal pedis pulse can be found on the dorsum of the foot. It is important to check these pulse points regularly to ensure proper blood flow to the lower limb. By doing so, any potential circulation issues can be detected early on and treated accordingly. Proper circulation is essential for maintaining healthy lower limbs and overall physical well-being.
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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 72-year-old male with a history of severe aortic stenosis undergoes valve replacement surgery. Following the procedure, he is prescribed dipyridamole. What is the mechanism of action of this medication?
Your Answer: P2Y12-receptor agonist
Correct Answer: Non-specific phosphodiesterase antagonist
Explanation:Dipyridamole is a non-specific phosphodiesterase antagonist that inhibits platelet aggregation and thrombus formation by elevating platelet cAMP levels. It also reduces cellular uptake of adenosine and inhibits thromboxane synthase.
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 19
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: Add apixaban to his prescription
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 20
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A 48-year-old man comes to the clinic for a hypertension follow-up. He was diagnosed with high blood pressure two months ago and started on ramipril. However, his blood pressure remained uncontrolled, so amlodipine was added to his treatment four weeks ago. Today, his blood pressure reading is 161/91mmHg. You decide to prescribe indapamide, a thiazide diuretic. Can you identify the primary site of action of thiazides in the nephron?
Your Answer: Ascending limb of the loop of Henle
Correct Answer: Distal convoluted tubule
Explanation:Thiazide diuretics, such as indapamide, work by blocking the Na+-Cl− symporter at the beginning of the distal convoluted tubule, which inhibits sodium reabsorption. Loop diuretics, on the other hand, inhibit Na+/K+ 2Cl- channels in the thick ascending loop of Henle. There are currently no diuretic agents that specifically target the descending limb of the loop of Henle. Carbonic anhydrase inhibitors prevent the exchange of luminal Na+ for cellular H+ in both the proximal and distal tubules. Potassium-sparing diuretics, such as amiloride, inhibit the Na+/K+ ATPase in the cortical collecting ducts either directly or by blocking aldosterone receptors, as seen in spironolactone.
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.
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This question is part of the following fields:
- Cardiovascular System
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