Pulmonary Hypertension — MCQs
All are causes of pulmonary hypertension except which of the following?
Which of the following drugs can be given in patients of primary pulmonary hypertension?
A 35-year-old female patient with class II pulmonary hypertension presents with a negative vasoreactive test. Which of the following is used in the next step of management?
During exercise the cardiac output rises up to 5 times, but the rise in pulmonary vascular resistance is only a few mm Hg. Why?
Which of the following best describes hypoxic pulmonary vasoconstriction?
Which of the following statements about pheochromocytoma is true?
A young patient presented with hypertension and a 24-hour urinary metanephrine level of 1.4 mg, the most likely causes are -
What is the primary effect of beta blockers in the management of thyroid storm?
ASD is associated with all except
A 30-year-old female presents with exertional dyspnea and a loud P2 on auscultation. What is the most likely diagnosis?
Pulmonary Hypertension Indian Medical PG Practice Questions and MCQs
Question 1: All are causes of pulmonary hypertension except which of the following?
- A. High altitude
- B. Fenfluramine
- C. Morbid obesity
- D. Hyperventilation (Correct Answer)
Explanation: ***Hyperventilation*** - **Hyperventilation** leads to a decrease in arterial carbon dioxide (PaCO2), causing **respiratory alkalosis** [1]. - This alkalosis induces **pulmonary vasodilation**, which tends to decrease rather than increase pulmonary arterial pressure. *Morbid obesity* - **Morbid obesity** often leads to **obesity hypoventilation syndrome (OHS)**, characterized by chronic hypoxemia and hypercapnia. - The resulting **chronic hypoxemia** causes sustained pulmonary vasoconstriction, leading to pulmonary hypertension. *High altitude* - Living at **high altitude** exposes individuals to **chronic hypoxia** due to lower atmospheric partial pressure of oxygen [3]. - This triggers **hypoxic pulmonary vasoconstriction** as a physiological response, which over time can remodel the pulmonary vasculature and lead to pulmonary hypertension [2]. *Fenfluramine* - **Fenfluramine** is an appetite suppressant that was historically linked to the development of pulmonary hypertension. - It causes an increase in pulmonary vascular resistance through various mechanisms, including enhancing the release and inhibiting the reuptake of **serotonin**, a potent pulmonary vasoconstrictor.
Question 2: Which of the following drugs can be given in patients of primary pulmonary hypertension?
- A. Icatibant
- B. Bosentan (Correct Answer)
- C. Sodium nitroprusside
- D. Labetalol
Explanation: ***Bosentan*** - **Bosentan** is an **endothelin receptor antagonist** that blocks the vasoconstrictive and proliferative effects of endothelin-1, a key mediator in the pathogenesis of **pulmonary hypertension**. - It is an FDA-approved medication specifically used for the treatment of **pulmonary arterial hypertension (PAH)**, improving exercise capacity and delaying clinical worsening. *Icatibant* - **Icatibant** is a **bradykinin B2 receptor antagonist** used in the treatment of **hereditary angioedema**. - It has no known role or efficacy in the management of **primary pulmonary hypertension**. *Labetalol* - **Labetalol** is a **beta-blocker** with **alpha-1 adrenergic blocking activity** used primarily for systemic **hypertension** and **hypertensive emergencies**. - Beta-blockers are generally **contraindicated** in pulmonary hypertension as they can worsen right heart function and lead to clinical deterioration. *Sodium nitroprusside* - **Sodium nitroprusside** is a **direct arterial and venous vasodilator** used in hypertensive crises and severe heart failure by reducing both preload and afterload. - While it can lower systemic blood pressure, its use in pulmonary hypertension is **limited** due to the risk of **systemic hypotension** and the lack of selective pulmonary vasodilation compared to other agents.
Question 3: A 35-year-old female patient with class II pulmonary hypertension presents with a negative vasoreactive test. Which of the following is used in the next step of management?
- A. Epoprostenol
- B. Nifedipine
- C. Iloprost
- D. Ambrisentan (Correct Answer)
Explanation: ***Ambrisentan*** - For patients with **Class II pulmonary hypertension** and a **negative vasoreactive test**, initial management typically involves **endothelin receptor antagonists (ERAs)**, phosphodiesterase-5 inhibitors (PDE5i), or guanylate cyclase stimulators (GCS). - **Ambrisentan** is an ERA that improves exercise capacity and delays clinical worsening in these patients. *Epoprostenol* - This is a **parenteral prostacyclin analog** reserved for patients with more severe pulmonary hypertension (WHO Class III or IV) or those who fail initial oral therapy. - Due to its continuous intravenous infusion, **high cost**, and side effects, it is not a first-line treatment for Class II PH. *Nifedipine* - **Calcium channel blockers (CCBs)** like nifedipine are only indicated for patients with a **positive vasoreactive test**, as they selectively dilate pulmonary arteries in these individuals. - For patients with a negative vasoreactive test, CCBs are **ineffective** and can be harmful due to systemic vasodilation causing hypotension. *Iloprost* - **Iloprost** is an inhaled prostacyclin analog used for patients with moderate to severe pulmonary hypertension (WHO Class III or IV), often in combination with other therapies. [1] - Its **inhalation route** and frequent dosing make it less practical for initial management of Class II disease compared to oral agents.
Question 4: During exercise the cardiac output rises up to 5 times, but the rise in pulmonary vascular resistance is only a few mm Hg. Why?
- A. Sympathetic stimulation causing vasodilatation
- B. Pulmonary vasoconstriction
- C. Opening of parallel channels (Correct Answer)
- D. J receptors
Explanation: ***Opening of parallel channels*** - During exercise, increased cardiac output leads to increased pulmonary blood flow, which triggers the **recruitment** (opening) of previously closed pulmonary capillaries. - This recruitment of additional parallel vascular channels effectively **decreases total pulmonary vascular resistance**, preventing a significant rise in pulmonary arterial pressure despite the greatly increased flow. *Sympathetic stimulation causing vasodilatation* - While sympathetic stimulation is crucial during exercise, it generally causes **vasoconstriction in systemic circulation** to redistribute blood flow. - Pulmonary circulation is unique; its vessels have a relatively minor response to sympathetic stimulation and typically do not undergo significant **sympathetic-mediated vasodilatation** that would solely account for such a large reduction in resistance. *Pulmonary vasoconstriction* - Pulmonary vasoconstriction would **increase** pulmonary vascular resistance, which is the opposite of what is observed during exercise. - Local factors like **hypoxia** can cause pulmonary vasoconstriction, but during exercise, ventilation increases to maintain adequate oxygenation, making widespread hypoxia unlikely in healthy individuals. *J receptors* - **Juxtacapillary (J) receptors** are sensory nerve endings in the alveolar walls that respond to conditions like pulmonary edema or emboli, causing reflex responses such as rapid, shallow breathing and bradycardia. - They do not play a direct role in the regulation of **pulmonary vascular resistance** in response to increased cardiac output during exercise.
Question 5: Which of the following best describes hypoxic pulmonary vasoconstriction?
- A. Reversible pulmonary vasoconstriction due to hypoxia (Correct Answer)
- B. Irreversible pulmonary vasoconstriction due to hypoxia
- C. Redirects blood to well-ventilated areas
- D. Occurs immediately in response to hypoxia
Explanation: ***Reversible pulmonary vasoconstriction due to hypoxia*** - Hypoxic pulmonary vasoconstriction (HPV) is a physiological response in which **pulmonary arterioles constrict** in areas of the lung with low oxygen levels. - This mechanism is **reversible**, meaning that when oxygen levels improve, the constricted vessels will dilate again. - The underlying mechanism involves hypoxia-induced inhibition of voltage-gated K⁺ channels in pulmonary arterial smooth muscle, leading to membrane depolarization, Ca²⁺ influx, and smooth muscle contraction. *Irreversible pulmonary vasoconstriction due to hypoxia* - This statement is incorrect because HPV is fundamentally a **reversible process**, designed to adapt to transient changes in alveolar oxygen. - Irreversible vasoconstriction typically occurs in chronic hypoxia, leading to **pulmonary hypertension** and structural remodeling (vascular remodeling with medial hypertrophy), which is a pathological state rather than the acute physiological response of HPV. *Redirects blood to well-ventilated areas* - While this is the **physiological purpose** and overall effect of hypoxic pulmonary vasoconstriction, it describes the functional outcome rather than what HPV fundamentally is. - The redirection of blood flow is the **consequence** of vasoconstriction in hypoxic areas, which optimizes ventilation-perfusion matching. *Occurs immediately in response to hypoxia* - While HPV does begin rapidly in response to hypoxia (within seconds to minutes), this describes the **timing characteristic** rather than what HPV is. - This statement is also somewhat imprecise, as the response involves intracellular signaling pathways that take time to manifest fully, though the onset is relatively quick compared to other vascular responses.
Question 6: Which of the following statements about pheochromocytoma is true?
- A. Arises from chromaffin cells of adrenal medulla (Correct Answer)
- B. Bilateral in 20% of all cases
- C. Hypotension rules out pheochromocytoma
- D. Almost always a malignant tumor
Explanation: ***Arises from chromaffin cells of adrenal medulla*** - **Pheochromocytomas** are rare neuroendocrine tumors that develop from **chromaffin cells** found in the adrenal medulla. - These cells are responsible for synthesizing and secreting **catecholamines**, explaining the characteristic symptoms of pheochromocytoma. *Bilateral in 20% of all cases* - While pheochromocytomas can be bilateral, this occurs in about **10% of cases**, mostly associated with genetic syndromes like **MEN 2**. - A higher percentage of bilaterality is seen in **familial forms** of the disease, but not in all cases. *Hypotension rules out pheochromocytoma* - Although **hypertension** is a hallmark symptom, **hypotension** can occur, particularly **orthostatic hypotension** due to volume depletion and impaired vasoconstriction. - Rarely, **pheochromocytoma crisis** can present with **shock** due to massive catecholamine release and subsequent myocardial dysfunction or vasoplegia. *Almost always a malignant tumor* - Most pheochromocytomas are **benign**; only about **10-15%** are malignant. - Malignancy is suggested by the presence of **metastatic disease**, as histology alone cannot reliably differentiate between benign and malignant forms.
Question 7: A young patient presented with hypertension and a 24-hour urinary metanephrine level of 1.4 mg, the most likely causes are -
- A. Grave's disease
- B. Pseudohypoparathyroidism
- C. Medullary carcinoma thyroid
- D. VonHippelLindau syndrome (Correct Answer)
Explanation: ***Von Hippel-Lindau syndrome*** - This syndrome is a **hereditary condition** predisposing individuals to various tumors, including **pheochromocytomas**, which cause elevated **metanephrines** and hypertension. - The combination of **hypertension** in a young patient and an elevated **24-hour urinary metanephrine level** (indicating excessive catecholamine production) strongly suggests a pheochromocytoma, which is frequently associated with Von Hippel-Lindau syndrome. *Medullary carcinoma thyroid* - This cancer is associated with **MEN 2 syndromes** and produces **calcitonin**, leading to hypocalcemia, but not typically elevated metanephrines or hypertension directly from the thyroid. - While it can be associated with **pheochromocytoma** (as part of MEN 2), it is not the direct cause of the elevated metanephrines. *Grave's disease* - **Grave's disease** is an autoimmune disorder causing **hyperthyroidism**, characterized by symptoms like goiter, exophthalmos, and weight loss. - While it can cause hypertension due to increased cardiac output, it does not lead to elevated **urinary metanephrine levels**, which are specific to catecholamine excess. *Pseudohypoparathyroidism* - This is a genetic disorder characterized by **target organ resistance to parathyroid hormone (PTH)**, leading to hypocalcemia and hyperphosphatemia [1]. - It does not cause hypertension or elevated **urinary metanephrine levels**.
Question 8: What is the primary effect of beta blockers in the management of thyroid storm?
- A. Increases metabolism of thyroxine
- B. Blocks thyroxine receptors
- C. Decreases synthesis of thyroxine
- D. Provides rapid relief of symptoms (Correct Answer)
Explanation: Detailed management of thyrotoxic crisis (thyroid storm) is a medical emergency where patients should be given propranolol, either oral or intravenous, to manage life-threatening symptoms [1]. ***Provides rapid relief of symptoms*** - Beta blockers primarily address the **adrenergic manifestations** of thyroid storm, such as **tachycardia**, **tremors**, anxiety, and palpitations [1]. - By blocking **beta-adrenergic receptors**, they provide rapid symptomatic relief and reduce cardiovascular stress, without affecting hormone levels [2]. Thyroid hormones normally increase the expression of genes for beta-adrenergic receptors and G-proteins, leading to increased heart rate and force of contraction [2]. *Increases metabolism of thyroxine* - Beta blockers do not increase the **metabolism** or breakdown of thyroxine; their action is primarily on the **peripheral effects** of thyroid hormones. - While some beta blockers like **propranolol** can inhibit the peripheral conversion of T4 to T3, this is a secondary effect and not their primary role in providing rapid symptomatic relief [1]. *Blocks thyroxine receptors* - Beta blockers do not block **thyroxine receptors**; thyroid hormones exert their effects by binding to intracellular receptors, not adrenergic receptors [2]. - Their action is on the **adrenergic system**, which is overstimulated by the high levels of thyroid hormones. *Decreases synthesis of thyroxine* - Beta blockers do not directly decrease the **synthesis of thyroxine** by the thyroid gland. - That action is performed by **antithyroid drugs** like methimazole and propylthiouracil, which inhibit hormone production [1].
Question 9: ASD is associated with all except
- A. Arrhythmia
- B. Infective endocarditis (Correct Answer)
- C. Stroke
- D. Pulmonary hypertension
Explanation: ***Infective endocarditis*** - **Atrial septal defects (ASDs)** are generally not associated with an increased risk of **infective endocarditis (IE)** due to the low-velocity, non-turbulent flow across the defect [1]. - The risk of IE in uncorrected ASDs is similar to that of the general population, and **prophylaxis** is typically not recommended [1]. *Arrhythmia* - **Atrial septal defects**, particularly secundum defects, are associated with a higher incidence of **atrial arrhythmias** later in life, such as atrial fibrillation and atrial flutter [1]. - This is due to **atrial enlargement** and remodeling caused by chronic volume overload. *Stroke* - An **atrial septal defect** can allow for **paradoxical emboli** to cross from the venous circulation to the arterial circulation, increasing the risk of **ischemic stroke**. - This is particularly true for ASDs with **right-to-left shunting** or in the presence of a patent foramen ovale (PFO). *Pulmonary hypertension* - Long-standing, uncorrected **atrial septal defects** can lead to chronic left-to-right shunting, causing **pulmonary overcirculation** [1]. - This chronic volume overload in the pulmonary vasculature can eventually lead to **pulmonary hypertension** and, in severe cases, Eisenmenger syndrome.
Question 10: A 30-year-old female presents with exertional dyspnea and a loud P2 on auscultation. What is the most likely diagnosis?
- A. Pulmonary hypertension (Correct Answer)
- B. Pericarditis
- C. Mitral regurgitation
- D. Aortic stenosis
Explanation: ***Pulmonary hypertension*** - **Exertional dyspnea** and a **loud P2** (pulmonic component of the second heart sound) are classic signs of elevated pressures in the pulmonary circulation [1]. - A loud P2 specifically indicates **pulmonary arterial hypertension**, suggesting increased resistance to blood flow in the pulmonary arteries [1]. *Pericarditis* - Characterized by **pleuritic chest pain** that improves when leaning forward and a **pericardial friction rub** on auscultation. - While it can cause dyspnea, it typically does not present with a loud P2 and is not primarily an exertional symptom. *Mitral regurgitation* - Presents with a **holosystolic murmur** best heard at the apex and radiating to the axilla, along with symptoms of heart failure. - While dyspnea is common, a loud P2 is not a primary diagnostic feature; instead, findings often relate to left atrial and ventricular overload. *Aortic stenosis* - Typically causes **exertional dyspnea**, **angina**, and **syncope**, with a **crescendo-decrescendo systolic murmur** loudest at the right upper sternal border [2]. - Its hallmark auscultatory finding is usually a harsh systolic murmur, and a loud P2 is not a characteristic sign.
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