Pathophysiology Quiz: Primary Vs Secondary Hypertension
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Primary Vs Secondary HypertensionQuestion 1 of 20

A patient with resistant hypertension is started on spironolactone, an aldosterone antagonist. Their blood pressure improves significantly, and their previously low serum potassium normalizes. Plasma renin activity remains suppressed.

These findings are most consistent with which underlying pathophysiologic state?

Renovascular hypertension with high renin and high aldosterone levels.
Primary (essential) hypertension with a high-renin profile.
Primary aldosteronism with autonomous, renin-independent aldosterone secretion.
Pheochromocytoma with catecholamine-induced activation of the RAAS.
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Pathophysiology Quiz

Pathophysiology Quiz: Primary Vs Secondary Hypertension

Practice Primary Vs Secondary Hypertension in Pathophysiology with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

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This quiz focuses on Primary Vs Secondary Hypertension, giving you a quick way to practice the rules, question types, and explanations that matter most for Pathophysiology.

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Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

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Question 1

A patient with resistant hypertension is started on spironolactone, an aldosterone antagonist. Their blood pressure improves significantly, and their previously low serum potassium normalizes. Plasma renin activity remains suppressed.

These findings are most consistent with which underlying pathophysiologic state?

  1. Renovascular hypertension with high renin and high aldosterone levels.
  2. Primary (essential) hypertension with a high-renin profile.
  3. Primary aldosteronism with autonomous, renin-independent aldosterone secretion. (correct answer)
  4. Pheochromocytoma with catecholamine-induced activation of the RAAS.
Explanation: The dramatic response to an aldosterone antagonist (spironolactone), coupled with the history of hypokalemia and suppressed renin, points strongly to primary aldosteronism. In this condition, an adrenal source produces aldosterone autonomously, independent of the RAAS. This leads to hypertension and hypokalemia. Blocking the aldosterone receptor directly addresses the root cause. The renin level remains suppressed because the underlying volume expansion and hypertension are not corrected, they are just blocked at the receptor level, so the kidney still senses high pressure and suppresses renin release.

Question 2

A patient with long-standing primary hypertension develops proteinuria and a modest elevation in serum creatinine. How does the pathophysiology of primary hypertension contribute to the development of this nephropathy?

  1. Systemic hypertension causes efferent arteriolar constriction, reducing glomerular filtration pressure and leading to ischemia.
  2. Increased renal perfusion from high systemic pressure leads to compensatory afferent vasodilation and glomerular hypertrophy.
  3. High systemic pressure is transmitted to the glomeruli, causing barotrauma, endothelial injury, and glomerulosclerosis. (correct answer)
  4. Chronic activation of the parasympathetic nervous system causes renal artery stenosis and subsequent parenchymal damage.
Explanation: In primary hypertension, the protective autoregulatory mechanism of the afferent arteriole can be overwhelmed. The high systemic pressure is transmitted to the delicate glomerular capillaries, causing mechanical stress (barotrauma). This leads to endothelial injury, increased permeability to proteins (proteinuria), and a chronic inflammatory and fibrotic response that results in glomerulosclerosis and a progressive decline in renal function.

Question 3

A 10-year-old child is evaluated for hypertension. On examination, the brachial artery blood pressure is 150/90 mmHg, while the popliteal artery pressure is 110/75 mmHg. Femoral pulses are weak and delayed compared to radial pulses.

This patient's hypertension is primarily a consequence of which pathophysiological mechanism?

  1. Increased stroke volume due to a patent ductus arteriosus causing a wide pulse pressure.
  2. Reduced perfusion pressure to the kidneys, leading to potent activation of the renin-angiotensin-aldosterone system. (correct answer)
  3. A generalized genetic defect in vascular smooth muscle tone affecting all major arteries.
  4. Autonomous secretion of mineralocorticoids from congenital adrenal hyperplasia.
Explanation: The clinical findings of hypertension in the upper extremities, relative hypotension in the lower extremities, and a radial-femoral pulse delay are pathognomonic for coarctation of the aorta. The narrowing of the aorta occurs distal to the left subclavian artery, leading to high pressure in the upper body and low pressure downstream. The kidneys, located downstream from the coarctation, sense this low perfusion pressure as systemic hypotension and respond by activating the RAAS, which causes systemic vasoconstriction and volume retention, further increasing the pre-coarctation blood pressure.

Question 4

A patient taking high doses of a non-steroidal anti-inflammatory drug (NSAID) for chronic arthritis develops new-onset hypertension. The patient's baseline blood pressure was normal.

The mechanism responsible for this patient's secondary hypertension involves the inhibition of which substance's synthesis?

  1. Angiotensin II, leading to a paradoxical increase in blood pressure.
  2. Aldosterone, causing compensatory sodium and water retention.
  3. Renal prostaglandins, resulting in afferent arteriolar constriction and sodium retention. (correct answer)
  4. Nitric oxide, leading to systemic vasoconstriction and endothelial dysfunction.
Explanation: NSAIDs work by inhibiting cyclooxygenase (COX) enzymes, which are necessary for the synthesis of prostaglandins. In the kidney, prostaglandins (PGE2 and PGI2) are crucial for maintaining renal blood flow, particularly in states of volume depletion or reduced effective circulating volume. They cause vasodilation of the afferent arteriole. By inhibiting prostaglandin synthesis, NSAIDs cause unopposed afferent arteriolar vasoconstriction (reducing RBF and GFR) and also directly promote sodium and water retention in the collecting ducts, both of which contribute to an increase in blood pressure.

Question 5

A 60-year-old male with a history of severe snoring, daytime sleepiness, and witnessed apneas is found to have a blood pressure of 155/95 mmHg. A sleep study confirms a diagnosis of severe obstructive sleep apnea (OSA).

Which pathophysiological sequence best explains the development of sustained hypertension in this patient?

  1. Chronic hypercapnia leads to central chemoreceptor-mediated vasodilation and reduced cardiac output.
  2. Intermittent hypoxia activates chemoreceptors, causing recurrent sympathetic nervous system surges and endothelial dysfunction. (correct answer)
  3. Recurrent arousals from sleep cause a primary increase in parasympathetic tone, leading to bradycardia and reactive hypertension.
  4. Nocturnal polyuria from increased atrial natriuretic peptide release leads to volume depletion and compensatory RAAS activation.
Explanation: In OSA, recurrent episodes of upper airway collapse cause intermittent hypoxia and hypercapnia. The hypoxia is a potent stimulus for peripheral chemoreceptors, which triggers surges in sympathetic nervous system (SNS) activity. These recurrent surges, occurring night after night, lead to a state of chronically elevated SNS tone, increased peripheral resistance, endothelial dysfunction, and inflammation, all of which contribute to the development of sustained daytime hypertension.

Question 6

A 45-year-old woman with a BMI of 32 kg/m² and a 10-year history of hypertension is described as having 'salt-sensitive' primary hypertension. She is normokalemic and has normal renal and endocrine evaluations.

Which mechanism is most likely to be a key contributor to the exacerbation of hypertension following a high-sodium meal in this patient?

  1. An exaggerated increase in aldosterone secretion in response to sodium, leading to volume retention.
  2. A blunted pressure natriuresis response, resulting in impaired renal sodium excretion and volume expansion. (correct answer)
  3. Activation of the sympathetic nervous system, causing renal afferent arteriolar constriction and renin release.
  4. Inhibition of renal prostaglandins, leading to reduced renal blood flow and increased sodium reabsorption.
Explanation: Salt sensitivity in primary hypertension is characterized by an inadequate renal response to increased sodium intake. A key mechanism is a blunted pressure natriuresis relationship, meaning that the kidneys require a higher arterial pressure to excrete a given sodium load. This leads to transient volume expansion and a sustained increase in blood pressure. The other options describe mechanisms of secondary hypertension or are incorrect responses to a sodium load (high sodium should suppress RAAS, not activate it).

Question 7

A 35-year-old woman with Grave's disease (hyperthyroidism) presents with a blood pressure of 150/75 mmHg and a heart rate of 110 bpm. She reports feeling anxious and having heat intolerance.

The primary mechanism for this patient's systolic hypertension is:

  1. Thyroid hormone-mediated increase in plasma volume through activation of the RAAS.
  2. Increased systemic vascular resistance due to thyroid hormone's direct vasoconstrictive effects.
  3. Increased myocardial contractility and heart rate, leading to a high cardiac output state. (correct answer)
  4. Deposition of mucopolysaccharides in the arterial walls, leading to decreased vascular compliance.
Explanation: Hyperthyroidism creates a hyperdynamic, high-output state. Thyroid hormone increases the sensitivity of beta-adrenergic receptors and has direct positive inotropic and chronotropic effects on the heart. This leads to increased heart rate and stroke volume, resulting in a significantly elevated cardiac output. This increased cardiac output is the primary driver of systolic hypertension. In fact, thyroid hormone typically causes peripheral vasodilation, leading to a decreased systemic vascular resistance and a wide pulse pressure.

Question 8

A 42-year-old female presents with central obesity, purple striae on her abdomen, and proximal muscle weakness. Her blood pressure is 170/105 mmHg. Laboratory tests show hyperglycemia and normal potassium levels. A dexamethasone suppression test confirms Cushing's syndrome due to a pituitary adenoma.

What is the most significant mechanism contributing to hypertension in this patient's condition?

  1. High levels of cortisol exerting mineralocorticoid effects at the kidney, causing sodium retention. (correct answer)
  2. The pituitary adenoma co-secreting aldosterone, leading to volume expansion and hypokalemia.
  3. Direct stimulation of the adrenal medulla by ACTH, causing excessive catecholamine release.
  4. Suppression of the renin-angiotensin system by high glucocorticoid levels, causing vasodilation.
Explanation: In Cushing's syndrome, the pathologically high levels of cortisol can overwhelm the enzyme (11-beta-hydroxysteroid dehydrogenase type 2) that normally inactivates it in the kidney. This allows cortisol to bind to and activate mineralocorticoid receptors, mimicking the effect of aldosterone. This leads to sodium and water retention, volume expansion, and hypertension. While other mechanisms (like increased vascular sensitivity to catecholamines) contribute, the mineralocorticoid effect of excess cortisol is a primary driver. Hypokalemia is not always present.

Question 9

A 58-year-old man with polycystic kidney disease (PKD) has progressively worsening hypertension despite being on three antihypertensive medications. His renal function is moderately impaired.

The most likely primary driver of hypertension in the early stages of this patient's disease is:

  1. Impaired sodium and water excretion due to widespread loss of functional nephrons.
  2. Production of a hypertensive substance by the cyst epithelial cells.
  3. Systemic inflammation from cyst rupture leading to generalized endothelial dysfunction.
  4. Expansion of renal cysts causing localized renal ischemia and activation of the RAAS. (correct answer)
Explanation: When you encounter a question about hypertension in polycystic kidney disease (PKD), focus on the mechanical effects of cyst expansion and timing of different pathophysiological mechanisms. In early-stage PKD, the primary mechanism driving hypertension is cyst expansion creating localized compression and ischemia. As cysts grow within the kidney parenchyma, they compress nearby blood vessels and functional tissue. This localized ischemia triggers the renin-angiotensin-aldosterone system (RAAS) as the kidney perceives decreased perfusion pressure. The juxtaglomerular cells release renin, initiating the cascade that produces angiotensin II—a potent vasoconstrictor that also stimulates aldosterone release, leading to sodium retention and hypertension. This explains why answer D is correct. Let's examine why the other options don't fit early-stage disease: A describes late-stage PKD pathophysiology when significant nephron loss has occurred, but this patient has only "moderately impaired" function. B suggests cyst epithelial cells produce hypertensive substances, but there's no established evidence for this mechanism in PKD. C proposes inflammation from cyst rupture, but spontaneous cyst rupture causing systemic inflammation isn't a primary driver of PKD hypertension, and when ruptures occur, they're typically localized events. Study tip: Remember the progression in PKD—early hypertension results from mechanical compression (RAAS activation), while late-stage hypertension involves nephron loss and impaired excretion. The timing and severity of renal impairment in the question stem will guide you toward the appropriate mechanism.

Question 10

How does the role of the sympathetic nervous system (SNS) typically differ between established primary hypertension and the hypertension seen with a pheochromocytoma?

  1. In primary hypertension, SNS overactivity is a central mechanism, whereas in pheochromocytoma, hypertension is driven by exogenous tumor-derived catecholamines. (correct answer)
  2. In primary hypertension, SNS activity is tonically elevated, whereas in pheochromocytoma, it is primarily suppressed by high circulating catecholamines.
  3. SNS activity is irrelevant in primary hypertension but is the sole cause of hypertension in pheochromocytoma.
  4. In primary hypertension, SNS outflow increases renin, whereas in pheochromocytoma, catecholamines directly inhibit renin release.
Explanation: When comparing hypertension mechanisms, you need to distinguish between the body's own dysregulated systems versus external pathological sources of vasoactive substances. In established primary hypertension, the sympathetic nervous system becomes chronically overactive as part of the body's own dysregulated cardiovascular control. This leads to increased heart rate, cardiac contractility, and peripheral vasoconstriction. The SNS overactivity also stimulates renin release, activating the renin-angiotensin-aldosterone system. Essentially, the body's own regulatory mechanisms have gone awry. Pheochromocytoma presents a fundamentally different scenario. Here, a tumor secretes massive amounts of catecholamines (epinephrine and norepinephrine) directly into circulation. These are exogenous—meaning external to normal physiological control—even though they're produced within the body. The tumor acts like an uncontrolled catecholamine factory, flooding the system with these powerful vasoconstrictors. Answer A correctly captures this distinction: primary hypertension involves the body's own sympathetic overactivity, while pheochromocytoma involves tumor-derived catecholamines. Answer B is wrong because the SNS isn't suppressed in pheochromocytoma—high catecholamines don't necessarily suppress central sympathetic outflow. Answer C incorrectly states SNS activity is irrelevant in primary hypertension, when it's actually central to the pathophysiology. Answer D focuses on renin effects, which isn't the key distinguishing feature between these conditions. Remember this pattern: primary hypertension = dysregulated body systems; secondary hypertension (like pheochromocytoma) = external pathological source overwhelming normal regulation.

Question 11

A patient with long-standing primary hypertension develops proteinuria and a modest elevation in serum creatinine. How does the pathophysiology of primary hypertension contribute to the development of this nephropathy?

  1. Systemic hypertension causes efferent arteriolar constriction, reducing glomerular filtration pressure and leading to ischemia.
  2. Increased renal perfusion from high systemic pressure leads to compensatory afferent vasodilation and glomerular hypertrophy.
  3. High systemic pressure is transmitted to the glomeruli, causing barotrauma, endothelial injury, and glomerulosclerosis. (correct answer)
  4. Chronic activation of the parasympathetic nervous system causes renal artery stenosis and subsequent parenchymal damage.
Explanation: In primary hypertension, the protective autoregulatory mechanism of the afferent arteriole can be overwhelmed. The high systemic pressure is transmitted to the delicate glomerular capillaries, causing mechanical stress (barotrauma). This leads to endothelial injury, increased permeability to proteins (proteinuria), and a chronic inflammatory and fibrotic response that results in glomerulosclerosis and a progressive decline in renal function.

Question 12

A 62-year-old male with long-standing, poorly controlled primary hypertension presents for a routine check-up. An echocardiogram demonstrates significant concentric left ventricular hypertrophy (LVH).

The development of concentric LVH in this patient is an adaptive response primarily to which hemodynamic stressor?

  1. Chronically increased pressure load (afterload) from elevated systemic vascular resistance. (correct answer)
  2. Chronically increased volume load (preload) from renal sodium retention.
  3. Direct hypertrophic stimulation of myocytes by elevated circulating angiotensin II.
  4. Increased cardiac output required to perfuse ischemic peripheral tissues.
Explanation: When you encounter cardiac hypertrophy questions, focus on distinguishing between the two main types and their underlying hemodynamic causes. Concentric hypertrophy (thickened walls, normal chamber size) develops in response to pressure overload, while eccentric hypertrophy (dilated chambers with proportionally thicker walls) results from volume overload. In poorly controlled hypertension, the left ventricle faces chronically elevated systemic vascular resistance, creating increased afterload—the pressure the heart must overcome to eject blood. This pressure overload triggers concentric hypertrophy as myocytes increase in thickness to generate more force according to Laplace's law. The heart essentially "bulks up" to handle the increased workload, similar to how skeletal muscle responds to resistance training. Choice A correctly identifies this pressure overload mechanism. Choice B describes volume overload, which would cause eccentric rather than concentric hypertrophy—you'd see this in conditions like aortic regurgitation or heart failure with fluid retention. Choice C mentions angiotensin II's direct hypertrophic effects, which do contribute to cardiac remodeling, but the primary driver of concentric LVH is the mechanical pressure overload, not direct hormonal stimulation. Choice D incorrectly suggests increased cardiac output needs, but hypertension typically involves normal or even reduced cardiac output with elevated peripheral resistance. Remember this pattern: pressure overload = concentric hypertrophy, volume overload = eccentric hypertrophy. On pathophysiology exams, they often test whether you can link the hemodynamic stress pattern to the resulting structural adaptation.

Question 13

A 38-year-old female reports episodes of severe pounding headaches, palpitations, and profuse sweating, during which her blood pressure is measured at 210/120 mmHg. Between episodes, her blood pressure is 145/90 mmHg. A 24-hour urine collection shows elevated metanephrines and normetanephrines.

The sustained hypertension observed between this patient's paroxysmal episodes is most likely mediated by which mechanism?

  1. Persistent volume expansion from mineralocorticoid effects of catecholamine precursors.
  2. Chronic upregulation and sensitization of adrenergic receptors due to intermittent catecholamine surges.
  3. Baseline continuous secretion of catecholamines from the tumor, independent of the paroxysmal surges. (correct answer)
  4. Renal ischemia induced by intense vasoconstriction during episodes, leading to chronic RAAS activation.
Explanation: The patient's symptoms and lab findings are classic for a pheochromocytoma. While these tumors are known for paroxysmal release of massive amounts of catecholamines causing hypertensive crises, many also secrete smaller amounts of catecholamines continuously. This baseline secretion is responsible for the sustained hypertension often seen in these patients between the more dramatic episodes. The other options are less likely to be the primary cause of sustained hypertension.

Question 14

A 60-year-old male with a history of severe snoring, daytime sleepiness, and witnessed apneas is found to have a blood pressure of 155/95 mmHg. A sleep study confirms a diagnosis of severe obstructive sleep apnea (OSA).

Which pathophysiological sequence best explains the development of sustained hypertension in this patient?

  1. Chronic hypercapnia leads to central chemoreceptor-mediated vasodilation and reduced cardiac output.
  2. Intermittent hypoxia activates chemoreceptors, causing recurrent sympathetic nervous system surges and endothelial dysfunction. (correct answer)
  3. Recurrent arousals from sleep cause a primary increase in parasympathetic tone, leading to bradycardia and reactive hypertension.
  4. Nocturnal polyuria from increased atrial natriuretic peptide release leads to volume depletion and compensatory RAAS activation.
Explanation: In OSA, recurrent episodes of upper airway collapse cause intermittent hypoxia and hypercapnia. The hypoxia is a potent stimulus for peripheral chemoreceptors, which triggers surges in sympathetic nervous system (SNS) activity. These recurrent surges, occurring night after night, lead to a state of chronically elevated SNS tone, increased peripheral resistance, endothelial dysfunction, and inflammation, all of which contribute to the development of sustained daytime hypertension.

Question 15

A 58-year-old man with polycystic kidney disease (PKD) has progressively worsening hypertension despite being on three antihypertensive medications. His renal function is moderately impaired.

The most likely primary driver of hypertension in the early stages of this patient's disease is:

  1. Impaired sodium and water excretion due to widespread loss of functional nephrons.
  2. Production of a hypertensive substance by the cyst epithelial cells.
  3. Systemic inflammation from cyst rupture leading to generalized endothelial dysfunction.
  4. Expansion of renal cysts causing localized renal ischemia and activation of the RAAS. (correct answer)
Explanation: When you encounter a question about hypertension in polycystic kidney disease (PKD), focus on the mechanical effects of cyst expansion and timing of different pathophysiological mechanisms. In early-stage PKD, the primary mechanism driving hypertension is cyst expansion creating localized compression and ischemia. As cysts grow within the kidney parenchyma, they compress nearby blood vessels and functional tissue. This localized ischemia triggers the renin-angiotensin-aldosterone system (RAAS) as the kidney perceives decreased perfusion pressure. The juxtaglomerular cells release renin, initiating the cascade that produces angiotensin II—a potent vasoconstrictor that also stimulates aldosterone release, leading to sodium retention and hypertension. This explains why answer D is correct. Let's examine why the other options don't fit early-stage disease: A describes late-stage PKD pathophysiology when significant nephron loss has occurred, but this patient has only "moderately impaired" function. B suggests cyst epithelial cells produce hypertensive substances, but there's no established evidence for this mechanism in PKD. C proposes inflammation from cyst rupture, but spontaneous cyst rupture causing systemic inflammation isn't a primary driver of PKD hypertension, and when ruptures occur, they're typically localized events. Study tip: Remember the progression in PKD—early hypertension results from mechanical compression (RAAS activation), while late-stage hypertension involves nephron loss and impaired excretion. The timing and severity of renal impairment in the question stem will guide you toward the appropriate mechanism.

Question 16

A patient with resistant hypertension is started on spironolactone, an aldosterone antagonist. Their blood pressure improves significantly, and their previously low serum potassium normalizes. Plasma renin activity remains suppressed.

These findings are most consistent with which underlying pathophysiologic state?

  1. Renovascular hypertension with high renin and high aldosterone levels.
  2. Primary (essential) hypertension with a high-renin profile.
  3. Primary aldosteronism with autonomous, renin-independent aldosterone secretion. (correct answer)
  4. Pheochromocytoma with catecholamine-induced activation of the RAAS.
Explanation: The dramatic response to an aldosterone antagonist (spironolactone), coupled with the history of hypokalemia and suppressed renin, points strongly to primary aldosteronism. In this condition, an adrenal source produces aldosterone autonomously, independent of the RAAS. This leads to hypertension and hypokalemia. Blocking the aldosterone receptor directly addresses the root cause. The renin level remains suppressed because the underlying volume expansion and hypertension are not corrected, they are just blocked at the receptor level, so the kidney still senses high pressure and suppresses renin release.

Question 17

A 62-year-old male with long-standing, poorly controlled primary hypertension presents for a routine check-up. An echocardiogram demonstrates significant concentric left ventricular hypertrophy (LVH).

The development of concentric LVH in this patient is an adaptive response primarily to which hemodynamic stressor?

  1. Chronically increased pressure load (afterload) from elevated systemic vascular resistance. (correct answer)
  2. Chronically increased volume load (preload) from renal sodium retention.
  3. Direct hypertrophic stimulation of myocytes by elevated circulating angiotensin II.
  4. Increased cardiac output required to perfuse ischemic peripheral tissues.
Explanation: When you encounter cardiac hypertrophy questions, focus on distinguishing between the two main types and their underlying hemodynamic causes. Concentric hypertrophy (thickened walls, normal chamber size) develops in response to pressure overload, while eccentric hypertrophy (dilated chambers with proportionally thicker walls) results from volume overload. In poorly controlled hypertension, the left ventricle faces chronically elevated systemic vascular resistance, creating increased afterload—the pressure the heart must overcome to eject blood. This pressure overload triggers concentric hypertrophy as myocytes increase in thickness to generate more force according to Laplace's law. The heart essentially "bulks up" to handle the increased workload, similar to how skeletal muscle responds to resistance training. Choice A correctly identifies this pressure overload mechanism. Choice B describes volume overload, which would cause eccentric rather than concentric hypertrophy—you'd see this in conditions like aortic regurgitation or heart failure with fluid retention. Choice C mentions angiotensin II's direct hypertrophic effects, which do contribute to cardiac remodeling, but the primary driver of concentric LVH is the mechanical pressure overload, not direct hormonal stimulation. Choice D incorrectly suggests increased cardiac output needs, but hypertension typically involves normal or even reduced cardiac output with elevated peripheral resistance. Remember this pattern: pressure overload = concentric hypertrophy, volume overload = eccentric hypertrophy. On pathophysiology exams, they often test whether you can link the hemodynamic stress pattern to the resulting structural adaptation.

Question 18

A 28-year-old male presents with a new diagnosis of hypertension (BP 165/102 mmHg). He has no family history of hypertension. Labs reveal hypokalemia (2.9 mEq/L) and a low plasma renin activity. An adrenal CT scan reveals a unilateral adrenal adenoma.

Which of the following best describes the primary pathophysiological mechanism responsible for this patient's hypertension?

  1. Excess catecholamine secretion leads to intermittent vasoconstriction and increased cardiac output.
  2. Autonomous aldosterone secretion causes sodium and water retention, leading to volume expansion. (correct answer)
  3. Renal artery stenosis causes unilateral renal ischemia, activating the renin-angiotensin system.
  4. Glucocorticoid excess enhances vascular sensitivity to catecholamines and has weak mineralocorticoid effects.
Explanation: The patient's presentation of hypertension with hypokalemia, low plasma renin, and an adrenal adenoma is classic for primary aldosteronism (Conn's syndrome). The adenoma autonomously secretes aldosterone, which acts on the kidneys to increase sodium and water reabsorption, leading to volume expansion and hypertension. The resulting high blood pressure and volume expansion suppress renin secretion from the kidneys. Hypokalemia is a direct result of aldosterone's action promoting potassium excretion.

Question 19

A 35-year-old woman with Grave's disease (hyperthyroidism) presents with a blood pressure of 150/75 mmHg and a heart rate of 110 bpm. She reports feeling anxious and having heat intolerance.

The primary mechanism for this patient's systolic hypertension is:

  1. Thyroid hormone-mediated increase in plasma volume through activation of the RAAS.
  2. Increased systemic vascular resistance due to thyroid hormone's direct vasoconstrictive effects.
  3. Increased myocardial contractility and heart rate, leading to a high cardiac output state. (correct answer)
  4. Deposition of mucopolysaccharides in the arterial walls, leading to decreased vascular compliance.
Explanation: Hyperthyroidism creates a hyperdynamic, high-output state. Thyroid hormone increases the sensitivity of beta-adrenergic receptors and has direct positive inotropic and chronotropic effects on the heart. This leads to increased heart rate and stroke volume, resulting in a significantly elevated cardiac output. This increased cardiac output is the primary driver of systolic hypertension. In fact, thyroid hormone typically causes peripheral vasodilation, leading to a decreased systemic vascular resistance and a wide pulse pressure.

Question 20

A 42-year-old female presents with central obesity, purple striae on her abdomen, and proximal muscle weakness. Her blood pressure is 170/105 mmHg. Laboratory tests show hyperglycemia and normal potassium levels. A dexamethasone suppression test confirms Cushing's syndrome due to a pituitary adenoma.

What is the most significant mechanism contributing to hypertension in this patient's condition?

  1. High levels of cortisol exerting mineralocorticoid effects at the kidney, causing sodium retention. (correct answer)
  2. The pituitary adenoma co-secreting aldosterone, leading to volume expansion and hypokalemia.
  3. Direct stimulation of the adrenal medulla by ACTH, causing excessive catecholamine release.
  4. Suppression of the renin-angiotensin system by high glucocorticoid levels, causing vasodilation.
Explanation: In Cushing's syndrome, the pathologically high levels of cortisol can overwhelm the enzyme (11-beta-hydroxysteroid dehydrogenase type 2) that normally inactivates it in the kidney. This allows cortisol to bind to and activate mineralocorticoid receptors, mimicking the effect of aldosterone. This leads to sodium and water retention, volume expansion, and hypertension. While other mechanisms (like increased vascular sensitivity to catecholamines) contribute, the mineralocorticoid effect of excess cortisol is a primary driver. Hypokalemia is not always present.