Question

A 57-year-old man with a history of hypertension and hyperlipidemia presents to the clinic for routine follow-up. His medications include lisinopril and atorvastatin. Despite compliance with his medications and lifestyle modifications, his blood pressure remains elevated at 158/92 mmHg on two separate visits. Laboratory tests reveal a serum potassium level of 3.1 mEq/L and a plasma aldosterone concentration that is elevated. Plasma renin activity is suppressed. A CT scan of the abdomen reveals a 1.8 cm unilateral adrenal mass.

Which of the following is the most likely underlying cause of this patient’s hypertension?

A) Pheochromocytoma

B) Renal artery stenosis

C) Primary hyperaldosteronism

D) Cushing’s syndrome

E) Liddle syndrome

Correct Answer: C) Primary hyperaldosteronism

Genetic Mutations or Sporadic Changes in Adrenal Gland
🧠 Mutations in genes (e.g., KCNJ5) → Abnormal adrenal cell growth

⬇️

Unilateral Adrenal Adenoma
🧠 Adrenal mass → Autonomous production of aldosterone

⬇️

Increased Aldosterone (↑ Aldosterone)
🧠 Effect: ↑ Sodium reabsorption (kidneys) → Water retention
🧠 Effect: ↑ Potassium excretion (kidneys) → Hypokalemia (⬇️ K⁺)

⬇️

Increased Blood Volume
🧠 Result: ↑ Blood pressure (↑ BP) → Hypertension
🧠 Result: Negative feedback to renin production → ⬇️ Plasma renin

⬇️

Clinical Findings
🧠 Hypertension → Persistent and resistant to treatment (↑ BP despite medications)
🧠 Hypokalemia → Fatigue, muscle weakness
🧠 Suppressed Renin → Confirms primary hyperaldosteronism

⬇️

CT Abdomen
🧠 Adrenal mass → Likely an aldosterone-producing adenoma (Conn's syndrome)

⬇️

Explanation of Wrong Answers

Pheochromocytoma
🧠 Causes episodic ↑ BP, sweating, headaches
🧠 Plasma renin would not be suppressed
🧠 Incorrect due to absence of catecholamine excess symptoms

⬇️

Renal Artery Stenosis
🧠 Would cause secondary hyperaldosteronism → ↑ Renin (not suppressed)
🧠 Incorrect due to suppressed renin in this patient

⬇️

Cushing’s Syndrome
🧠 Causes ↑ Cortisol → Central obesity, hyperglycemia, striae
🧠 Incorrect due to lack of cortisol excess features

⬇️

Liddle Syndrome
🧠 Causes hypertension with low renin, low aldosterone
🧠 Incorrect because aldosterone is elevated in this patient

Flashcards

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