A 23-year-old woman with no other medical history was diagnosed with hypertension 6 months ago. She was initially treated with hydrochlorothiazide, followed by the addition of lisinopril, followed by a calcium channel blocker, but her blood pressure has not been well controlled. She assures the provider that she is taking all of her medicines. On examination her blood pressure is 165/105 in each arm, and 168/105 when checked by large cuff in the lower extremities. Her pulse is 60. Cardiac examination reveals an S4 gallop but no murmurs. She has a soft mid-abdominal bruit. Distal pulses are intact and equal. She does not have hyperpigmentation, hirsutism, genital abnormalities, or unusual distribution of fat. Her sodium is 140, potassium 4.0, HCO3 22, BUN 15, and creatinine 1.5. Which of the following is the most likely cause of her difficult-to-control hypertension?
A 23-year-old woman with no other medical history was diagnosed with hypertension 6 months ago. She was initially treated with hydrochlorothiazide, followed by the addition of lisinopril, followed by a calcium channel blocker, but her blood pressure has not been well controlled. She assures the provider that she is taking all of her medicines. On examination her blood pressure is 165/105 in each arm, and 168/105 when checked by large cuff in the lower extremities. Her pulse is 60. Cardiac examination reveals an S4 gallop but no murmurs. She has a soft mid-abdominal bruit. Distal pulses are intact and equal. She does not have hyperpigmentation, hirsutism, genital abnormalities, or unusual distribution of fat. Her sodium is 140, potassium 4.0, HCO3 22, BUN 15, and creatinine 1.5. Which of the following is the most likely cause of her difficult-to-control hypertension?
💡 Explanation
**Core Concept**
The underlying principle being tested is the diagnosis of secondary hypertension, specifically focusing on **renal artery stenosis** as a cause of resistant hypertension. This condition involves the narrowing of the renal arteries, leading to decreased blood flow to the kidneys.
**Why the Correct Answer is Right**
The presence of a **mid-abdominal bruit**, which is a murmur heard over the abdomen, is suggestive of renal artery stenosis. This condition activates the **renin-angiotensin-aldosterone system (RAAS)**, leading to increased blood pressure. The patient's lack of response to multiple antihypertensive agents, including an **ACE inhibitor (lisinopril)**, which would typically be effective in RAAS-mediated hypertension, and the presence of a bruit, point towards a vascular cause of her hypertension.
**Why Each Wrong Option is Incorrect**
**Option A:** Would be incorrect as there's no indication of hyperaldosteronism (e.g., hypokalemia).
**Option B:** Incorrect due to the absence of symptoms or signs suggestive of pheochromocytoma (e.g., episodic hypertension, tachycardia).
**Option C:** Not supported due to the lack of clinical features of Cushing's syndrome (e.g., hyperpigmentation, hirsutism).
**Clinical Pearl / High-Yield Fact**
A key point to remember is that the presence of a **bruit** over the abdomen in a patient with hypertension should prompt an investigation for renal artery stenosis, particularly if the hypertension is resistant to conventional treatment.
**Correct Answer:** D. Renal artery stenosis.
✓ Correct Answer: D. Renal artery fibromuscular dysplasia
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