A 25-year-old woman comes to the physician complaining of transient vision loss in the right eye. Six months ago, she was told that her blood pressure was high at a local health fair. Her past medical history is otherwise unremarkable and she takes no medications. Her grandmother had a stroke at age 50. Her blood pressure is 164/103 mm Hg and pulse is 77/min. Her body mass index is 26 kg/m². Examination shows a bruit below the right mandibular angle. Chest and abdominal examinations are unremarkable. She has 2+ lower extremity pulses. Laboratory results are as follows: Which of the following is the best next step in management of this patient?

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11ec25c8_d366_d054_bc81_136509af8e8c_MD0003_00 This patient's transient monocular vision loss is consistent with amaurosis fugax. Monocular vision loss is usually due to disorders anterior to the optic chiasm (eg, optic nerve). Emboli from severe ipsilateral carotid stenosis can cause ischemia of the optic nerve and transient vision loss. This younger woman's significantly elevated blood pressure also raises suspicion for a secondary cause of hypertension. Her transient vision loss, family history of stroke, and carotid bruit suggest fibromuscular dysplasia (FMD). FMD most commonly affects women age 15-50. It is a noninflammatory and nonatherosclerotic condition caused by abnormal cell development in the arterial wall that can lead to vessel stenosis, aneurysm, or dissection. FMD can involve any artery but most commonly involves the renal, carotid, and vertebral arteries. Patients with renal artery involvement usually develop hypertension. Involvement of cerebrovascular arteries (eg, carotid, vertebral) can lead to nonspecific symptoms (eg, headache, pulsatile tinnitus, dizziness) or symptoms of brain ischemia (eg, transient ischemic attack, stroke, amaurosis fugax). FMD can also involve the iliac, subclavian, and visceral arteries. Diagnosis is usually confirmed with noninvasive imaging (computed tomography angiography of the abdomen or duplex ultrasound). Patients with inconclusive noninvasive tests require catheter-based digital subtraction arteriography for diagnosis. FMD decreases perfusion to the kidneys, which increases both renin and aldosterone levels (secondary hyperaldosteronism). The aldosterone concentration to renin activity ratio is ~10 (<20). (Choice A) Adrenal vein sampling can differentiate between adrenal hyperplasia and adenoma, which are causes of primary hyperaldosteronism. Although these patients can also develop hypertension and hypokalemia, the plasma aldosterone is >15 ng/dL and suppresses the renin through a feedback inhibition. As a result, the plasma aldosterone concentration/plasma renin activity ratio is >20. (Choice C) Dexamethasone suppression test can diagnose Cushing's syndrome. Patients typically develop findings such as central obesity, purple striae, proximal muscle wasting, glucose intolerance, and hypertension. (Choice D) Erythrocyte sedimentation rate is typically elevated in a large-vessel vasculitic process such as giant cell arteritis (GCA). GCA can present with systemic symptoms (eg, fever, fatigue), headache, visual symptoms (eg, transient monocular vision loss), and jaw claudication. GCA can be associated with a carotid bruit, but it is very uncommon in patients age <50 and usually does not cause significant hypertension. (Choice E) Plasma free metanephrines would be elevated in pheochromocytoma, which is a secondary cause of hypertension. Patients usually develop hypertension and the classic triad of episodic headache, sweating, and palpitations with tachycardia. Educational objective: Fibromuscular dysplasia is a noninflammatory and nonatherosclerotic condition that presents most commonly in women age 15-50. The condition affects primarily the renal arteries and causes hypertension. Involvement of the cerebrovascular arteries (eg, carotid, vertebral) can cause symptoms of brain ischemia (eg, transient ischemic attack, amaurosis fugax, stroke) or nonspecific symptoms (eg, headache, pulsatile tinnitus, dizziness). References: Contemporary management of fibromuscular dysplasia. (http://www.ncbi.nlm.nih.gov/pubmed/18830066)

A 25-Year-Old Woman Comes to the Physician Complaining of Transient