A 26-year-old woman dies shortly after a sudden-onset, severe headache. She was recently diagnosed with hypertension but otherwise had no medical problems. The patient was a lifetime nonsmoker and did not use illicit drugs. Autopsy reveals evidence of intracranial hemorrhage. Both carotid arteries appear tortuous distally with alternating areas of fibrotic webs and aneurysmal dilation. On microscopic examination, the aneurysmal segments of the carotid arteries lack an internal elastic lamina. Which of the following is the most likely additional finding in this patient?
Fibromuscular dysplasia | |
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RAS = renal artery stenosis; TIA = transient ischemic attack. | |
This young woman with recent-onset hypertension died of an intracranial hemorrhage, likely from a ruptured aneurysm. This, in conjunction with the characteristic pathology findings of fibromuscular webs alternating with aneurysmal dilation and loss of the internal elastic lamina, is consistent with fibromuscular dysplasia (FMD). FMD is a nonatherosclerotic disease characterized by abnormal tissue growth within arterial walls, leading to arterial stenosis, tortuosity, aneurysms, or dissections. FMD typically occurs in women age <55. Angiography (ie, percutaneous, CT, MRI) is diagnostic and typically demonstrates a string-of-beads appearance in multifocal disease.
FMD can involve any artery but most commonly the renal, cerebral (eg, carotid, vertebral), and visceral arteries. Up to 80% of patients develop renal artery stenosis, which limits renal perfusion and leads to activation of the renin-angiotensin-aldosterone system. The resultant hypertension is often the earliest sign of the disease. Other presentations are related to locations of the dysplastic artery; cerebrovascular involvement (ie, headache, stroke, aneurysm rupture), mesenteric ischemia, or extremity claudication may be seen.
(Choices A and B) Adrenal tumors that can present with severe hypertension include pheochromocytoma and aldosterone- or cortisol-secreting adrenocortical adenomas. Coarctation of the aorta also causes hypertension, with blood pressure higher in the upper versus lower extremities. Due to the elevated blood pressure, these diseases can cause headaches and intraparenchymal hemorrhage in predisposed individuals, but they are not associated with fibrotic webbing or aneurysm formation.
(Choice C) Hypertrophic cardiomyopathy may present with sudden death in young patients due to left ventricular outflow obstruction; histology demonstrates hypertrophied myocytes and interstitial fibrosis. However, hypertrophic cardiomyopathy is not associated with aneurysm formation.
(Choice E) Thyroid follicular hyperplasia can cause hyperthyroidism (eg, Graves disease, thyroid adenoma). This commonly causes tachycardia, tremor, and palpitations but would not cause aneurysm formation.
Educational objective:
Fibromuscular dysplasia is characterized by abnormal tissue growth within arterial walls, resulting in stenotic and tortuous arteries that can cause tissue ischemia and are prone to aneurysm formation. Pathology typically demonstrates alternating fibromuscular webs and aneurysmal dilation with absent internal elastic lamina (string-of-beads appearance). Renovascular hypertension occurs due to renal artery stenosis and activation of the renin-angiotensin-aldosterone system.