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A 38-year-old woman presented to her local clinic for recurrent episodes of headache of several weeks' duration. Evaluation revealed a blood pressure of 202/136 mm Hg. The patient was prescribed 37.5 mg of triamterene with 25 mg of hydrochlorothiazide (1 tablet) twice daily and 50 mg of atenolol once daily.
Her blood pressure remained elevated, and her headaches persisted. She was referred to the hypertension clinic for further management.
The patient's medical history was remarkable for preeclampsia during her second pregnancy 9 years previously. She smoked half a pack of cigarettes per day for 15 years. Her alcohol use was limited to social gatherings and consisted of 1 to 2 drinks monthly. She exercised regularly and had a balanced low-salt diet. Essential hypertension was common on her maternal side.
On physical examination, the patient's blood pressure was 172/100 mm Hg (both arms), and her heart rate was 90 beats/min. Findings on funduscopic examination were normal. Cardiac examination revealed a grade 2/6 systolic ejection murmur at the right upper sternal border. Abdominal examination was remarkable for a systolic-diastolic bruit present over the right midabdomen without palpable masses. No evidence of pitting edema was observed, and findings on lung examination were normal.
Initial work-up included the following (reference ranges shown parenthetically): hemoglobin, 14.1 g/dL (12.0-15.5 g/dL); creatinine, 0.8 mg/dL (0.7-1.2 mg/dL); sodium, 139 mEq/L (135-145 mEq/L); potassium, 4.2 mmol/L (3.6-4.8 mmol/L); bicarbonate, 29 mEq/L (22-29 mEq/L), and calcium, 9.5 mg/dL (8.9-10.1 mg/dL). Findings on electrocardiography were normal.
Our case highlights several important clinical pearls. First, FMD is prevalent in women with a history of smoking8 and predominantly affects the mid-to-distal portions of renal arteries. In contrast, atherosclerotic lesions are typically ostial, occur in elderly patients with a history of cardiovascular risk factors, and require aggressive management of risk factors even after successful revascularization. As for the diagnosis, noninvasive testing is widely accepted as the first step, with renal angiography frequently being limited to those with positive findings on preliminary studies, despite the fact that the diagnostic accuracy of commonly used tests varies widely.4 With respect to treatment, pharmacologic management with either an ACEI or an angiotensin II receptor blocker is the first line of treatment. Because of the risk of teratogenicity, these agents should not be used in patients of child-bearing age who desire to become pregnant. Previous studies have reported poor pregnancy outcomes in women with renovascular hypertension; however, both maternal and fetal outcomes improved in subsequent pregnancies after either revascularization or excision of the small, poorly functioning kidney.9 Revascularization is also often offered to patients with an increased likelihood of cure, such as those who are young and have recent-onset hypertension.10 Serious complications, such as renal artery dissection, may occur on rare occasions, and 17% to 25% of patients are at risk of developing restenosis within 6 months of the procedure. Judicious use of follow-up imaging studies, coupled with close blood pressure monitoring, may facilitate timely recognition and treatment of both early complications and unfavorable clinical outcomes.11 Finally, for highly selected patients with small, atrophic kidneys and resistant hypertension, unilateral nephrectomy (of the atrophic kidney) may improve blood pressure control without adverse effects on renal function. Blood pressure improved in 78% of patients whose “pressor” kidney was removed.12
Renal artery stenosis secondary to FMD is the second most common cause of renovascular hypertension after atherosclerotic renal artery stenosis. Factors that should prompt clinical suspicion of renal FMD include young age, female sex, history of smoking, no family history of essential hypertension, and an abdominal bruit. Management includes medical therapy, revascularization, and, in rare cases, unilateral nephrectomy. Patient prognosis is generally good, but annual renal imaging studies are crucial in monitoring the long-term effects of FMD on renal artery patency and kidney size.
See end of article for correct answers to questions.
Correct answers: 1. d, 2. c, 3. b, 4. a, 5. d