Fibromuscular dysplasia

A previously healthy 46-year-old African-American man presented to an outside hospital with several weeks of fever, 20 lb weight loss in the previous month, and left flank pain. He was hypertensive, urinalysis was notable for the absence of protein, blood, and cellular elements, and the erythrocyte sedimentation rate was minimally elevated at 23mm/h. His family history was relevant for uncomplicated hypertension in both parents. CT scan with intravenous contrast demonstrated bilateral renal infarctions, and serum creatinine rose from 1.2 to 1.7mg/dl shortly after admission. Renal angiography revealed stenoses in both main renal arteries, as well as in first- and second-order branches of the vasculature to the right upper pole. Aneurysmal dilatations were present in the upper pole branches and at the left hilum. Given the radiographical findings and systemic complaints, the patient was diagnosed with polyarteritis nodosa (PAN) and initiated on steroid therapy. One week after discharge, the patient complained of chest pain in the setting of persistent flank pain, and his serum creatinine had risen to 2.3mg/dl. He was readmitted to the hospital, myocardial infarction was excluded, and he was transferred to the Johns Hopkins Hospital for further evaluation. On transfer, the patient was taking prednisone 80mg/day, lisinopril 20mg/day, amlodipine, and atenolol. On physical examination, he was afebrile, blood pressure 135/77 mm Hg, pulse 64/min, and respirations 20/min. Physical findings were significant for normal pulmonary and cardiovascular examinations and the presence of costovertebral angle tenderness bilaterally. Laboratory studies on admission (Table 1) were notable for mild-to-moderate renal dysfunction with mild anemia and normal markers of inflammation. Urinalysis was unrevealing, and proteinuria was estimated at 0.22 gProtein/gCreatinine on a spot urine sample. In an attempt to confirm the diagnosis of PAN, the patient underwent testicular ultrasound and mesenteric angiography, both of which were normal. Selective renal angiography was then performed with intravascular ultrasound (IVUS). Angiography demonstrated a tight left mid-renal artery narrowing (Figure 1) with focal areas of infarction throughout the renal parenchyma (Figure 2). This stenosis had mildly worsened since the initial studies, and IVUS demonstrated the presence of a focal dissection flap (Figure 3). In addition, moderate improvement since the prior study was seen in both the stenosis of the right upper pole arterial branch and the associated aneurysm.