Atheroembolic Renal Disease

Cholesterol emboli are being increasingly recognized as an important cause of renal dysfunction in an aging US population. Irregularly shaped atheroemboli typically cause partial obstruction of small renal vessels resulting in ischemia. A vasculitis-like picture often evolves with an inflammatory reaction and giant cell formation. Cholesterol emboli may be temporally related to vascular manipulation, anticoagulant, or thrombolytic drug use. Spontaneous cases have been reported. Patients with cholesterol emboli may present with a spectrum of acute renal failure varying from mild and asymptomatic to life-threatening disease. The differential diagnosis includes radiocontrast nephropathy, endocarditis with left-sided emboli, vasculitis, and thrombotic emboli. The physical examination findings suggestive of cholesterol emboli include extrarenal emboli and livedo reticularis. The urinalysis is typically unremarkable. Some patients have hematuria and/or non-nephrotic proteinuria. Serology and hematology results may suggest an inflammatory-like picture with elevated erythrocyte sedimentation rate, hypocomplementemia, eosinophilia, and eosinophiluria. In the setting of a clear precipitating factor and suggestive physical findings, cholesterol emboli can be established purely on clinical grounds. Demonstration of cholesterol crystals by biopsy of the kidney, skin (if lesion present), or muscle is diagnostic in unexplained cases. The kidney is the organ most frequently involved in this order. Therapy is supportive with particular emphasis on management of hypertension and hypercholesterolemia.