[Case of purpura nephritis accompanied by idiopathic cholesterol embolism].

A 69-year-old man with a history of hypertension was admitted to our hospital because of proteinuria, renal dysfunction, and both purpura and edema in the lower extremities. Laboratory data on admission revealed proteinuria (3.4 g/day), microscopic hematuria (3+), and renal dysfunction (serum creatinine 1.47 mg/dL). In the renal biopsy, all glomeruli showed mild mesangial proliferation. A few glomeruli showed mild segmental endocapillary proliferation. Crescent was not found in any glomeruli. Immunofluorescent study revealed the deposition of IgA and C3 in the mesangial area. In addition, jagged-edged angular cholesterol clefts of atheromatous emboli were seen in a small artery with tubular atrophy and fibrosis. He was diagnosed as Henoch-Schonlein purpura nephritis accompanied by idiopathic cholesterol crystal embolism, because he previously had not undergone any cardiac procedures (e. g., percutaneous coronary intervention and coronary artery bypass grafting) and anticoagulating therapy. Oral prednisolone (40 mg/day) effectively decreased proteinuria and improved his renal dysfunction. In this case, renal dysfunction may be related to the ischemic interstitial damage caused by cholesterol crystal embolism, as well as purpura nephritis.