A Case of Steroid-responsive C1q Nephropathy Presenting as Focal Segmental Glomerulosclerosis / 대한신장학회지

ABSTRACT

C1q nephropathy is an immune complex glomerulonephritis defined by the presence of mesangial immunoglobins and complement deposits, most notably C1q, and the absence of clinical and laboratory evidence of systemic lupus erythematosus. Most patients with C1q nephropathy present nephrotic-range proteinuria, which has a poor response to steroid. Some patients may experience decreased renal function and progress to end stage renal disease. A 27year-old man presented with proteinuria and decreased mental state. The patient was hypertensive, with a blood pressure of 180/120 mmHg. Serum BUN/creatine was 18/1.8 mg/dL, and urinalysis revealed proteinuria (3+). Brain computed tomography showed right basal ganglial and intraventricular hemorrhage. The patient was treated with craniotomy and hematoma removal, and he also received carvedilol, losartan, nifedipine, and doxazosin for control of BP. Although his mental status recovered and blood pressure was controlled, the patient still showed subnephrotic proteinuria; therefore, renal biopsy was performed. Kidney biopsy showed segmental sclerosis in 3 out of 14 glomeruli, and mesangial C1q immunofluorescence positive staining. Electron microscopic findings revealed electron-dense deposits in the mesangium. The patient was treated with oral prednisolone, and proteinuria was alleviated after 8 weeks and remains in complete remission.