Rapidly progressive glomerulonephritis associated with bacterial endocarditis: efficacy of antibiotic therapy alone

A 65-year-old woman presented rapidly progressive glomerulonephritis with purpura and mitral insufficiency. Blood cultures grew Streptococcus mitis. By light microscopy, the renal biopsy revealed necrotizing glomerulonephritis 56% associated with cellular crescents and tubulointerstitial changes. By immunofluorescence, deposits of IgM and C3 were found to be present in the mesangium. Electron-microscopic study showed subendothelial and intramembranous deposits. Treatment with antibiotics alone resulted in renal recovery with disappearance of proteinuria, circulating immune complexes and cryoglobulinemia. A 2nd renal biopsy, performed after 3 months, showed segmental sclerosis and tubulointerstitial lesions. Eight months after the first hospitalization, cardiac insufficiency occurred. Four years later, a valve replacement was performed. No abnormal serum creatinine, serum creatinine clearance or urinalysis levels were present. These data suggest that rapidly progressive glomerulonephritis associated with bacterial endocarditis may be treated by antibiotics alone and result in normal and stable renal function.