The glomeruli in post-infectious glomerulonephritis show diffuse mesangial proliferation and endocapillary proliferation accompanied by infiltration of neutrophils and mononuclear inflammatory cells. Crescents may also be present . Immunofluorescence microscopy demonstrates granular deposits of C3 and IgG along the capillary loops and in the mesangium. The capillary loop deposits become less frequent after a few weeks, but the mesangial deposits persist for a longer period. Ultrastructurally large subepithelial deposits are present which are usually scattered along the basement membrane.
Mesangial deposits are also present.
The onset is usually abrupt, with a latent period of 7 to 21 days beteen infection and the development of nephritis. Asymptomatic contacts may have hematuria. In most patients hematuria disappears by 6 months but proteinuria may persist for two years in a third of patients. Early antimicrobial therapy in affected individuals and family members may prevent the spread of streptococcal infections. Treatment of established infection does not prevent the development of post-streptococcal glomerulonephritis, but may lessen its severity.