Acute Postinfectious Glomerulonephritis

Module : Urinary System


Definition:  

Acute postinfectious GN, one of the more frequently occuring glomerular disorders, 

typically caused by glomerular deposition of immune complexes resulting in diffuse

proliferation and swelling of resident glomerular cells and frequent infiltration of

leukocytes, especially neutrophils.

 Initial infection is localized to the pharynx or skin.

Morphology: 

Light microcopy : 

• uniformly increased cellularity of the glomerular tufts
• subepithelial "humps" nestled against the GBM (Glomerular Basement Membrane)
• scattered granular deposits of IgG and complement within the capillary walls.

Pathogenesis : 

• immune complex deposition is involved.
• typical features: hypocomplementia and granular deposition of IgG and complement on the     GBM.
• relevant antigens are probably streptococcal proteins.
• unclear whether immune complexes are formed mainly in circulation or in situ.
• C3 deposited on the GBM before IgG, the primary injury might be by complement activation. Thus, immune complexes are formed.

*hypocomplementia - diminution of complement levels in blood.