Pathology - ​Poststreptococcal Glomerulonephritis (Acute Proliferative Glomerulonephritis)

Pathology - ​Poststreptococcal Glomerulonephritis (Acute Proliferative Glomerulonephritis)
Commonly observed in youngsters after being infected with nephritogenic strains of group A beta-hemolytic streptococci.

Study of diseases 
The gross pathology shows a severe inflammatory response affecting all glomeruli in both kidneys, leading to pinpoint hemorrhages on the surfaces of the kidneys.
Under light microscopy, the glomeruli seem enlarged, hypercellular, and swollen with increased mesangial and endothelial cell proliferation. The thickness of the glomerular basement membrane is within normal range.
Electron microscopy reveals electron-dense humps located on the epithelial side of the basement membrane (subepithelial localization).
Immunofluorescence shows a coarse granular pattern for lgG or C3 (lumpy-bumpy).

Clinical Symptoms 
Nephritic syndrome presenting with hypertension and swelling around the eyes.
Laboratory results show presence of red blood cells and/or red cell casts in urine, low levels of serum C3, high ASO antibody titer indicating recent streptococcal infection, and azotemia.

Treatment typically results in spontaneous resolution.

Poststreptococcal glomerulonephritis is an immunological complex disease characterized by antigen-antibody complexes of streptococcal origin. It is considered the classic example of the nephritic syndrome.