Diagnostic features:
(1) evidence of a previous streptococcal infection, which may have been subclinical
(2) clinical and laboratory evidence of a renal disease
(3) changes seen on renal biopsy (if performed)
Evidence of a previous streptococcal infection:
(1) pharyngitis or pyoderma
(2) serum anti-streptolysin (ASO) antibody titi > 250 IU/mL
(3) serum anti-DNAse B > 200 IU/mL
(4) positive culture for Strepotoccus pyogenes
(5) low serum C3 concentration (hypocomplementemia)
Clinical and laboratory evidence of renal disease:
(1) hematuria (gross or > 10 RBCs per µL unspun urine)
(2) new-onset or worsening of hypertension
(3) facial or peripheral edema
(4) proteinuria
Renal biopsy (often not performed) will show:
(1) variable histologic findings, the most common being diffuse proliferative glomerulonephritis with glomerular capillary neutrophils
(2) dense deposits on electron microscopy (mesangial, subendothelial, subepithelial)
(3) immunofluorescence positive for for C3, with variable deposition of IgG, IgM and IgA
