Glomerulonephritis, Infection-related & Postinfectious

Key Features

• Infection-related glomerulonephritis are entities resulting in glomerular injury during active infection

• Postinfectious glomerulonephritis commonly appears after pharyngitis or impetigo with onset 1–3 weeks after infection (average 7–10 days)

• Bacterial causes

  • Bacteremic states (especially with Staphylococcus aureus)

  • Bacterial pneumonias

  • Deep-seated abscesses

  • Gram-negative infections

  • Infective endocarditis

  • Shunt infections

• Viral, fungal, and parasitic causes

  • Hepatitis B or C

  • HIV

  • Cytomegalovirus infection

  • Infectious mononucleosis

  • Coccidioidomycosis

  • Malaria

  • Mycobacteria

  • Syphilis

  • Toxoplasmosis

Clinical Findings

• Disease presentation can vary widely across the nephritic spectrum from asymptomatic glomerular hematuria (especially in epidemic cases) with minimal change in kidney function, to nephritic syndrome with hypertension, edema, and perhaps gross glomerular hematuria (smoky-colored urine)

• The most severe cases may result in oliguric AKI requiring dialysis

Diagnosis

• Serum complement levels are low

• Antistreptolysin O (ASO) titers sometimes high

• 24-h urine protein < 3.5 g/day

• Kidney biopsy

  • Light microscopy shows diffuse proliferative glomerulonephritis

  • Immunofluorescence demonstrates granular deposition of IgG and C3 in the mesangium and along the capillary basement membrane

  • Electron microscopy shows large, dense subepithelial deposits or "humps"

Treatment

• Supportive measures

• Antibiotics, as indicated for infection

• Antihypertensive medications

• Salt restriction

• Diuretics

• Corticosteroids have been tried in severe cases but have not been shown to improve outcomes