Glomerulonephritis

Basics

Description

  • Glomerulonephritis presents with the nephritic syndrome: hematuria with RBC casts, hypertension, variable azotemia, and edema. Proteinuria and oliguria may also be present.
  • Acute glomerulonephritis is associated with inflammation and cell proliferation in the glomerular tuft. It may be rapidly progressive.
  • Chronic glomerulonephritis indicates permanent damage has occurred.

Epidemiology

  • Postinfectious glomerulonephritis can occur after any infection; ~80% of cases are secondary to a streptococcal infection.
  • Acute poststreptococcal glomerulonephritis (APSGN) can occur in anyone >2 years but is most frequently found in boys 5 to 15 years old. It can be sporadic or epidemic.
  • Incidence of APSGN has declined over the last 2 decades.
  • Chronic glomerulonephritis occurs more often at the end of the 1st decade of life and in adults.

Risk Factors

Exposure to nephritogenic streptococci

Genetics

Genetic predisposition: hereditary nephritis (e.g., X-linked Alport syndrome); C3 glomerulopathy, atypical HUS (complement regulation disorders)

Etiology

Can be categorized based on serum complement levels and presence of renal-limited versus systemic disease

  • Low serum complement level: systemic diseases
    • Vasculitis and autoimmune disease (e.g., systemic lupus erythematosus [SLE])
    • Subacute bacterial endocarditis (SBE)
    • Shunt nephritis
    • Cryoglobulinemia
  • Low serum complement level: renal diseases
    • APSGN
    • Membranoproliferative glomerulonephritis, C3 glomerulopathy
  • Normal serum complement level: systemic diseases
    • Microscopic polyangiitis (MPA)
    • Granulomatosis with polyangiitis (GPA)
    • Henoch-Schönlein purpura (HSP)
    • Hypersensitivity vasculitis
    • Anti-GBM disease (Goodpasture syndrome)
  • Normal serum complement level: renal diseases
    • IgA nephropathy
    • Idiopathic rapidly progressive glomerulonephritis
    • Pauci-immune glomerulonephritis (renal-limited ANCA vasculitis)
    • Immune-complex disease

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