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Acute Glomerulonephritis

Definition

  • Acute bilateral, symmetrical disease due to diffuse immune and regular inflammation of the glomeruli
  • Set of renal diseases in which an immunologic mechanism triggers inflam + proliferation of glomeruli
    • Can result in damage to the BM, mesangium or capillary endothelium
  • Not an infectious disease, however >90% cases occur post-strep infection – MC in 5-15yo

Etiology

Classification of GLN

1o GN – glomeruli involved 2o GN – systemic diseases
  • Acute GN
  • Lupus nephritis
  • Chronic GN
  • DM nephropathy
  • Rapidly progressive
  • Amyloidosis
  • Minimal change
  • Wegener’s disease
  • Membranous
  • Good pasture’s
  • IgA Nephropathy
  • Post URT inf (post strep) – β-hem gp A strep
    • Type 12 most nephritogenic
    • Others – 4,6,14,19,25
    • Enter via nasopharynx/skin
  • Other infectious agents
    • Bacteria – staph, pneumo + meningio -coccus, rickettsia
    • Virus – mumps, hepatitis, small pox

Pathogenesis

  • Immune complex disease triggers inflammation + proliferation of glomeruli
    • Damage to BM, mesangium, capillary endothelium
  • Glomerular lesions are the result of deposition of immune complexes, components of ICs
    • Ag/bacterial protein/endotoxin
    • Ab – IgG
    • Complement – C3
  • Two types of immune complexes
    • In circulation ( CIC )
    • In renal capsule ( In situ )
  • Acute Nephritic syndrome is most serious of the renal syndromes
    • Edema, mild proteinuria, haematuria
  • Macroscopically – kidneys symmetrically enlarged, petechiae on surface ( flea-bitten kidney  )
  • Microscopically – 2 periods
    • Exudative period – glomeruli hyperaemia
      • Cells present – RBC, WBC, monocytic infiltration
    • Proliferative period – structural, cellular proliferation, increase no of cells
      • Proliferation of mesangium and endothelium – mesangioproliferative type GN
      • Granular staining of IgG, C3, fibrin by immunofluorescence

Clinical features

USG

  • Normal – 1.010-1.040
  • Isosthenuria – 1.010
  • Sudden onset, seasonal (mid autumn, mid spring)
  • Triad of Volhard
    • Edema – face, periorbital
    • HTN – not severe, 160/90
    • Hematuria – mac/microscopic
  • Urinary symptoms

Proteinuria

  • Mild – 1.5-4g/L
  • Severe – >4g/L
    • Proteinuria – mild (0.5-2g/l)
    • Polyuria – >2L/day
    • Sediment – hematuria
    • Increased USG
  • HTN + CV symp – due to retention of salt and water
  • Neurologic symptoms – brain oedema
  • Renal function
    • Decreased GF – decreased clearance, brief azotemia
    • Normal tubular function and renal plasma flow rate – increased USG
    • Decreased filtration fraction – GFR/RPF

Diagnosis

  • History – previous throat inf, prior kidney disease
  • Blood – high WBC, low RBC
  • Immunologic tests – high AST, low comp, high CIC

Treatment

  • Penicillin – 3-4 mil IU/24hrs
    • 10-14days
  • Ampicillin – 3-4g/24hr
  • Special case – erythromycin, cephalosporins
  • Prophylaxis – benzacillin 200,000 IU
  • Pathogenetic tx
    • Calcium gluconate – 10% 10ml BD
    • Vit C – 500mg BD
  • Symptomatic treatment
    • Diuretics, anti-HTN, treat cardiac failure , brain oedema
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