Mesangiocapillary Glomerulonephritis

Background and Epidemiology, and Aetiology

  • Also known as membranoproliferative glomerulonephritis
  • Mainly occurs in children >5/young people
  • Characterised by a diffuse thickening and lobular appearance of the glomerular basement associated with increased cellularity
  • Can be primary (idiopathic) or secondary (more common)
    • Idiopathic can be classed as
      • Type I- subendothelial deposits of IgG/IgM and C3 (most common)
      • Type II- dense deposits of C3 in a linear fashion along the basement membrane
      • Type III- subendothelial and subepithelial deposits (usually as a result of scarring after HUS or TTP)
  • Secondary disease is usually due to
    • Autoimmune diseases e.g. SLE, Rheumatoid arthritis, Coeliac disease
    • Infections, particularly Hep B and Hep C

Pathophysiology

  • Primarily due to complement activation (resulting in decreased circulating complement)
    • Type I/Secondary MCGN is via the classical pathway and type II is via the alternative pathway
    • Type II- also many patients have autoantibodies against Nephritic factor which regulates complement and may lead to its excessive activation

Presentation

  • May be asymptomatic with proteinuria/haematuria on urinalysis
  • Proteinuria may be sufficient to cause a nephrotic syndrome
  • In some cases, patients may present with an acute nephritic syndrome (more common in children)
    • Haematuria (microscopic or gross)
    • Proteinuria
    • Hypertension
    • +/- Uraemia and oliguria
  • Other symptoms can include fat atrophy (strong association with partial lipodystrophy) which most commonly affects the upper limbs, trunk and face
    • Occasionally visual problems can occur and drusen/neovascularisation may be seen on fundoscopy
    • Both of these are associated with Type II disease (dense deposit disease- complement deficiency)

Investigations

  • See also nephrotic syndrome
  • Other tests which may be appropriate include autoantibodies (to rule out secondary causes), complement levels
  • Kidney biopsy is usually the definite test

Management

  • Treat any underlying causes
  • If primary disease, immunosuppressive agents e.g. cyclophosphamide/MMF are usually the treatment +/- steroids
  • Reduce any cardiovascular risk i.e. BP control with ACE inhibitors/ARBs

Prognosis varies between type (type II/dense deposit disease has a worse prognosis in general).  Around 50% will develop end-stage kidney disease in 10 years.

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