Membranous Nephropathy

on 2.1.09 with 0 comments



  1. Know that Membranous Nephropathy is the most common cause of NS in adults

  2. Name the causes of secondary Membranous Nephropathy

      • Drugs – penacillamine, gold, captopril

      • Infection – hepatitis B, syphilis, various parasitic diseases

      • SLE – careful to check for in young women with Membranous Nephropathy

      • Malignancy

  • Especially in lung, breast, and GI
      • Important to check for in older patients with Membranous Nephropathy

  • Sjogren’s syndrome
  • Mixed connective tissue disease
  • Systemic metabolic disorders – e.g, diabetes, thyroiditis
  • Sickle cell disease
  1. Know the Light Microscopy, Immuno Fluorescense, and Electron Microscopy findings of Membranous Nephropathy

  • LM

  • Glomeruli appear normal early in disease
  • Later, diffuse thickening of capillary walls occurs
  • Silver stain demonstrates spikes in BM between deposits
  • Trichrome stain may reveal deposits themselves
  • IF – diffuse, granular pattern of IgG and C3 deposits along subepithelial surface of capillary loops
  • EM - Electron dense deposits in subepithelial distribution with effacement of overlying foot processes

  1. Know the age, clinical manifestations and HLA antigens of patients with Membranous Nephropathy

  • Mean age of onset is 40-50
  • Most present with nephrotic syndrome (~20% with asymptomatic proteinuria)
  • Microscopic hematuria present in ~60%
  • RBC casts rare
  • HTN is uncommon
  • Renal function is usually normal
  • IC in blood is RARE – complexes are formed in situ
  • Similar to Heymann nephritis in rats linked to HLA locus caused by susceptibility to Ab to a renal auotoantigen
  1. Know how to work up a case of Membranous Nephropathy

  • Determination of antinuclear and antiDNA Ab, serum complement, rheumatoid factor, cryoglobulin, Hepatitis B Ag, VDRL, and tests to exclude diabetes

  • Older patients should have a clinical and radiologic search for occult malignancy

  • Hematuria and flank pain may indicate pulmonary emboli

  • May have other glomerular disease “ on top of ” Membranous Nephropathy

  1. Know the prognosis of Membranous Nephropathy

  • Widely variable clinical course

  • 25% -Spontaneous remission

  • 25% have persistent nephrotic range proteinuria for many years while maintaining normal renal function

  • Remaining 50% show progressive deterioration of renal function that results in end-stage renal disease in about 15 years

  • No criteria have been identified to predict which course an individual will follow

Category: Pathology Notes

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