Membranous nephropathy

Question 1

Membranous nephropathy: cause

Answer 1

Damage to the basement membrane causing increased permeability -> proteinuria by 3 mechanisms:

• inflammation of glomerular basement membrane
• immune complex deposition -> damaged glomerular basement membrane
• autoantibodies targeting glomerular basement membrane

Question 2

Membranous nephropathy: S

Answer 2

• often asymptomatic
• proteinuria
• Develops gradually

Question 3

Membranous nephropathy: D

Answer 3

• Light microscopy: Diffuse thickening of glomerular basement membrane
• Electron microscopy: “Spike and dome” appearance due to glomerular basement matrix on top of subepithelial deposits; effacement of podocytes
• Immunofluorescence: Deposits appear granular throughout glomerular basement membrane

If kidney biopsy not an option -> Serum: assayed for antibodies associated with membranous glomerulonephritis (anti-PLA2R antibody)

Question 4

Membranous nephropathy: T

Answer 4

Primary cause:
- For the symptomatic therapy: Diuretics (furosemide), ACE inhibitors, heparin, antibacterial drugs

• if at low risk of end-stage renal disorder (i.e. proteinuria < 3.5g/day -> Close observation, no immunosuppression
• If at moderate/high risk of end-stage renal disorde -> Prednisone + calcineurin inhibitor (e.g. tacrolimus, cyclosporine)/cytotoxic agent (e.g. cyclophosphamide)
• Rituximab

Secondary cause:
- treat the underlying condition