Fogo, Ch. 2 - Membranous Nephropathy

Question 1

What causes are associated with secondary membranous nephropathy?

Answer 1

Hepatitis B virus, Sjogren’s, SLE, Syphilis, drugs & heavy metals

Question 2

Describe the glomerular phenotype of membranous nephropathy.

Answer 2

Thickened capillary wall with irregular GBM thickening (“spikes”). No mesangial disease or inflammatory infiltrate. Can have sclerosis but not necrosis or crescents.

Question 3

Describe the tubulointerstitial phenotype in membranous nephropathy.

Answer 3

Tubules have protein reabsorption droplets. Interstitial foam cells and later fibrosis.

Question 4

Describe the IF findings in membranous nephropathy.

Answer 4

Fine granular (almost linear) deposits usually of IgG/C3.

Question 5

Describe the EM findings in membranous nephropathy.

Answer 5

Subepithelial deposits in the glomerular capillary wall and GBM spikes (later thickening & deformation). Podocyte foot effacement can be present.

Question 6

What entities are associated with primary/autoimmune membranous nephropathy?

Answer 6

Mutations in endopeptidase, IgG4 M-type PLA2R, dairy bovine albumin?

Question 7

How many cases of membranous nephropathy are obviously secondary?

Answer 7

10-25%

Question 8

How is membranous nephropathy clinically managed?

Answer 8

Steroids/immunosuppression and anti-angiotensin therapy.

Question 9

How common is membranous nephropathy?

Answer 9

It is the #1 cause of nephrotic syndrome in adults (30-50% of cases)

Question 10

What are the four ultrastructural stages of membranous nephropathy?

Answer 10

I: Subepithelial deposits with normal GBM

II: Subepithelial deposits with GBM spikes

III: Intramembranous deposits of variable electron density

IV: Irregularly thickened GBM without electron-dense deposits