Nephrotic Syndromes

Question 1

Focal Segmental Glomerulosclerosis

Answer 1

LM - segmental sclerosis and hyalinosis
IF - focal deposits IgM, C3, C1 (typically negative IF)
EM - effacement of foot processes

• Idiopathic or Secondary (HIV, SSC, heroin, massive obesity, IFN Tx, congenital malformation CKD)
• Poor response to steroids
• Most common cause of nephrotic syndrome in Af. Am. and Hispanics

Question 2

Minimal Change Disease (lipoid nephrosis)

Answer 2

LM - normal (possible lipids in PCT cells)
IF - negative
EM - effacement (fusion) of foot processes

• Idiopathic or Secondary (infection, vaccination, allergic rxn (bee sting); rarely cytokine mediated via Hodgkins lymphoma)
• Selective proteinuria (albuminuria only)
• Responds to corticosteroids or becomes FSGS

Question 3

Membranous Nephropathy

Answer 3

LM - diffuse capillary and GBM thickening
IF - granular (IC deposition)
EM - Subepithelial deposits; “Spike and dome”

• Idiopathic or Secondary (PLA2-R Ab’s, drugs [NSAIDs, penicillamine], infections [HBV, HCV], SLE, solid tumors
• Nephrotic presentation of SLE
• Most common primary nephrotic syndrome of white adults
• Poor steroid response

Question 4

Amyloidosis

Answer 4

LM - congo red stain shows apple-green bifring under polarized light

• Assoc. with chronic conditions (MM, TB, RA)
• Tamm-Horsfall proteins + bence jones (Tm maxed) form eosinophilic casts causing obstruction

Question 5

Diabetic Glomerulonephropathy (nodular glomerulosclerosis)

Answer 5

LM - mesangial expansion (NE-glycosylation of eff. art. (hyaline arteriolosclerosis) causing increased GFR [hyperfiltration injury], GBM thickening (NE-glycosylation of GBM increases permeability), Kimmelstiel-Wilson lesions

• Rx. ACEI
• Associated w/ increased heparinase from renal epithelial cells