Nephrotic Syndrome

Question 1

Focal segmental glomerulosclerosis

Answer 1

Light microscopy: segmental sclerosis and hyalinosis

Electron microscopy: effacement of foot processes similar to minimal change disease

Most common cause of nephrotic syndrome in adults.

Associated with HIV infection, heroin abuse, massive obesity, interferon treatment, and chronic kidney disease due to congenital absence or surgical removal

Question 2

Membranous nephropathy

Answer 2

Light microscopy: diffuse capillary and GBM thickening

Electron microscopy: spike and dome appearance with sub epithelial deposits

IF: granular. SLE’s nephrotic presentation. Second most common cause of primary nephrotic syndrome in adults. Can be idiopathic or causes by drugs, infections, SLE, solid tumors.

Question 3

Minimal change disease (lipoid nephrosis)

Answer 3

Light microscopy: normal glomeruli

Electron microscopy: foot process effacement

Selective loss of albumin, not globulins, caused by GBM polyanion loss

May be triggered by a recent infection or an immune stimulus. Most common in children. Responds to corticosteroids

Question 4

Amyloidosis

Answer 4

Light microscopy: congo red stain shows apple-green birefringence under polarized light

associated with chronic conditions (i.e. multiple myeloma, TB, RA)

Question 5

Membranoproliferative glomerulonephritis

Answer 5

Type I: subendothelial IC deposits with granular IF; tram-track appearance due to GBM splitting caused by mesangial ingrowth

Type II: intramembranous IC deposits; dense deposits

Can also present as nephritic syndrome. Type I is associated with C3 nephritic factor

Question 6

Diabetic glomerulonephropathy

Answer 6

Nonenzymatic glycosylation (NEG) of GBM –> increased permeability, thickening.

NEG of efferent arterioles –> increased GFR –> mesangial expansion

Light microscopy: mesangial expansion, GBM thickening, eosinophilic nodular glomerulosclerosis (Kimmelstiel-Wilson lesion)