Focal segmental glomerulosclerosis Flashcards
What is FSGS
Nephrotic syndrome with progressive renal impairment
Lesions of focal (some of the glomeruli) and segmental (involves part of the glomerular tuft)
Alterations of podocyte architecture
Idiopathic
Secondary - HIV, heroin, conditions causing reduced renal mass, Drugs, Familial, DM, HTN, Obseity, sickle cell disease, cyanotic congential heart disease
Features of Primary FSGS NOS
Focal segmental consoliation of glomerular tuft by increased extracell matrix obliterating capillary lumens
Commoner in males, and blacks
Nephrotic syndrome or subnephrotic proteinuria
Those who do not respond to steroid have poor prognosis (50% 5 year survival)
Prognostic sigificance: level of serum creatinine and severity of proteinuria at presentation
Histology
Solidification of segment of glomerulus by increased matrix and hyalinosis
Hyalinosis is PAS+ve, accumulates beneath glom BM. May have lipid vacuoles
Endocapillary foam cells
May involve perihilar, vascular pole, or peripheral regions
Adhesions/synechiae to bowman’s capsule
Detachment of podocytes may form a ‘halo’
Advanced lesions involve all the glomerulus
Patchy tubular atrophy, interstitial fibrosis
Interstitial foam cells singly and in aggregates
Proximal tubules may contain resorption droplets
IF of FSGS
Focal and segmental granular IgM, C3, variable C1
Also may show weak mesangial IgM
Intracytoplasmic protein droplets in podocytes and proximal tubule cells may stain for albumin and Igs
EM - wriking and retraction of glom BM, effacement of foot process above segmental sclerosis
DDx
MCD - as FSGS is focal, may not be sampled (lesions commonest in corticomedullary junction). Clue is patchy tubulointerstitial disease esp in abscence of HTN
Secondary FSGS caused by structural-functional adaptations do not usu have hypoalbuminaemia
Variants of FSGS
Cellular variant - focal and segmental glom hypercell - endothelial cells, foam cells, leukcocytes, karyorrhexis, podocyte hyperplasia
