Focal Segmental Glomerulosclerosis (FSGS)

Abstract

AbstractFocal segmental glomerulosclerosis is a type of podocytopathy characterized by a focal and segmental increase in the mesangial matrix with scarring and obliteration of the glomerular capillary lumen. According to Columbia classification, various morphological variants such as NOS, perihilar, collapsing, tip, and cellular have been identified. The prognostic significance of these variants is debatable. Based on etiopathogenesis, FSGS has also been classified into primary and secondary FSGS. The secondary FSGS could be associated with various conditions such as maladaptive as in obesity, drug induced, viral infections, and genetic forms (autosomal dominant, recessive, X-linked) or mitochondrial. FSGS can also be encountered in post-transplant settings, both recurrent and de novo forms have been recognized. Primary FSGS is thought to be the result of a circulating factor that causes podocyte injury and patients have nephrotic syndrome. It shows diffuse podocyte foot process effacement and responds well to steroids, plasmapheresis, or immunomodulatory agents. Secondary FSGS shows focal foot process effacement; it usually has subnephrotic proteinuria which requires renin–angiotensin–aldosterone inhibitors and resolution of an offending agent like virus or drugs.