Focal segmental glomerulosclerosis (FSGS) is a pattern of glomerular injury characterized by sclerosis (scarring) affecting some glomeruli (focal) and only portions of the affected glomerular tuft (segmental). The primary form involves podocyte injury from circulating permeability factors that damage the podocyte foot processes, disrupting the glomerular filtration barrier and allowing massive protein loss into the urine (nephrotic-range proteinuria greater than 3.5 g/day). Secondary FSGS can result from hyperfiltration (obesity, reduced nephron mass), viral infections (HIV-associated nephropathy), drugs (heroin, pamidronate), or genetic mutations in podocyte proteins (nephrin, podocin). Clinical presentation includes nephrotic syndrome (proteinuria, hypoalbuminemia, hyperlipidemia, edema), and progressive renal function decline. The nurse monitors daily weights, measures edema, assesses urine for frothiness (proteinuria), monitors serum albumin, creatinine, and lipid levels, administers prescribed immunosuppressive therapy (corticosteroids, calcineurin inhibitors), manages fluid and sodium restriction, monitors for complications of nephrotic syndrome (thromboembolism, infection from immunoglobulin loss), and educates patients about the chronic nature of the disease.