Clinical meaning
Minimal change disease (MCD) is the most common cause of nephrotic syndrome in children (accounting for 80% of childhood cases), characterized by podocyte foot process effacement visible only on electron microscopy with no abnormalities on light microscopy or immunofluorescence. The pathophysiology is hypothesized to involve T-cell-mediated release of a circulating permeability factor (not yet definitively identified) that damages podocyte foot processes, disrupting the charge-selective filtration barrier of the glomerulus. The loss of negatively charged heparan sulfate proteoglycans and the effacement of podocyte slit diaphragms allows massive leakage of albumin into the urine (nephrotic-range proteinuria). The clinical presentation includes sudden-onset generalized edema (periorbital in children, peripheral in adults), frothy urine, hypoalbuminemia, and hyperlipidemia. The nurse monitors daily weights, measures edema (periorbital on waking, dependent during the day), performs urine dipstick for proteinuria, monitors serum albumin, administers corticosteroid therapy (prednisone -- greater than 90% of children achieve complete remission within 8 weeks), monitors for steroid side effects (hyperglycemia, hypertension, mood changes, growth suppression), monitors for complications of nephrotic syndrome (thromboembolism, infection from immunoglobulin loss, particularly pneumococcal peritonitis in children), and educates families about the relapsing nature of the disease.