A 6-year-old boy has marked edema of the legs, accumulation of fluid in the abdomen, and a low blood serum albumin and total serum protein. his urine contains large amounts of protein. what is the most likely cause of edema?

This is a pediatric patient presenting with nephrotic syndrome. Nephrotic syndrome is a spectrum of disease in which there is increased excretion of albumin (albuminuria) leading to decreased overall serum albumin. Albumin is the protein mainly involved in maintaining the plasma oncotic pressure meaning it is responsible in keeping the fluids in the vascular space. Loss of albumin will cause the fluids in the vasculature to leak towards the interstitium causing the edema.

There are 3 types of nephrotic syndromes, from a simple steroid-sensitive disease to steroid-resistant disease: Minimal change disease, mesengial proliferation, and focal segmental glomerulosclerosis.