A 12-year-old boy complains of swelling of his feet for the past 3 weeks. He is otherwise healthy, with no known previous illness. Vital signs are normal. Physical examination reveals pitting edema of the lower legs and a swollen abdomen. Urinalysis shows 4+ protein but no RBCs or WBCs. Which of the following are the most likely diagnoses to consider in your evaluation of this patient?

Minimal change glomerulopathy causes 90% of the nephrotic syndrome in young children and 15% in adults. Proteinuria is generally more selective (albumin > globulins) than in the nephrotic syndrome caused by other diseases, but there is too much overlap for this selectivity to be used as a diagnostic criterion. This disease is characterized pathologically by fusion (effacement) of visceral epithelial foot processes; however, this can be visualized only by electron microscopy. Minimal change glomerulopathy is successfully treated with corticosteroids and does not progress to renal failure. Focal segmental glomerulosclerosis (FSGS) is the cause of nephrotic syndrome in 10% of children and 30% of adults. FSGS is the term applied to a heterogeneous group of glomerular diseases that have different causes, including mutations, viruses, drugs, and serum factors. Henoch-Schonlein purpura and lupus nephritis (choice A) generally present with nephritic syndrome and rash, among other signs and symptoms. Wilms tumor (choice E) is not a cause of nephrotic syndrome.Diagnosis: Minimal change nephrotic syndrome