A 7 year old boy presented with generalized edema. Urine examination revealed marked albuminuria. Serum biochemical examinations showed hypoalbuminemia with hyperlipidemia. Kidney biopsy was undeaken. On light microscopic examination, the kidney appeared normal. Electron microscopic examination is most likely to reveal

Minimal change disease(MCD)Also known as nil lesion or lipoid nephrosis Causes 70-90% of the Nephrotic syndrome in childhood but only 10-15% of the Nephrotic syndrome in adultsCan be associated with Hodgkin&;s disease, allergies, NSAIDs, HIVClinical and laboratory findings: Abrupt onset of edema and nephrotic syndrome accompanied by acellular urinary sedimentHypeension, microscopic hematuria, allergic symptoms and decreased renal function may be presentAcute renal failure in adults is seen mostly in patients with low serum albumin and intrarenal edema (nephrosarca) that is responsive to intravenous albumin and diureticsIn children, the abnormal urine principally contains albumin with minimal amounts of higher-molecular-weight proteins, called as selective proteinuriaLight microscopy- no obvious glomerular lesionImmunofluorescent microscopy- negative for deposits or IgM deposits in mesangium(rarely)Electron microscopy- an effacement of the foot process with the weakening of slit-pore membranesPatients with steroid resistance may have FSGS on repeat biopsyPrimary responders: patients who have complete remission (<0.2 mg/24 h of proteinuria) after a single course of prednisoneSteroid-dependent: patients who relapse as their steroid dose is taperedFrequent relapsers: those having two or more relapses in the 6 months following taperSteroid-resistant: patients failing to respond to steroid therapyRelapses: - occur in 70-75% of children after the first remissionEarly relapse predicts multiple subsequent relapsesThe frequency of relapses decreases after pubey; increased risk of relapse following the rapid tapering of steroids in all groupsRelapses are less common in adults but are more resistant to subsequent therapyPrednisone is first-line therapy; cyclophosphamide, chlorambucil, and mycophenolate mofetil are used in frequent relapsers, steroid-dependent, or steroid-resistant patients(Ref: Harrison's 18/e p2345)