<prompt> A child presents with brown colored urine and oliguria for last 3 days. He has mild facial and pedal edema. His blood pressure is 12690. He has 3 proteinuria with 100 red cell and a few granular casts. His creatinine is 0.9, urea is 56. What is his diagnosis?PSGNNephrolithiasisFSGNInfection associated glomerulonephritis  <response>: Ans. a PSGNRef: Nelson Text book of Pediatrics 20th Ed; Page No-2498 Ghats Essential Pediatrics 9th Ed; Page No-469 Most common cause of glomerulonephritis is immune mediated injury caused by Immune complexes and glomerular antigen mediated damage. It is characterized by the triad of hematuria, azotemia and hypertension. The most common cause of acute glomerulonephritis is that following streptococcal infection PSGN-Post streptococcal Glomerulonephritis.Post streptococcal Glomerulonephritis PSGN Acute post streptococcal Glomerulonephritis is caused by autoimmune injury only due to selective nephritogenic strains of streptococcus. The patient develops glomerulonephritis with streptococcal pharyngitis usually in winter after 1-2 weeks of infection and with streptococcal pyoderma in summer after 3-6 weeks of infection. Nephritogenic strains include types 4 and 12 pharyngitis and type 49 pyoderma.Clinical Features: The most common age o presentation is 5-12 years school- age children and is rarely seen before 3 years of age. The onset is rapid, with puffiness around the eyes and pedal edema. The patient presents with gross hematuria with smoky, cola or tea colour urine and hypertension. Peripheral edema typically results from salt and water retention. Complications that can be seen are hypertensive encephalopathy, pulmonary haemorrhage, cerebral vasculitis, hyperkalemia, hypophosphatemia and acidosis.Diagnosis Light microscopy: Proliferation of endothelial mesangial cells Fluorescence: Ig G, Ig M, and C3 deposits in mesangium. RBCs casts on urine analysis is a characteristic feature Urine shows 1-2 proteinuria Elation ASO titer In skin infection ASO titre remains normal-here elevated anti-DNAse B titers help in diagnosis.Management The treatment is usually suppurative most of the cases resolves spontaneously and rarely my progress to renal failure. Close monitoring of blood pressure and diet should be low in sodium and potassium. Fluid restriction. Diuretics e.g. frusemide for edema. Penicillin is usually given for infection however it does not alter the course of glomerulonephritis. Antihypertensive drugs Amlodipine, nifedipine or diuretics; hypertensive emergencies need treatment with IV nitroprusside or labetalol. 