<prompt> An 8 year old child is brought with co severe abdominal pain. OE palpable purpura is noted. There is history of recent diarrhea which is completely resolved. What is the expected pathological finding in kidney?Podocyte effacement on electron microscopyElectron dense deposits in the Glomerular basement membrane on electron microscopyHypercellular glomeruli with neutrophils on light microscopyMesangial deposits of IgA on electron microscopy  <response>: HENOCH SCHONLEIN ANAPHYLACTOID PURPURA Most common systemic vasculitis in children 90 cases occur in the age group 3 to 10 years Immune complex deposition causing small vessel vasculitis Many cases of HSP follow a documented upper respiratory infection Characterized by the tetrad of Palpable purpura due to vasculitis, not due to thrombocytopenia - occur in gravitydependent areas lower extremities or on pressure points buttocks Polyarthralgia in the absence of arthritis non-deforming, oligoarticular, involves large joints, migratory Gl symptoms colicky abdominal pain, passage of blood and mucus per rectum, intussusception - in 80 children Mild glomerulonephritis IgA deposition in the mesangium, microscopic hematuria - in 50 children Chronic renal disease develops in 1-2 of children with HSP Approximately 8 of those with HSP nephritis go on to have end-stage renal disease Myocardial involvement can occur in adults but is rare in children Laboratory features ANCA negative Leukocytoclastic vasculitis with IgA deposition in the small vessels in the skin, joints, gastrointestinal tract kidney Deposition of C3, fibrin, and IgM are also seen to a lesser extent Elevated ESR Normal platelet count Normal complement levels Diagnosis, prognosis and treatment No laboratory finding is diagnostic of HSP; The diagnosis of HSP is a clinical one Treatment for mild and self-limited HSP is supportive Steroids are most often used to treat significant gastrointestinal involvement or other lifethreatening manifestations Predisone: useful in decreasing tissue edema, arthralgias, and abdominal discomfort; but does not alter overall prognosis nor prevent renal disease. The prognosis is excellent Deposits of IgA are also found in the glomerular mesangium in a variety of systemic diseases, including chronic liver disease,Crohns disease, gastrointestinal adenocarcinoma, chronic bronchiectasis, idiopathic interstitial pneumonia, dermatitis herpetiformis, mycosis fungoides, leprosy, ankylosing spondylitis,relapsing polychondritis, and Sjogrens syndrome. 