This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
[{'content': 'A 7 year old male had non blanching rashes over the shin and swelling of knee joint with haematuria +++ and protein +. Microscopic analysis of his renal biopsy specimen is most likely to show? \nSelect and explain. \nA. Tubular necrosis, B. Visceral podocyte fusion, C. Mesangial deposits of IgA, D. Basement membrane thickening', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Henoch-Schonlein purpura is a small-vessel leukocytoclastic vasculitis associated with IgA subclass 1 deposition in vessel walls. It is most common in children and is often associated with an inciting infection, such as group A streptococcus or other exposure. There is a male predominance. It classically presents with palpable purpura in the lower extremities and buttock area; ahralgias; and abdominal symptoms, such as nausea, colic, and melena. A decrease in GFR is common with a nephritic presentation. The renal lesions are considered by most expes to be identical to those found in IgA nephropathy. Skin biopsy demonstrates leukocytoclastic vasculitis with IgA and C3 deposition. Ref: Watnick S., Dirkx T. (2013). Chapter 22. Kidney Disease. In M.A. Papadakis, S.J. McPhee, M.W. Rabow (Eds), CURRENT Medical Diagnosis & Treatment 2013.', 'role': 'assistant'}]