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': 'Marker for the renal vasculitis in children is – \nSelect and explain. \nA. Increased IgA level, B. Low complement level, C. ↑ Antineutrophilic cytoplasmic antibody titre, D. Increase antinuclear antibody', 'role': 'user'}, {'content': "Answer: A \nExplanation: IgA nephropathy or Berger's disease affects children and young adult and is perhaps the most frequent type of glomerulonephritis in children.\n\nIgA nephropathy (Berger nephropathy) \n\nIt is the most common type of glomerulonephritis worldwide.\nChildren and young adults are commonly affected.\nIt occurs after an upper respiratory tract infection or gastrointestinal infection.\n\nClinical presentation\n\nGross hematuria within 1-2 days after on upper respiratory tract infection. This feature distinguishes it from PSGN. In PSGN hematuria occurs 7-21 days after respiratory infection.\nCan also present with nephritic or nephrotic syndrome.\nMild to moderate hypertension.\n\nPathology\n\nFocal and segmental mesangial proliferation.\nIgA deposition in the mesangium.\nSerum complement level is normal. This feature also differentiates it from PSGN. In PSGN complement (C3) level is decreased.\nWhereas IgA nephropathy is isolated renal disease, similar IgA deposits are also found in systemic disorders of children like Henoch shonlein purpura, which also has renal vasculitis as a component fit view of the high frequency of IgA nephropathy in children, IgA can be used as a marker for renal vasculitis.", 'role': 'assistant'}]