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: Pathology
[{'content': "A patient presents with respiratory symptoms i.e. a cough, hemoptysis and glomerulonephritis. His C-ANCA levels in serum were found to be raised. The most likely diagnosis is - \nSelect and explain. \nA. Goodpasteur's syndrome, B. Classic polyarteritis nodosa, C. Wegener's granulomatosis, D. Kawasaki syndrome", 'role': 'user'}, {'content': "Answer: C \nExplanation: Renal and pulmonary symptoms with positive c-ANCA suggest the diagnosis of Wegener's glomerulonephritis (see above explanation).\nThe clinical syndrome of Wegener's granulomatosis may be very similar to classical PAN or microscopic polyangiitis.\nFollowing facts will help you to differentiate Wegener's granulomatosis from other Two -\n\nWegener's granulomatosis Vs classical PAN\n\nWegener's granulomatosis involves small vessels (arteriole, venule, capillary), while PAN involves medium size vessels.\nWegener's granulomatosis is associated with c-ANCA, while classical PAN is not associated with ANCA.\nIn Wegener's granulomatosis there is lung involvement, but not in classical PAN.\nIn Wegener's granulomatosis, there is glomerulonephritis (hematuria) without hypertension, while in classical PAN there is hypertension without glomerulonephritis.\nIn Wegener's granulomatosis, there is granuloma formation, while it is absent in classical PAN.\nClassical PAN shows microaneurysms which are absent in Wegener's granulomatosis.\n\n\nWegner's granulomatosis Vs microscopic polyangiitis\n\nWegener's granulomatosis is associated with c-ANCA, while MPA is associated with p-ANCA.\nGranuloma formation occurs in Wegener's granulomatosis, not in MPA.\nLung cavities and nodules are seen in Wegener's granulomatosis, but not in MPA.", 'role': 'assistant'}]