<prompt> 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 -Goodpasteurs syndromeClassic polyarteritis nodosaWegeners granulomatosisKawasaki syndrome  <response>: Renal and pulmonary symptoms with positive c-ANCA suggest the diagnosis of Wegeners glomerulonephritis see above explanation.The clinical syndrome of Wegeners granulomatosis may be very similar to classical PAN or microscopic polyangiitis.Following facts will help you to differentiate Wegeners granulomatosis from other Two -Wegeners granulomatosis Vs classical PANWegeners granulomatosis involves small vessels arteriole, venule, capillary, while PAN involves medium size vessels.Wegeners granulomatosis is associated with c-ANCA, while classical PAN is not associated with ANCA.In Wegeners granulomatosis there is lung involvement, but not in classical PAN.In Wegeners granulomatosis, there is glomerulonephritis hematuria without hypertension, while in classical PAN there is hypertension without glomerulonephritis.In Wegeners granulomatosis, there is granuloma formation, while it is absent in classical PAN.Classical PAN shows microaneurysms which are absent in Wegeners granulomatosis.Wegners granulomatosis Vs microscopic polyangiitisWegeners granulomatosis is associated with c-ANCA, while MPA is associated with p-ANCA.Granuloma formation occurs in Wegeners granulomatosis, not in MPA.Lung cavities and nodules are seen in Wegeners granulomatosis, but not in MPA. 