Polyarteritis nodosa in association with subarachnoid hemorrhage.

We report a 65-year-old man with classic polyarteritis nodosa (PAN) who developed subarachnoid hemorrhage. Polyarteritis nodosa was strongly suspected, however, the biopsy specimens of kidney and sural nerve showed no findings of vasculitis and the serum titer of antimyeloperoxidase-antineutrophil cytoplasmic autoantibody (MPO-ANCA) was negative. Cranial magnetic resonance angiography showed no findings of aneurysms. He developed subarachnoid hemorrhage (SAH) during the course and died. Autopsy confirmed fibrinoid necrosis in the medium-sized artery of multiple organs. To our knowledge, this is the first report of a case of classic PAN accompanied by SAH in which MPO-ANCA proved negative.