Skeletal muscle involvement has been well documented and muscular symptoms are common in patients with polyarteritis nodosa (PAN). However, the level of muscle enzyme is uncommonly elevated and overt rhabdomyolysis is very rare. We report a case of PAN presenting as rhabdomyolysis. A 22-year-old man was admitted because of fever, severe myalgia and swelling in all extremities. Laboratory investigations showed markedly increased levels of serum creatine kinase and myoglobin. There was diffusely increased muscular uptake in bone scan. Muscle biopsy from the right deltoid revealed vasculitis involving medium-sized vessel with ischemic necrosis of muscle. On angiography, saccular aneurysms were found in multiple arterities. Therapy with methylprednisolone pulse therapy and cyclophosphamide was followed by improvement of his symptoms.

Keywords: Polyarteritis nodosa, Rhabdomyolysis