Abstract
In September 2009, a 79-year-old man developed pyrexia, malaise, and anorexia. A local clinic diagnosed active inflammation and renal failure (Cr, 2.3mg/dL). Since the symptoms were not relieved by an oral antibiotic and renal function deteriorated (Cr, 14.9mg/dL), he was referred to our hospital for further evaluation after 1 week. Daily hemodialysis was required because of anuria. Chest X-ray films showed pneumonia affecting the right lower lung field. Continuous fever and marked inflammation despite broad-spectrum antibiotic therapy suggested an autoimmune disease. Autoantibodies containing anti-neutrophil cytoplasmic antibody (ANCA) and anti-glomerular basement membrane (GBM) antibody were all within normal limits. A contrast-enhanced CT scan demonstrated irregular constriction of renal artery branches and low enhancement of the bilateral kidneys. Partial wall thickening of the jejunum and constriction of a jejunal artery branch were also seen. A renal biopsy demonstrated severe acute tubular necrosis without angiitis in small vessels and glomeruli. These findings suggested marked renal ischemia due to inflammation of medium-size renal arteries caused by classical polyarteritis nodosa (PN). Steroid pulse therapy followed by oral prednisolone (40mg daily) was administered, and his symptoms improved markedly. The prednisolone dose was gradually decreased to 10mg daily, and there have been no signs of recurrence for 1 year. Rapidly progressive renal insufficiency is rare in patients with classical PN. Early diagnosis and therapy are vital for successful treatment.
