Widespread panarteritis, mainly affecting medium-sized arteries. Onset ages 20 to 50 in >50%. CNS involved in 25%. Systemic manifestations: fever, malaise, tachycardia, sweating, fleeting edema, weakness, pains in joints, muscles, or abdomen.

Neurologic manifestations: mononeuritis multiplex; diffuse sensorimotor peripheral neuropathy. Poor prognosis; 5-year survival 50%.

Treatment: corticosteroids, immunosuppressive drugs.

Inflammation of temporal artery with multinucleated giant cells in media. Onset after age 50, primarily in white people.

Treatment urgent to prevent visual loss. Early steroid therapy effective, unless visual loss already severe.

Shares with temporal arteritis: age onset; clinical syndrome, high ESR, pathology (giant-cell arteritis), course, response to
steroid therapy. Headache, visual loss less frequent than in temporal arteritis. Excellent long-term outlook.