Relation of giant cell arteritis to polymyalgia rheumatica.

Polymyalgia rheumatica and temporal arteritis appear to be separate syndromes rather than two manifestations of an underlying giant cell arteritis. Polymyalgia rheumatica is a synovitis that may be persistent or recurrent, while temporal arteritis is almost always a single episode; documented recurrences are rare. The two syndromes frequently occur in the same patient although not necessarily at the same time and they may be separated by a long interval. In some patients with polymyalgia rheumatica, giant cell arteritis is found on biopsy of an asymptomatic temporal artery. The frequency of this concurrence is variable in different populations. It is high in Scandinavia, low in Israel and intermediate between these extremes in other populations that have been studied.