Diagnosing and managing polymyalgia rheumatica and temporal arteritis

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# Sensitivity of temporal artery biopsy varies with biopsy length and sectioning strategy {#article-title-2} Editor—Two recent review articles have discussed the diagnosis and management of giant cell arteritis.1 2 Both mentioned temporal artery biopsy, but the complexities of this deserve further discussion. Firstly, temporal artery biopsy is not perfectly sensitive. Medical students learn of the existence of skip lesions and that patients should not be denied steroid treatment for giant cell arteritis that is strongly suspected despite a negative biopsy result. Sensitivity is usually measured against a gold standard test, but for giant cell arteritis no such test exists. Probably the most sensible gold standard is a persisting clinical diagnosis at long term (say, one year) follow up. Secondly, clinicians should be aware that the sensitivity of biopsy will depend on quality, particularly biopsy length, and preparation for histological examination; a longer biopsy sample with closely spaced sections is likely to have a higher sensitivity than a short one with widely spaced sections. Supporting evidence for the various opinions about optimal biopsy length and preparation is lacking. The largest published series is from the Mayo Clinic.3 The clinic's recommended practice is to take specimens of substantial length (mean 35 mm) with a further specimen from the artery on the other side if the first gives a negative result on frozen section; despite this, many centres still take considerably shorter specimens.4 5 My audit of 200 temporal artery biopsy specimens sent to the neuropathology laboratory of the Western General Hospital, Edinburgh, between 1990 and 1996 showed a median biopsy length of only 10 mm. The specimens came from various departments, and the median length did not vary between departments. However, there was a significant difference in length between samples that gave positive and negative results on histological examination (1), which suggests that longer specimens may be more likely to yield a positive …