title: Diagnosis of giant cell arteritis: when should we biopsy the temporal artery?
abstract: Giant cell arteritis (GCA) can be diagnosed histopathologically by biopsy of the temporal artery, and clinically using the 5-point score of the 1990 American College of Rheumatology (ACR) classification. We aimed to find out whether some patients are referred for biopsy unnecessarily. We audited all referrals (n=100) made to the Department of Oral and Maxillofacial Surgery over 34 months, and used the ACR classification to find out whether patients had had a clinical diagnosis of GCA at referral (ACR score: 3 or more). We then compared them with the result of the biopsy. Of the 100 referred, 98 had a biopsy, and of them, 15 were diagnosed with GCA (2 results were not included). Thirteen of the 15 had already been diagnosed clinically (based on the ACR classification) at referral. Our results gave an ACR specificity of 96% (95% CI: 85% to 99%) but only 20% sensitivity (95% CI: 11% to 32%). There was a linear correlation of high ACR scores with histopathological confirmation. Biopsy is most beneficial when there is a degree of diagnostic uncertainty (ACR: 1 or 2), an atypical presentation, or when steroids may be relatively contraindicated. On the basis of our study, we designed a new referral form for biopsy based on the ACR criteria.
authors.affiliation: Oral and Maxillofacial Department, Doncaster and Bassetlaw Foundation Trust. Electronic address: omarthusain@yahoo.com.
authors.forename: Omar
authors.initials: O
authors.lastname: Hussain
authors.affiliation: Liverpool University Dental Hospital.
authors.forename: Andrew
authors.initials: A
authors.lastname: McKay
authors.affiliation: Rheumatology department Chesterfield Royal Hospital.
authors.forename: Kevin
authors.initials: K
authors.lastname: Fairburn
authors.affiliation: Oral and Maxillofacial department Chesterfield Royal Hospital.
authors.forename: Peter
authors.initials: P
authors.lastname: Doyle
authors.affiliation: Oral and Maxillofacial department Chesterfield Royal Hospital.
authors.forename: Robert
authors.initials: R
authors.lastname: Orr
mesh_terms: D001706:Biopsy; D013700:Giant Cell Arteritis / Q000175:diagnosis*; D006801:Humans; D012017:Referral and Consultation; D012680:Sensitivity and Specificity; D013699:Temporal Arteries
keywords: Giant Cell Arteritis; Temporal Cell Arteritis; Temporal artery biopsy