Is a biopsy required to make a diagnosis of Giant Cell Arteritis?
Often, but not always. Classification schemes (not used for diagnostic purposes) have classically required three of five criteria: age >50 years, new headache, temporal artery abnormality, elevated ESR, and characteristic biopsy findings. In clinical care, the gold standard for diagnosis has traditionally been a temporal artery biopsy with characteristic features; however, recent advances in imaging now allow for a diagnosis of GCA in the absence of biopsy data in many situations. Ultrasound, CTA, magnetic resonance imaging (MRI)/MRA, and fluorodeoxyglucose (FDG)-PET techniques have altered the diagnostic algorithm in GCA, allowing for increased reliance on imaging. New classification criteria using these imaging modalities are in development. A reasonable diagnostic algorithm based on recent European League Against Rheumatism (EULAR) recommendations is detailed below