Temporal artery biopsy is a useful test for diagnosing giant cell arteritis but may miss some cases, research shows.
The findings, by Alexandros Drosos, M.D., of the University of Ioannina in Greece were published March 29 in PLos ONE.
The authors report that, “TAB (temporal artery biopsy) is a useful procedure that helps in this direction (diagnosis of giant cell arteritis), but unfortunately, it lacks sensitivity.”
Temporal artery biopsy with histologic examination is currently the gold standard for diagnosing giant cell arteritis. Other non-invasive diagnostic tools are available such as computed tomography, magnetic resonance imaging, positron emission tomography, and ultrasound. Although invasive, temporal artery biopsy offers an objective diagnosis where as imaging techniques produce a subjective determination based on the clinician’s observations.
The authors sought to determine the impact of temporal artery biopsy with histological examination on the clinical diagnosis in patients suspected of giant cell arteritis based on symptomology.
The findings are based on data analysis of patient records going back 17 years that included 245 patients who had elevated erythrocyte sedimentation rate and or C- reactive protein and clinical symptomology consistent with giant cell arteritis.
Patients who were referred by ophthalmology appeared to have the most positive temporal artery biopsies (83.3 percent) while orthopedic referrals resulted in the least.
Only 20 percent of temporal artery biopsies were positive even though patients met the American College of Rheumatology diagnostic criteria for giant cell arteritis.
Take-home points for clinicians and final thoughts
There is no 100 percent accurate diagnostic test for giant cell arteritis. Even though temporal artery biopsy is considered the gold standard for diagnosing giant cell arteritis, the European League Against Rheumatism stresses the importance of imaging as a first test for its diagnosis. The authors show that simply relying on imaging or clinical criteria may lead to over treatment with steroids, a therapy with it’s own risks.
The authors point out that, “TAB still has its place when a diagnostic doubt after the application of imaging techniques exists, but also when the recommended imaging modalities are not available or even when there is no sufficient experience by the operator.”
Clinicians should balance suspicion based on presenting signs and symptoms with caution when considering an invasive diagnostic test but keep in mind that many of the symptoms associated with giant cell arteritis can arise from simple infections or be non-serious forms of headache.
Eye symptoms in particular should be taken seriously since referrals based one these symptoms had a high rate of positivity for giant cell arteritis.
If strong suspicion of giant cell arteritis is held, steroids should begin immediately due to the serious nature of potential complications. Confirmation should be attempted with temporal artery biopsy even though its sensitivity is low.
The authors state, “The management of GCA requires a balance between ensuring that patients with GCA are diagnosed and treated appropriately and avoiding the burden of unnecessary steroids treatment.”
For a clinician, these results are less then satisfying. When a test has a sensitivity of less than 50 percent it means that many cases could be missed. This underscores the importance of clinical judgment. The consequences of not treating giant cell arteritis warrant treatment based on experienced clinical suspicion. The dangers of long-term steroid therapy must be weighed against that level of suspicion.
Temporal artery biopsy will remain a tool for diagnosing giant cell arteritis and may be used in conjunction with modern imaging techniques at centers where they are available and with clinicians skilled at interpreting them.
Kaltsonoudis E, Pelechas E, Papoudou- Bai A, et al. “The impact of temporal artery biopsy for the diagnosis of giant cell arteritis in clinical practice in a tertiary university hospital.” PLoS ONE 14(3): e0210845. https://doi.org/10.1371/journal. PMID.0210845