In GCA, Two (New) Factors Inform Temporal Artery Biopsy Decision

February 13, 2015

Patient age and platelet count can inform the need for temporal artery biopsy in diagnosing giant cell arteritis, a retrospective study suggests.

De Lott LB, Burke JF, for the Michigan Neuro-Ophthalmology Research Consortium. Use of Laboratory Markers in Deciding Whether to Perform Temporal Artery BiopsyJAMA Ophthalmology. Published online February 05, 2015. doi:10.1001/jamaophthalmol.2014.5861

Aurélie Daumas A, Manon Scafi M, Estelle Jean E, et al. 18F-FDG PET hypermetabolism of vertebral arteries revealing Giant Cell Arteritis.  American Journal of Medicine. Online: February 03, 2015. doi: 10.1016/j.amjmed.2015.01.020

Two reports discuss giant cell arteritis (GCA) this week in non-rheumatology journals.

The first article above reveals that age at biopsy and platelet count help to signal patients withGCA, offering added guidance about whether to perform a temporal artery biopsy (TAB) or forgo its possible risks.

In a retrospective review of medical records for 404 selected patients who had TAB in eight institutions, the authors used logistic regression to estimate the association between all measured variables and biopsy results. After controlling for gender and clustering within institutions, as well as for the two clinical measures most often used to select patients for TAB-erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)-age at biopsy and platelet count continued to predict biopsy results.

TAB resultAge (mean)

Platelet Count
    (median)

Positive      77      391
Negative      73      275

The second article, a case study of an 85-year-old man admitted for symptoms suspicious of stroke, reminds readers of the ways in which stroke associated with GCA differs from that caused by atherosclerosis.

The man (whose age was well above that associated with positive TAB in the first study) did not have enlarged or tender temporal arteries. Did he have atherosclerosis, or inflammation?

18F-FDG PET/CT showed a high uptake invertebral arteries, without atheroma on ultrasound Doppler. The combination suggested GCA, which was confirmed by temporal artery biopsy. The patient was managed with prednisolone taper.

Compared to atherosclerosis-related stroke, giant cell arteritis (GCA)-related stroke more commonly affects the vertebrobasilar territory in the extracranial location.

The intracranial and intradural segments of these arteries are involved only rarely, because the elastic fibers, the target of the inflammatory response, are sharply reduced in the media and adventitia.