Written by Christopher Thom, MD RDMS
SAEM, Academy of Emergency Ultrasound
There is potential for an emerging role of ultrasound as an adjunct tool for the diagnosis of temporal arteritis.
Why does this matter?
Temporal arteritis (TA, aka giant cell arteritis) is a critical diagnosis to consider amongst patients with visual changes. The diagnosis classically relies upon pathological findings after a temporal artery biopsy (TAB). However, TAB can be difficult to obtain in an expeditious fashion, and this can lead to difficult decisions about the initiation of high dose steroids for presumptive treatment. Ultrasound is a potential adjunct for the diagnosis of TA that can be performed in a rapid and accurate fashion.
Having an eye for new uses of ultrasound
This review article discusses the emerging literature on ultrasound (US) for the diagnosis of TA and its potential implications for patient care. The appropriate location for arterial evaluation is the temporal artery and its branches.
Sonographically, one can visualize the ‘halo sign’, which results from an inflammatory infiltrate and edema of the tunica media. This produces a hypoechoic, thickened rim of the vascular wall (swelling) that does not disappear on compression. Additionally, one can see the ‘compression sign’, which is a visible persistence of the vessel wall on compression with the ultrasound probe.
The authors discuss several studies to illustrate the performance of US for the diagnosis of TA, with most using TAB as the gold standard. This includes a meta-analysis encompassing 998 patients wherein the sensitivity of US was 82% and specificity 75%. An additional study of 40 GCA patients using an intima-media pathological thickness cutoff of 0.42 mm demonstrated 100% sensitivity and 100% specificity.
Ultrasound for ocular complaints continues to have an important role in differentiating the etiology of acute visual changes amongst Emergency Department patients. While the above literature did not directly include Emergency Physician performed ultrasound, this application may be a tool worth adding to our point of care ultrasound toolbox in the future.
The role of vascular ultrasound in managing giant cell arteritis in ophthalmology. Surv Ophthalmol. 2020 Mar-Apr;65(2):218-226. doi: 10.1016/j.survophthal.2019.11.004. Epub 2019 Nov 24.