COTW 8/7/23
Can giant cell arteritis be diagnosed using ultrasound?
A 56- year-old female comes to your ED due to blurry vision and seeing flashers for the last 15 days. A review of systems shows that the patient has been having claudication while eating and headaches that have been sporadic but very bothersome. you do some labs, and her sedimentation rate is about 65. You are thinking of temporal arteritis as a differential diagnosis, but you are concerned about giving her high-dose steroids since her past medical history includes diabetes, hypertension, and the patient reports that she has had previous episodes of iatrogenic Adison's disease since she got tired of taking her medications last time she was provided with high dose steroids when she was 35 for an MS flare that she had. Can point of care ultrasound help you make an informed decision for this patient?
Branches of the external carotid artery
Giant Cell Arteritis (GCA) is the most common systemic vasculitis in elderly patients. physical exam and history findings are very nonspecific due to its variable presentations throughout the body. Catastrophic complications of this condition can lead to unilateral to bilateral sudden onset vision loss.
Although diagnosis of GCA is clinical. It requires temporal artery biopsy on an emergent basis. Depending on the patient, this evaluation might take longer than expected before the patient can be adequately managed and leading to visual complications if the patient is not treated promptly.
Treatment for this condition normally includes the use of high-dose steroids. In patients with high suspicion, but no diagnosis of this condition, this can lead to "just in case treatment.” This approach might lead to those patients who do not need the treatment requiring tapering doses and potential complications to their current chronic medical conditions.
You recently read a story in a subscription platform that some studies have documented the use of ultrasound for diagnosing GCA with high-frequency linear transducers (15-20MHz) on the temporal and axillary arteries with high accuracy (100% Sen, 100% Spec), so you decide to put the probe on the patient’s face.
A simple approach for evaluation of the temporal artery can be achieved with evaluation in longitudinal and transverse views bilaterally to evaluate for arterial wall thickening with arterial luminal narrowing and lack of compressibility of the wall. This is normally called the halo sign, described as a dark hypoechoic thick arterial wall measuring over 0.4 mm. Including color flow in the evaluation helps with wall measurement since it can help showing the true wall thickness without having to guess the distance with grainy or hard to guess border of the artery. It is always recommended to evaluate the whole temporal artery due to the presence of skip lesions.
Transverse view of temporal artery with Halo sign
Longitudinal view of Temporal Arteritis
After your scan, your patient has clean arteries, no halo sign in any of her temporal arteries. After careful discussion of your concern for her eye complaints and the need to take the steroids, she ends up choosing not to take the steroids because “Last time I got worse with
them” You both agree on following up with her rheumatologist since she has an upcoming appointment in 2 weeks and agree that she will wait for her evaluation and return to the ED if any worsening symptoms develop.