Cranial Ultrasound More Sensitive in GCA Diagnosis
Research presented at the European League Against Rheumatism Annual Congress (EULAR 2014) suggests that cranial ultrasound is superior in sensitivity and has comparable specificity in the diagnosis of giant cell arteritis (GCA) compared to temporal artery biopsy (TAB).
In 87 patients who underwent cranial ultrasound for suspected GCA between January 2005 and July 2013, 41% had a confirmed clinical diagnosis at the 3 month follow-up; of the 30 patients with a positive cranial ultrasound, 96% had a confirmed GCA diagnosis at 3 months. Only 58% of patients that had >3 American College of Rheumatology (ACR) criteria for GCA had a diagnosis of GCA confirmed at 3 months.
For clinical diagnosis at 3 months, the sensitivity of cranial ultrasound was 81%, specificity 98%, positive likelihood ratio 41, negative likelihood ratio 0.2, positive predictive value of 97%, and negative predictive value of 88% vs. sensitivity of 53%, specificity 100%, positive likelihood ratio 2.3, negative likelihood ratio 0.2, positive predictive value of 100% and negative predictive value of 47% with TAB.
There are currently no 100% accurate diagnostic tests for GCA and prompt treatment with high dose steroids is necessary to prevent permanent loss of vision. Cranial ultrasound could be beneficial in distinguishing GCA from other less serious causes of headaches.
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