Differentiating COVID-19 and Giant Cell Arteritis

Although COVID-19 shares several clinical features with giant cell arteritis (GCA), recognizing specific symptoms more common in each could help clinicians discriminate between the diseases and pursue an appropriate treatment path, according to a study published in The Journal of Rheumatology.

“This is one of the most time-critical decisions in rheumatology: Failure to treat may result in blindness, but misdiagnosis of GCA can lead to inappropriate immunosuppression and a missed opportunity to treat the real underlying cause of the symptoms,” the international team of researchers explained.

The study summarized findings from a pair of systematic reviews—one focused on GCA, the other on COVID-19—that investigated symptoms associated with each disease.

Overlapping features of both GCA and COVID-19 include headache, fever, elevated C-reactive protein (CRP), and cough, researchers reported. However, several clinical features were more discriminatory: jaw claudication, vision loss, platelet count, and lymphocyte count.

Rates of jaw claudication and vision loss were 43% and 26%, respectively, in patients with GCA, but neither tended to be reported in those with COVID-19, according to the review. Similarly, elevated platelet count occurred in 47% of patients with GCA but just 4% of patients with COVID-19.  

On the other hand, lymphopenia seemed to point toward COVID-19. More than half of patients with COVID-19 had an abnormally low level of lymphocytes in the blood, yet just 2% of those with GCA experienced lymphopenia.

“Physicians should be aware of the possibility of diagnostic confusion,” researchers advised. “We have designed a simple checklist to aid evidence-based evaluation of patients with suspected GCA.”

—Jolynn Tumolo

Reference

Mehta P, Sattui SE, van der Geest KSM, et al. Giant cell arteritis and COVID-19: similarities and discriminators. a systematic literature review. J Rheumatol. 2021;48(7):1053-1059.