Giant cell arteritis: Rheumatologists, ophthalmologists better together
Affecting an estimated 228,000 people, giant cell arteritis is the most common blood vessel disorder among adults aged 50 years or older.
GCA causes inflammation of medium and large arteries in the body and without treatment, undiagnosed persons with GCA are high-risk for sudden and sometimes irreversible blindness and, in rare cases, tongue necrosis, making an accurate and timely diagnosis essential.
In this guest commentary, Brendan Antiochos, MD, Johns Hopkins Medicine assistant professor of medicine, spoke with Healio on the importance of collaboration between rheumatologists and ophthalmologists concerning testing, diagnosing and treating patients with GCA.
There is interest in enhancing our use of imaging for diagnosis and management of GCA. This includes both imaging of the temporal arteries and of the great vessels. Currently, I do not see much use of ultrasound for imaging of the temporal arteries in patients referred to our center. I personally do not order this test myself, as I am not convinced that standardized techniques for the acquisition or interpretation of ultrasound images of the temporal arteries are widespread. If a patient is in acute, untreated phase of the disease, I always try to obtain a temporal artery biopsy rather than imaging.
I do recommend obtaining imaging of the great vessels at least once in GCA patients, to look for evidence of large vessel involvement that could lead to aneurysms or stenotic lesions over a patient’s course. MRA is likely more sensitive for identifying subtler signs of active disease such as wall edema, but CTA can provide useful information as well. Not all patients require long term, serial imaging studies, but screening patients at least once early in their disease seems a prudent measure. There is interest in using PET imaging to assess large vessel disease activity, but I rarely (if ever) utilize this test for GCA patients.
I always like to point out to patients and trainees that GCA remains a largely clinical diagnosis. We have very few diagnostic tests available to accurately diagnosis – or definitively rule out – GCA. Among the entities that rheumatologists confront, GCA is one in which the history alone often provides the most important information. The diagnosis of GCA is simple when a temporal artery biopsy returns definitively positive. But in nearly all other scenarios, the rheumatologist’s clinical judgment, based mainly on the patient’s history, is the most valuable tool available to us. I struggle to recall any cases in which the result of an imaging test alone dictated the overall treatment strategy. Careful assessment of the patient’s symptoms and course, along with obtaining an accurate eye exam from an ophthalmologist, and a temporal artery biopsy when possible, can lead to reasonable treatment strategies in the great majority of cases.
Ophthalmologists, rheumatologists jointly manage GCA vision loss
Communication between these two specialties is important in appropriate management of GCA. As rheumatologists, we rely on our ophthalmology colleagues to provide information on patients’ retinal findings. Their expertise is critical in determining whether GCA (or a mimic) is a likely cause of visual loss. This is particularly important in patients who are unable or unwilling to undergo a temporal artery biopsy.
Rheumatologists may have more experience in assessing the systemic manifestations of GCA, or identifying indicators of an alternate, systemic disease. One would not expect an ophthalmologist to perform a detailed joint exam, auscultate for bruits, etc. Ophthalmologists do have the ability to discriminate between forms of retinal pathology that rheumatologists would not be able to identify on exam, providing crucial information in suspected cases of GCA.
One difference between these two specialties, when it comes to managing established GCA, is the level of comfort with administration of immunosuppression (i.e. prednisone). Some ophthalmologists may feel comfortable independently managing long term steroids, while many would ask for a rheumatologist to jointly manage this medication. Such cases require ongoing collaboration.
The main conflict I have seen arise with this diagnosis has been the following scenario: a patient is diagnosed with GCA by another specialty - ophthalmology, neurology, or some other field – and started on high dose steroids. The patient is then directed to follow up with a rheumatologist, with the expectation that the rheumatologist will assume responsibility for the long-term management of prednisone – yet when the rheumatologist later meets the patient, the rheumatologist is not convinced of the diagnosis of GCA, and was not involved early enough to assess the patient prior to the administration of steroids. The best way to avoid this problem is to involve all relevant fields early in the patient’s care, and come to some consensus as to the most appropriate treatment strategy.
In terms of approaches to treating vision loss: It has been my experience that both fields will initiate steroids for new GCA in similar fashion. This therapeutic approach has been used for a long time, and both rheumatologists and ophthalmologists seem to (largely) initiate steroids in similar fashion. Differences in treatment strategies might arise over the course of a patient’s illness. In general, I would expect rheumatologists to be more likely to initiate adjunct therapies such as Actemra or methotrexate than would your average ophthalmologist. There are certainly exceptions however - some ophthalmologists manage inflammatory ocular disease as a large portion of their practice and treat patients exactly as would a rheumatologist.
In terms of assessing risk factors for visual loss, I have been impressed by the ability of many ophthalmologists to take detailed history regarding the cranial symptoms of GCA; it’s my impression that rheumatologists and ophthalmologists review similar signs and symptoms of GCA that are predictive of visual loss when interviewing a patient. Ophthalmologists will of course have the ability to identify subtle exam findings of retinal injury caused by GCA that most rheumatologists would not be capable of recognizing with their ophthalmoscope (if they have one!).
- Lawrence, CR. Estimates of the Prevalence of Arthritis and Other Rheumatic Conditions in the United States, Part II. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3266664/. Accessed June 29, 2020.