‘The disease that drives us crazy’: Diagnosing GCA vs polymyalgia rheumatica
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SAN DIEGO — Diagnosing giant cell arteritis and polymyalgia rheumatica can “fascinate” and cause “trepidation” in equal measure due to their similarities and complications, said a speaker at the 2024 Congress of Clinical Rheumatology West.
“These diseases fascinate us as clinicians,” Leonard Calabrese, DO, RJ Fasenmyer chair of clinical immunology at the Cleveland Clinic, and chief medical editor of Healio Rheumatology, told attendees. “We love to see these patients, but at the same time we have trepidation.”
According to Calabrese, that trepidation largely stems from a lack of sound diagnostics.
“In GCA, we have a test but it is imperfect,” he said, adding that there is not even an imperfect test for PMR.
Given the absence of a confirmatory test, Calabrese offered some pearls for diagnosing these two conditions.
“Cranial presentation is the most significant part of GCA,” he said.
However, he challenged the notion that a thickened temporal artery is present in every patient.
“It is a myth that you have to find this to diagnose giant cell arteritis,” Calabrese said.
Perhaps the most important consideration for physicians managing a patient with suspected GCA is visual loss, according to Calabrese. He added that it is essential to consider that patients may experience temporary or transient visual loss before they report it to a physician.
This symptom can then predict permanent visual loss.
“The highest risk of permanent visual loss is antecedent visual symptoms,” Calabrese said. “You have to ask about this in great detail. Visual loss in suspected GCA is a medical emergency.”
Another important consideration in GCA is jaw claudication. However, Calabrese urged attendees to actively discuss these symptoms with their patients.
“I have never had a patient in my life say, ‘I have had claudication in my jaw,’” he said.
Meanwhile, although C-reactive protein and erythrocyte sedimentation rate (ESR) can be useful in diagnosing GCA, Calabrese noted that they are “highly sensitive but not specific.”
“Also, what is a normal CRP and ESR in a 75-year-old person?” he said. “This is not a crisp and clear picture.”
Regarding the headache that patients may experience, Calabrese noted that this may also be non-specific.
“It can be posterior or anterior,” he said. “The vessels do not hurt. The most important pearl to keep in mind is that it is a new onset of a different type of headache.”
Shifting to PMR, Calabrese stressed that this condition can be even more challenging for clinicians.
“If the science tends to be more representative in GCA, the art tends to be more representative in polymyalgia,” he said. “This is the disease that drives us crazy. It is a mélange of different characteristics and nonspecific symptoms.”
According to Calabrese, PMR has a similar epidemiology and age range as GCA. He added that about two-thirds of cases are among women and most patients are of white, European descent.
The first question a rheumatologist should ask of a patient with suspected PMR pertains to morning stiffness, Calabrese said.
“I back away from a diagnosis of PMR unless there is significant stiffness in the morning,” he added.
Bilateral shoulder pain is also common.
“Patients with PMR have reduced range of motion in the shoulders that is restrictive,” Calabrese said. “It is an important physical finding in my experience.”
Elevated CRP and ESR are commonly present, while systemic presentations may include fever, night sweats, weight loss or anemia, according to Calabrese.
“A pearl for PMR is that patients often have an unexplained cough,” he said.
As a final consideration, clinicians managing a patient with suspected GCA or PMR should carefully consider all of the diagnostic procedures before proceeding.
“Ask yourself, is this the right diagnosis?” Calabrese said. “Does the patient have GCA or PMR? Because the treatment will be very different.”
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Calabrese L. The Art and Science of GCA and PMR. Presented at The Congress of Clinical Rheumatology West; Sept. 26-29, 2024. (hybrid meeting).
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