LIVERPOOL, ENGLAND — Giant cell arteritis is a critical ischemic process and should be considered a preventable stroke in the eye, yet vision loss almost always occurs before treatment is begun, according to Dr. Bhaskar Dasgupta.
Giant cell arteritis (GCA), the most common of the vasculitides, has an incidence of 7–29/100,000 people aged 50 and older in Europe, notably among women. The mean age of onset is 70 years.
GCA predominantly affects the cranial branches of arteries arising from the arch of the aorta, and often coexists with polymyalgia rheumatica (a generalized stiffness and aching of the muscles around the neck and shoulders), said Dr. Dasgupta, who headed a working group of the British Society for Rheumatology that has drafted guidelines for the management of GCA.
While new onset headache and elevated inflammatory markers are typical, GCA does not always present classically—particularly in patients at highest risk for neuro-ophthalmic complications.
“Pitfalls for the unwary include the fact that GCA does not always present with headache, and we now know that jaw claudication is a cardinal red flag warning of imminent vision loss,” Dr. Dasgupta said at the annual meeting of the British Society for Rheumatology.
Immediate institution of high-dose corticosteroids is needed to avoid loss of vision. Biopsy of the temporal artery also should be done, but treatment should not be delayed in the interim.
American College of Rheumatology criteria for GCA include age of onset 50 years or more, new onset headache, temporal artery abnormalities, elevated erythrocyte sedimentation rate, and abnormal artery biopsy. But other features—jaw and tongue claudication, diplopia, and amaurosis fugax—should be considered the “TIAs” of critical ischemia, said Dr. Dasgupta, a consultant rheumatologist at Southend University Hospital, Westcliff (England).
“The concept of symptom-to-thrombolysis time in myocardial infarct and stroke is well established. We believed that 'symptom-to-steroid' time should be adopted as an audit standard in GCA,” Dr. Dasgupta said in an interview.
Histologic findings on biopsy of the temporal artery can include mononuclear cell infiltration; granulomatous inflammation, usually with multinucleated giant cells, intimal proliferation, and vascular occlusion. The biopsy should preferably be done within a week of starting steroid therapy, but may remain positive for 14–28 days after treatment is initiated. A trial of corticosteroids should not substitute for the biopsy, Dr. Dasgupta said.
The usual starting dose of prednisone 40–60 mg/day should be continued until symptoms and laboratory abnormalities resolve. However, in the setting of evolving vision loss or amaurosis fugax, intravenous methylprednisolone, 500 mg to 1 g daily for 3 days followed by oral prednisone, should be used.
The steroids should not be tapered too quickly—certainly not before 4 weeks, Dr. Dasgupta cautioned. But because GCA tends to follow a chronic relapsing course and long-term corticosteroid therapy in these patients is associated with a high rate of adverse events—in one series nearly half of patients had fractures—various immunosuppressive therapies have been tried. Though methotrexate trials have had conflicting results, the drug was shown in a meta-analysis to have a small effect in preventing relapses, he said. There have also been promising case reports of biologics.
“In my view the timing of treatment is the most important factor. Our approach to GCA today is almost leisurely compared to the modern approach to critical ischemia at other sites such as the myocardium and the brain,” Dr. Dasgupta said.
At left: optic neuritis associated with GCA, characterized by a pale disc with diffuse edema, splinter shaped hemorrhages, and optic atrophy. Center: an example of central retinal artery occlusion in GCA. At right: a histology of giant cell arteritis. Photos courtesy Dr. Bhaskar Dasgupta
Jaw Claudication: An Important Sign
Dr. Dasgupta also presented a poster at the meeting of the case of an 81-year-old woman with a 3-day history of complete vision loss in the right eye and 2 weeks of intermittent blurred vision in the left eye.
She had been seen by her general practitioner 4 weeks earlier with jaw claudication but had no history of headache, scalp tenderness, or polymyalgia rheumatica. She was not referred for exclusion of giant cell arteritis (GCA) or given corticosteroids.
At Southend Hospital, she was unable to perceive light in her right eye and had minimal vision in the left. The right optic disc was swollen and pale and the retinal arteries were attenuated, while there was pallor and blurring of nasal margin of the left optic disc. Both temporal arteries were thickened, wrote Dr. Frances A. Borg, Dr. Dasgupta's colleague. Erythrocyte sedimentation rate was 27 mm/hr and C-reactive protein (CRP) was 13 mg/L. Temporal artery biopsy confirmed GCA, revealing severe mediointimal proliferation.