Purpose: To report the incidence, visual symptoms, and ocular signs of occult giant cell arteritis in patients who initially presented with visual symptoms and ocular signs of giant cell arteritis. Occult giant cell arteritis was defined as ocular involvement by giant cell arteritis without any systemic symptoms and signs of giant cell arteritis.
Methods: In a prospective study from 1973 to 1995, we investigated 85 patients who had ocular involvement caused by giant cell arteritis and whose diagnosis of giant cell arteritis was confirmed on temporal artery biopsy. At the initial visit, patients were questioned specifically on systemic and ocular symptoms and signs of giant cell arteritis at or before the onset of visual disturbance. Erythrocyte sedimentation rate (Westergren) and C-reactive protein level were evaluated before the start of systemic corticosteroid therapy.
Results: Eighteen (21.2%) of 85 patients had occult giant cell arteritis. There was no significant difference in age and sex distribution between patients with and without systemic symptoms of giant cell arteritis. Although both groups of patients had abnormal erythrocyte sedimentation rate and C-reactive protein level, there was a significant difference in erythrocyte sedimentation rate (P < .0001) and C-reactive protein level (P=.0133), these being relatively lower in patients with occult giant cell arteritis. The ocular symptoms in the 18 patients with occult giant cell arteritis were visual loss of varying severity in 18 (100%), amaurosis fugax in six (33.3%), diplopia in two (11.1%), and eye pain in one (5.6%). Ocular ischemic lesions consisted of anterior ischemic optic neuropathy in 17 (94.4%), central retinal artery occlusion in two (11.1%), and cilioretinal artery occlusion in two (of 11 patients with satisfactory fluorescein angiography [18.2%]). The ocular symptoms and ischemic lesions were seen in a variety of combinations.
Conclusions: Because occult giant cell arteritis is a potential cause of blindness, its early diagnosis is the key to preventing blindness; it is important to recognize that 21.2% of patients with giant cell arteritis and visual loss do not have any systemic symptoms of giant cell arteritis. Thus, in persons older than 55 years, amaurosis fugax or visual loss, development of an acute ocular ischemic lesion (particularly arteritic anterior ischemic optic neuropathy), and abnormal C-reactive protein level, with or without elevated erythrocyte sedimentation rate and systemic symptoms, should raise a high index of suspicion for giant cell arteritis.