Visual hallucinations in giant cell arteritis: association with visual loss.

OBJECTIVE: To evaluate the frequency and characteristics of visual hallucinations (VH) in patients with giant cell arteritis (GCA) and to determine their relationship to other visual phenomena.

METHODS: This prospective study included 31 consecutive patients with GCA. All were asked whether they had experienced recent visual phenomena. Patients with visual symptoms underwent a comprehensive ophthalmologic examination. When unusual visual phenomena were reported, patients were asked to describe their nature, duration, and frequency of occurrence.

RESULTS: Visual symptoms occurred in 6 patients: permanent visual loss in 5 and amaurosis fugax in one. In 4 of the 5 patients with permanent visual loss, it was preceded by intermittent VH over a period of 1-10 days. Patients were aware of the unreal nature of the visions. Hallucinations disappeared within 2 weeks, but in one patient, recurred 6 months later in association with further visual deterioration.

CONCLUSION: The occurrence of visual hallucinations in patients with GCA-associated visual loss is more common than previously appreciated. As hallucinations preceded permanent loss of vision, this phenomenon may serve as a harbinger of imminent visual loss.