Population-based Rate and Patterns of Diplopia in Giant Cell Arteritis.

Giant cell arteritis (GCA) is the most common vasculitis in older adults with permanent vision loss as a feared complication. Diplopia has been reported in a small percentage of patients with visual manifestations. The goal of this study was to determine the population-based rates and patterns of binocular diplopia from GCA. The Rochester Epidemiology Project (REP), a medical records linkage system was used to identify all residents of Olmsted County, Minnesota, USA, diagnosed with GCA between January 1, 1950 and December 31, 2019. Medical records were then reviewed to identify patients with binocular diplopia from GCA. There were 301 incident cases of GCA from 1950 to 2019. Fourteen (5%) patients presented with binocular diplopia. Of these 14 patients, nine (3%) had constant diplopia and five (2%) had transient diplopia. Among patients with constant diplopia, cranial nerve VI involvement was suspected in four (44%) cases. Systemic symptoms and inflammatory markers were similar in patients with and without diplopia. There was no difference in the rate of anterior ischaemic optic neuropathy between the two groups (7% vs. 7%, p = 1.00). In conclusion, this population-based study showed that binocular diplopia was present in 5% of patients with GCA, which could either be transient or constant. GCA patients with diplopia had similar systemic manifestations and risk of vision loss as GCA patients without diplopia.