Early onset monocular hydroxychloroquine maculopathy in a systemic lupus erythematosus patient with history of central retinal artery occlusion: a case report

BACKGROUND: Hydroxychloroquine is a widely used medication for various clinical conditions mainly rheumatological and dermatological autoimmune diseases e.g. systemic lupus erythematosus, rheumatoid arthritis and psoriasis. While it is considered a safe medication, it is well-established that it can cause retinal toxicity i.e. HCQ maculopathy. Guidelines for HCQ retinal toxicity screening include factors like body weight, daily dose, duration, systemic diseases and retinal diseases. In this case study, we report a specific association between CRAO as a retinal disease and early onset HCQ maculopathy in a SLE patient. CASE PRESENTATION: A 42-year-old Caucasian female SLE patient presented with a complaint of gradual progressive painless diminution of vision in the left eye that started 16 months earlier. Clinical evaluation of the patient revealed a history of sudden profound painless diminution of vision in the same eye 18 months earlier after which the patient experienced only partial improvement of vision. That episode of sudden diminution of vision was attributed to left CRAO, complicating SLE-related thrombophilia, confirmed by fundus fluorescein angiography. Based on that diagnosis, the patient had been prescribed HCQ. At the time of presentation, fundus examination revealed left bull's eye maculopathy and right normal fundus. Therefore, a diagnosis of HCQ maculopathy in the left eye was made after exclusion of other causes of unilateral bull's eye maculopathy. CONCLUSION: Our case study is the first to report an association between CRAO as a specific retinal disease and early onset of HCQ maculopathy in a SLE patient. The unilateral bull's eye presentation which occurred in the eye with CRAO after only 16 months of HCQ treatment highly suggests that CRAO is probably the cause of such unusually early maculopathy. This case report highlights the importance of retinal diseases as risk factors for HCQ maculopathy. It also points out the lack of specific evidence concerning the association between specific retinal diseases and HCQ maculopathy.