ACCELERATED ONSET OF RETINAL TOXICITY FROM HYDROXYCHLOROQUINE USE WITH CONCOMITANT BREAST CANCER THERAPY

Accelerated hydroxychloroquine toxic retinopathy

PURPOSE

To report a case series of patients with retinal toxicity due to hydroxychloroquine (HCQ) within a short span of treatment.

METHODS

A retrospective review of case records of patients with accelerated HCQ toxicity within 1 year of starting the treatment was done. Systemic co-morbidities, details of HCQ treatment, details of ocular examination, and results of multimodal investigations were noted.

RESULTS

Nine patients (1 male, 8 females) with age ranging from 40 to 73 years (mean 54.2 ± 13.4 years) who showed accelerated HCQ toxicity were included. None had systemic conditions or drug history predisposing to early HCQ toxicity. The treatment duration ranged from 2 to 11 months and the cumulative HCQ dose ranged from 18 to 120 g (mean 45.0 ± 33.0 g). The visual acuity was normal in 8 (88.9%) patients and retinal evaluation was normal in 4 (44.4%). Optical coherence tomography was abnormal in 4 (44.4%). Six (66.6%) cases had reduced sensitivity in the parafoveal point on visual field testing. All 9 cases had multifocal electroretinographic changes diagnostic of HCQ toxicity. The HCQ treatment was stopped in 8 and continued with reduced dose in 1 patient. The mean duration of follow-up was 11.2 ± 9.6 months during which 5 patients showed improved mfERG and 1 patient had a stable mfERG. Visual fields improvement was noted in 2 cases.

CONCLUSIONS

Patients on HCQ need to be kept on regular monitoring with more frequent follow-ups to detect signs of early onset toxicity and prevent permanent visual impairment. mfERG is an important diagnostic tool for HCQ toxicity.

Hydroxychloroquine-induced Retinal Toxicity

Long-term use of hydroxychloroquine can cause retinopathy, which may result in severe and progressive visual loss. In the past decade, hydroxychloroquine use has markedly increased and modern retinal imaging techniques have enabled the detection of early, pre-symptomatic disease. As a consequence, the prevalence of retinal toxicity in long-term hydroxychloroquine users is known to be higher than was previously estimated. The pathophysiology of the retinopathy is incompletely characterised, although significant advances have been made in understanding the disease from clinical imaging studies. Hydroxychloroquine retinopathy elicits sufficient public health concern to justify the implementation of retinopathy screening programs for patients at risk. Here, we describe the historical background of hydroxychloroquine retinopathy and summarize its current understanding. We review the utility and limitations of each of the mainstream diagnostic tests used to detect hydroxychloroquine retinopathy. The key considerations towards a consensus on the definition of hydroxychloroquine retinopathy are outlined in the context of what is known of the natural history of the disease. We compare the current screening recommendations for hydroxychloroquine retinopathy, identifying where additional evidence is required, and the management of proven cases of toxicity. Finally, we highlight the areas for further investigation, which may further reduce the risk of visual loss in hydroxychloroquine users.