Purpose:
Hydroxychloroquine (HCQ) toxicity can be associated with poor visual prognosis if discontinued after the appearance of visible retinal changes. The purpose of this study is to report visual and anatomic findings in patients who discontinued HCQ due to toxicity.
Methods:
Retrospective review of patients who stopped HCQ due to toxicity identified 14 patients of whom 7 patients at Doheny and 4 at Northwestern had available follow up examinations using Humphrey visual field (HVF), fundus autofluorescence (FAF), and/or spectral domain optical coherence tomography (SD-OCT).
Results:
Mean patient age was 48.5 years (range 22-80), treatment duration 7.70 ± 5.96 years, cumulative dose 914.2 ± 870.6 grams, duration of follow up after toxicity diagnosis 11.5 months (range 1-36). At baseline, average HVF 10-2 defect depth was 6.71 ± 10.47 dB, HVF 30-2 mean defect (MD, -6.93 ± 30.33 dB) and pattern standard deviation (PSD, -17.80 ± 4.63 dB). Final follow up HVF 10-2 defect depth was 6.12 ± 9.88 dB (compared to baseline, p = 0.14), HVF 30-2 MD was -6.33 ± 24.92 dB (p = 0.5), and HVF 30-2 PSD was 17.50 ± 4.27 dB (p = 0.45). Of 11 patients with follow up, 8 were symptomatic. Of these, 5 patients had serial SD-OCT after stopping HCQ. Comparing baseline to 6 months follow-up showed thickening of the RPE and areas of re-establishment of the external limiting membrane and the inner/outer segment junction. (Figure) Two asymptomatic patients were diagnosed based on FAF abnormalities (normal SD-OCT and HVF 10-2) and one was diagnosed based on SD-OCT. None showed changes in FAF, SD-OCT, or HVF 10-2 after 1, 15, and 14 months of follow up, respectively.
Conclusions:
Patients with clinically visible lesions in HCQ toxicity showed borderline statistically significant visual improvement following drug cessation. They also showed evidence of outer retinal remodeling early after discontinuing HCQ on SD-OCT. Longer follow-up is needed for further functional improvements, if any. Patients without clinically visible lesions showed no improvements or worsening on FAF or SD-OCT. Our findings emphasize the importance of physician vigilance and early detection of HCQ toxicity using newer modality imaging approaches and long-term follow up after cessation.
Keywords: imaging/image analysis: clinical • drug toxicity/drug effects • retina