Purpose:
Early detection of Plaquenil toxicity (PT) prior to irreversible structural changes has remained an elusive goal. The purpose of this study was to identify the earliest changes detected on autofluorescence (AF) and spectral domain OCT (SD-OCT) in both symptomatic and asymptomatic patients with PT.
Methods:
A retrospective chart review was performed on all patients taking Plaquenil, who were referred to the Doheny Eye Institute between 2006-2009. Patients underwent fundus photography, autofluorescence (HRA; Heidelberg Engineering, Heidelberg, Germany), IR, and OCT (Spectralis®, Heidelberg Engineering, Heidelberg, Germany).
Results:
A total of 21 patients were referred to the Doheny Eye Institute to rule out PT. Eight patients were found to have evidence of PT (average age 57 years), while the remaining 13 patients did not (average age 52 years). In patients with PT, the average dose, duration, and consequent cumulative dose were 325 mg/day, 8.3 years and 984.6 grams respectively, compared to 299 mg/day, 6.9 years, and 753 grams in patients without PT. In those patients where height and weight were recorded, the average for those with PT was 4’11 and 134 lbs, compared to 5’7 and 154 lbs for those without (p < .034). SD-OCT findings in the setting of symptomatic PT ranged from mild focal photoreceptor layer loss to diffuse outer retinal thinning, and correlated well with AF, FA, and ERG findings. Two of our patients developed asymptomatic PT, without visible changes on SD-OCT, but demonstrated increased AF in a bull’s eye pattern.
Conclusions:
As previously reported, PT was associated with older age, increased dosage, as well as longer duration of Plaquenil use. Short stature was also significantly correlated with PT, perhaps reflecting that surface area is a more accurate index for dosing than body weight. In addition, we found that AF may detect RPE changes in asymptomatic patients, even before structural changes are visible on SD-OCT.
Keywords: imaging/image analysis: clinical • drug toxicity/drug effects • retina