RESUMO
Purpose: To study visual recovery and identify the factors that may affect it in patients with ethambutol-induced optic neuropathy (EON). Patients and Methods: Medical charts of patients who developed optic neuropathy after ethambutol (EMB) treatment for tuberculosis infection were retrospectively reviewed. Demographic details and clinical data were examined to assess visual recovery after discontinuation of ethambutol treatment. The univariate and multivariate relationships between various factors and visual recovery were evaluated using regression analysis. Results: Of 5394 patients diagnosed with tuberculosis infection and treated with EMB, 23 patients (0.43%) were diagnosed with EON. Logistic regression analysis found that female sex was the categorical factor significantly associated with good visual recovery with an odds ratio of 12.0 (95% confidence interval 1.56, 92.29; p = 0.02), while linear regression analysis identified good initial visual acuity as the numerical factor significantly related with it (p < 0.001). After adjustment with multivariate analysis, initial visual acuity was found to be the only significant factor associated with visual recovery. All patients with initial visual acuity of better than 20/200 at first visit achieved good visual recovery. Conclusion: The incidence of EON in patients treated with EMB was 0.43% in this hospital-based study. Good visual recovery was noted in 39.13% of these patients, and initial visual acuity was the factor that affected visual recovery. It is recommended that patients on EMB have regular screening by an ophthalmologist for early detection of the disease, and if it is discovered, that the use of the drug be immediately discontinued in order to prevent potentially devastating visual loss.
RESUMO
Background: The purpose of this research was to investigate the characteristics, clinical manifestations, incidence, and risk factors in ethambutol-induced optic neuropathy (EON) in the Thai population. Methods: Patients treated with ethambutol for tuberculosis (TB) were retrospectively identified in the medical record of a tertiary hospital in Thailand from January 2012 to August 2019. Development of EON was determined through review of ophthalmology records. Comparison was made between patients with EON and those without EON to identify possible risk factors. Ophthalmic outcomes were characterized. Results: Among 4,141 patients who received ethambutol for TB treatment, 1,062 had an ophthalmology encounter, and 20 (0.5% overall, 1.88% with ophthalmology encounters) developed EON. In unadjusted analysis, compared to patients without EON, those with EON had a similar daily dose, but longer duration of ethambutol treatment (P=0.02). They were older (mean 43.74 vs. 58.60 years, P=0.001), more likely to have hypertension (P=0.02) and smoke (p=0.01). There were no differences in gender, body mass index, diabetes, dyslipidemia, HIV infection or glomerular filtration rate. The peripapillary retinal nerve fiber layer, ganglion cell analysis, and vascular density as measured using retinal optical coherence tomography were impacted by EON. In adjusted logistic regression analysis, age greater than 60 (OR = 8.71, p = 0.01) and smoking (OR = 7.06, p = 0.01) were independent risk factors for EON. Conclusion: In patients treated with ethambutol, the incidence proportion of EON was 0.5% among those with ethambutol administered and 1.88% among those with ethambutol and an eye visit. Potential EON risk factors were age, hypertension, smoking, and duration of ethambutol medication. Smoking has not been associated with EON in prior studies.
