Ophthalmological manifestation in patients of tuberculous meningitis.

Background: Vision impairment, blindness in particular is a devastating complication in patients with Tubercular meningitis. However information regarding ophthalmological manifestation and its impact on vision is sparse in the literature. This study evaluated the spectrum of ophthalmological manifestations in tuberculous meningitis, including retinal nerve fiber layer thickness assessment by optic coherence tomography and its correlation with visual and clinical outcome.

Material and methods: This was a prospective observational study done from October 2015 to March 2017. Consecutive patients of tuberculous meningitis, diagnosed as per consensus case definition were included in the study. The patients were divided into two categories, uncomplicated and complicated tuberculous meningitis. Clinical evaluation, cerebrospinal fluid examination and contrast enhanced MRI of brain was done. Detailed ophthalmological evaluation including optic coherence tomography was done in all patients. All the patients were followed for 6 months. The primary outcome was blindness or low vision after six months. The secondary outcome was death or severe disability after six months. It was defined as Modified Barthel Index ≤ 12 at six months (including disability plus death). Appropriate statistical analysis was done.

Results: Out of 101 patients of tuberculous meningitis, 47 patients of TBM belonged to uncomplicated category, while 54 patients were of complicated group. The visual impairment was present in 24 out of 101(23.76%) patients out of which 20 (19.8%) patients had low vision while 4(3.96%) had blindness. The visual impairment was more evident in complicated group, low vision 0.03(1.2-31.5). The most common abnormality on fundus examination was papilledema (22.8%).The complicated group had more incidence <0.0001(19.6 -48). Optic atrophy was found in 3 patients while choroid tubercles were found in 8 patients (All complicated TBM group). RNFL thinning was noted in 10 patients in both the eyes. On univariate analysis, presence of diplopia at baseline, impairment of colour vision at baseline, visual impairment at baseline, cranial nerve VIthinvolvement, optic atrophy and papilledema at baseline, RNFL thinning, abnormal VEP and baseline MBI were associated with poor visual outcome. On multivariate analysis none of the factors were found to be independently associated with poor visual outcome. On univariate analysis many factors including baseline MRC staging, altered sensorium, seizure, hemiparesis, basal exudates, infarcts, optochiasmaticarachnoiditis, visual impairment at baseline were found to be associated with poor clinical outcome at 6 months.On multivariate analysis, presence of seizures (p = 0.047, odds ratio = 78.59, 95% confidence interval (1.07-578.72) was the only factor found to be independently associated with poor outcome.

Conclusion: Wide spectrum of ophthalmological manifestation was observed in patients of tuberculous meningitis. The visual impairment was more evident in complicated tuberculous meningitis. Ophthalmological findings like optic atrophy, papilledema and RNFL thinning were associated with poor visual outcome on univariate but not multivariate analysis. Visual impairment at baseline, among other factors was associated with poor clinical outcome on univariate analysis, whereas seizure was the only factor independently associated with poor outcome on multivariate anlaysis.