Tuberculous optochiasmatic arachnoiditis.

A 25-year-old man was admitted with fever, headache, vomiting and vision loss for 2 months. Clinical examination revealed neck stiffness, inability to perceive projection of light and papilledema. Magnetic resonance imaging (MRI) of brain showed nodular thickening of basal meninges with contrast enhancement and multiple ring-enhancing lesions [Figures 1 and 2]. Cerebrospinal fluid was suggestive of tubercular meningitis with positive polymerase chain reaction for tuberculosis (TB-PCR).

Figure 1

(a) MRI T1-weighted image showing diffuse hypointensities involving bilateral internal and external capsules, thalamus, medial temporal and brainstem, (b, c) hyperintensities on T2w MRI in corresponding regions; and (d) fluid accentuated inversion recovery (FLAIR) sequence

Figure 2

(a) MRI brain with contrast (axial) showing multiple enhancing lesions (tuberculoma) with meningeal enhancement and with dilation of temporal horns of third ventricle suggestive of hydrocephalus; (b) meningeal enhancement and exudates in quadrigeminal cistern; (c) spoiled gradient recall echo (SPGR) showing meningeal enhancement with exudates; (d) coronal SPGR showing meningeal enhancement along Sylvian fissure; and (e) MRI sagittal T1 contrast image showing contrast enhancing lesions in basifrontal, mid brain tectum and ventral Pons along with enhancement of basal meninges

Tuberculous meningitis predominantly affects basal regions of brain, causing accumulation of exudates in suprasellar, Sylvian and interpeduncular cisterns, manifesting as optochiasmatic arachnoiditis (OCA).[1] It usually occurs in young individuals and causes slowly progressive vision loss.[2]