Arachnoiditis, especially caused due to tuberculosis, is a potentially treatable cause and hence the necessity for its recognition.

Arachnoiditis of the adhesive type is albeit a rare complication of tubercular meningitis, which this patient has a history of. The exudate lies posteriorly due to gravity and hence the adhesive nature of the nerve roots to the periphery of the thecal sac giving the appearance of the empty thecal sac sign.