The prognosis of tuberculous meningitis, a rare form of extrapulmonary tuberculosis, depends on the stage of treatment initiation. We report a fatal case of tuberculous meningitis. The patient had received successive tumor necrosis factor (TNF) antagonists and abatacept to treat juvenile idiopathic arthritis, with negative results for polymerase chain reaction and acid-fast bacilli on smear, had normal cerebrospinal fluid (CSF) adenosine deaminase and glucose levels. Six weeks post-admission, the CSF culture demonstrated Mycobacterium tuberculosis. The altered immunological responses caused by anti-TNF treatment made the diagnosis challenging. Clinicians should bear this in mind and, if suspected, treatment should be initiated immediately.