Delayed Longitudinally Extensive Transverse Myelitis Following Disseminated Tuberculosis: Expanding the Spectrum of Non-HIV Central Nervous System Immune Reconstitution Inflammatory Syndrome

Background: Paradoxical inflammatory reactions are increasingly recognised during treatment of central nervous system tuberculosis (CNS-TB), even in HIV-negative individuals. Longitudinally extensive transverse myelitis (LETM) developing after apparent microbiological resolution of tuberculosis is uncommon and presents a significant diagnostic challenge. Case description We report a 22-year-old immunocompetent male who initially presented with constitutional symptoms and abdominal distension, followed by acute progressive paraparesis. Evaluation revealed disseminated tuberculosis with CNS involvement manifesting as myeloradiculopathy and spinal tuberculomas. He improved clinically and radiologically with anti-tubercular therapy and corticosteroids. However, after completion of 12 months of therapy, he developed longitudinally extensive transverse myelitis (LETM) despite resolution of tuberculomas and persistently negative microbiological studies. Aquaporin-4 and myelin oligodendrocyte glycoprotein antibodies were negative. The delayed appearance of LETM following apparent microbiological recovery raised a diagnostic dilemma between a late paradoxical inflammatory response and post-infectious seronegative autoimmune myelitis. Partial improvement following corticosteroid therapy supported an inflammatory mechanism. Conclusion Delayed LETM following apparent microbiological cure of disseminated tuberculosis may represent an unusual manifestation of non-HIV central nervous system immune reconstitution inflammatory syndrome (CNS-IRIS) or tuberculosis-triggered autoimmune myelitis. This case highlights the evolving spectrum of post-tuberculous neuroinflammation and emphasizes the importance of considering immune-mediated mechanisms when neurological deterioration occurs despite adequate anti-tubercular therapy.