Anti‐aquaporin‐4 antibody‐positive neuromyelitis optica spectrum disorder associated with central nervous system tuberculosis

Background Neuromyelitis optica spectrum disorder (NMOsd) is an inflammatory astrocytopathy that has both genetic and environmental cause. The exact etiology and pathogenesis of NMOsd is partially known, complex interactions between genetic and environmental factors are thought to be involved in its development. Infectious diseases have received particular attention, as they have long been considered to be triggers of many autoimmune disorders. Case presentation Here, we report two cases of positive aquaporin‐4 serostatus NMOsd in relation to granulomatous infection of the central nervous system. Both patients initially presented with active tuberculosis meningitis signs and symptoms with posterior development of longitudinally extensive transverse myelitis positive for anti‐aquaporin‐4 antibodies. Cerebral spinal fluid hypercellularity and elevated proteins were initially documented. The evolution was rather favorable, with clinical and radiological improvement based on antituberculous treatment and a cycle of i.v. steroids. Conclusions Although various cases of active pulmonary, renal and abdominal tuberculosis have been documented in association with NMOsd, no mechanism of association has been discovered; interestingly, the seropositive for NMOsd is variable. We theorized that a genetic background in our population might be associated with this uncommon phenotype. If this phenomenon corresponds to an immune dysfunction caused directly by the bacillus, direct tuberculosis infection or a cross‐reaction is to be determined.