Longitudinally extensive transverse myelitis with positive aquaporin-4 IgG associated with dengue infection: a case report and systematic review of cases

Background: : Neuromyelitis Optica Spectrum Disorder can be associated with parainfectious and post-infectious triggers. Dengue virus infection is one of the most common arbovirus infections in the world, and may present with neurological manifestations. Objectives:: We present a case of DENV-associated with LETM and positive aquaporin-4 IgG, and a systematic review of published cases. Methods: : Medline (Ovid) and PubMed were search through June 2021, for case reports, series and observational studies that described patients with DENV-associated LETM and/or NMOSD. Results: : An adolescent girl who had recently immigrated from a Dengue-endemic region presented with a LETM with high positive AQP4-IgG titer and seropositive DENV IgM/IgG antibodies. She responded well to steroids and subsequently started maintenance rituximab for her NMOSD diagnosis. Literature review: 22 publications describing 27 patients met inclusion criteria. In addition to this case, three published cases met current criteria for NMOSD with serological evidence of acute DENV infection. Conclusions: : It is unknown whether there is a pathophysiological association between DENV infection and NMOSD. Regardless, if an immune-mediated event is suspected, particularly NMOSD, appropriate immuno-therapy should be considered early. Decision regarding long term immunotherapy may depend on index of suspicion of true NMOSD, and this is where AQP4-IgG status and follow-up is helpful.