Longitudinally Extensive Transverse Myelitis: A Retrospective Study Differentiating Neuromyelitis Optica Spectrum Disorder From Other Etiologies.

Background Longitudinally extensive transverse myelitis (LETM) is characterized by contiguous immune-mediated inflammatory lesion of the spinal cord extending more than three vertebral segments. Neuromyelitis optica spectrum disorder (NMOSD) is the most common and important cause of LETM. This study aims to evaluate the demographic profile, clinical presentations, neuroimaging features, laboratory parameters, and etiologies of LETM and differentiates NMOSD from other etiologies of LETM. Methodology This retrospective cross-sectional study was conducted at the Department of Neurology, Tribhuvan University Teaching Hospital, Kathmandu, Nepal. After receiving clearance from the ethical committee, a retrospective chart review was conducted and records of all the inpatient LETM cases admitted from March 2018 to June 2020 were obtained. From the patient records, the following information was extracted: the demographic profile, clinical presentations, neuroimaging features, cerebrospinal fluid analysis, serum anti-aquaporin-4 (AQP4) immunoglobulin G status, hemogram, infectious disease profile, inflammatory markers, and auto-immune panels. Descriptive analysis of data was performed with SPSS statistics 23.0 version (IBM Corp, Armonk, NY, USA). Results In our study, the mean age of LETM patients was 36.58 years, and 12 out of 19 (63.15%) patients were young, with an age less than 40 years. A total of 13 (68.40%) patients were male, with a male-to-female ratio of 2.16. Seven (36.80%) patients had a clinical diagnosis of NMOSD with anti-AQP4 antibody-positive status, four (21.10%) had unknown etiology, three (15.8%) had post-infectious transverse myelitis, and three (15.80%) had a diagnosis of idiopathic transverse myelitis. There was a single case (5.30%) of cervical spondylotic myelopathy and leukemic transverse myelitis each. The common presenting symptoms of LETM were bladder dysfunction, paraparesis, quadriparesis, and visual impairment. Visual involvement, either unilateral or bilateral, was common in NMOSD and LETM of unknown etiology category. Similarly, brain lesion was common in patients with NMOSD and LETM of unknown etiology category. Conclusion LETM is a heterogeneous disorder with diverse etiologies and clinical presentations. NMOSD is an important cause of LETM that predominantly affects females. Optic neuritis can be seen in LETM of various etiologies, but it is more common in anti-AQP4-positive NMOSD patients. Brain lesions in LETM are common in anti-AQP4-positive NMOSD.