Context: Longitudinally extensive transverse myelitis (LETM) is defined as a hyperintense spinal cord lesion extending over three or more vertebral levels on sagittal T2-weighted spinal magnetic resonance imaging (MRI). Among the different causes of LETM, neuromyelitis optica (NMO) is the most common and associated with bad prognosis.
Aims: We aimed to study the clinicoradiological profile, etiology, and prognosis of LETM.
Settings and design: This is a hospital-based cross-sectional prospective study.
Subjects and methods: The study included 37 patients who presented with paraplegia/paresis or quadriplegia/paresis with MRI spine showing LETM. They were analyzed for their clinical features, routine blood parameters, MRI findings, serum aquaporin 4 (AQP4) antibodies. All patients were followed up for 1 year for prognosis.
Statistical analysis used: Data analysis was performed using SPSS software (version 17, SPSS Inc.; Chicago, IL, USA). The different groups were compared with each other using Chi-square test.
Results: The mean age in our series was 35.97 ± 13.2 years. There was a slight female predominance of LETM in our series with a female: male ratio of 1.05:1. Thoracic spinal cord segments were the most commonly (56.76%) affected. The tendency to involve three to five segments is more common (40.54%). Serum AQP4 antibody (Ab) test was done in 26 patients with LETM. Among them, AQP4 Ab was found positive in nine patients (34.62%). A total of 22 patients (59.46%) were clinically diagnosed as NMO, 4 patients as postinfectious myelitis, 1 each in tuberculous myelitis and subacute combined degeneration, and 9 were idiopathic LETM. Prognosis of LETM in the form of Expanded Disability Status Scale at 1 year was poor in patients with NMO particularly those with positive AQP4 Ab.
Conclusion: NMO is the most common cause of LETM. Because of poor prognosis of LETM in patients with NMO, particularly those with positive AQP4 Ab, it is very essential for early and accurate diagnosis of etiology of LETM, so that appropriate treatment can be provided to the patient.
Keywords: Aquaporin 4 antibody; longitudinally extensive transverse myelitis; multiple sclerosis; neuromyelitis optica.