Treatment for Longitudinally Extensive Transverse Myelitis (LETM)

Diagnostic Approach

The American College of Neurology recommends a neurologic consultation to guide diagnosis and management of LETM 3
MRI of the spine with thin axial cuts showing T2-weighted hyperintense lesions extending across three or more vertebral segments is a defining feature of LETM 3
Lumbar puncture analysis, including cell count, protein, glucose, oligoclonal bands, viral PCRs, and onconeural antibodies, is essential for diagnosis 3, 4
Blood tests, such as aquaporin-4 IgG antibodies, MOG-IgG antibodies, autoimmune panel, infectious disease screening, vitamin B12, and thyroid function tests, are necessary for evaluating underlying causes 1, 3, 4

The American College of Neurology recommends immediately discontinuing any potential causative agents, such as immune checkpoint inhibitors, in patients with LETM 1, 4
High-dose intravenous methylprednisolone (1g daily for 3-5 days) combined with intravenous immunoglobulin (IVIG) 2g/kg over 5 days is the recommended first-line treatment for LETM 1, 2
Plasma exchange therapy may be considered for patients who do not respond adequately to corticosteroids and IVIG within 7-10 days 1
Rituximab may be beneficial in cases with positive autoimmune antibodies or inadequate response to other therapies 1, 3

For LETM associated with neuromyelitis optica spectrum disorder (NMOSD), more aggressive immunosuppression may be required 1
For immune checkpoint inhibitor-related LETM, permanently discontinuing the immune checkpoint inhibitor is necessary in addition to other treatments 4
Evaluating and managing urinary retention and constipation, common autonomic manifestations, is crucial 2, 3

Factors associated with poor prognosis include extensive spinal cord MRI lesions, reduced muscle strength or sphincter dysfunction at presentation, and delay in initiation of therapy 1

The presence of increased deep tendon reflexes is a key distinguishing feature of LETM compared to conditions with flaccid paralysis like Guillain-Barré syndrome 2