Objective:

To present a case of longitudinally-extensive transverse myelitis (LETM) associated with interleukin-17 (IL-17) inhibitor treatment.

Background:

Transverse myelitis (TM) is a rare, acquired nontraumatic myelopathy that can cause irreversible motor, sensory, and autonomic impairments. More severe cases involve lesions spanning three or more vertebral segments, known as LETM. While demyelinating diseases like multiple sclerosis and neuromyelitis optica are common causes, both infectious and non-infectious etiologies have been implicated. LETM is rarely linked to immunobiologics such as tumor necrosis factor-alpha (TNF-alpha) inhibitors but has not been associated with IL-17 inhibitors.

Design/Methods:

N/A

Results:

A 55-year-old female with psoriatic arthritis treated with secukinumab presented with acute-onset right leg numbness, tingling, and weakness. Symptom progressed quickly that she had numbness and weakness in the contralateral leg the next day, followed by lower abdominal numbness, and loss of sphincter control. Neuro exam showed paraplegia with a sensory level at T11-T12 dermatomal distribution.  She also had reduced rectal tone, areflexia on both knees and ankles. Spinal MRI showed a non-enhancing T2 hyperintense lesion extending from T10 to the conus medullaris. CSF studies revealed lymphocytic pleocytosis and elevated protein levels, otherwise unremarkable. Oligoclonal bands, as well as serum and CSF aquaporin-4 and MOG antibodies, were negative. she received empiric intravenous immunoglobulin for LETM. Repeated spinal MRI showed extended lesion to the T6 level and later with enhancement on affected area. Plasmapheresis was initiated without improvement.

Conclusions:

Demyelinating diseases like multiple sclerosis and neuromyelitis optica are most common causes of LETM. Rarely LETM has been reported to be associated with immunobiologics such as tumor necrosis factor-alpha (TNF-alpha) inhibitors. Our case is the first one thought be to be associated with IL-17 inhibitors.