Idiopathic Acute Transverse Myelitis


KEY FACTS

Terminology

  • Inflammatory disorder involving both halves of spinal cord, resulting in bilateral motor, sensory, and autonomic dysfunction

Imaging

  • Central cord expansile lesion > 2 vertebral segments in length ± variable eccentric enhancement

Top Differential Diagnoses

  • Multiple sclerosis

  • Neuromyelitis optica

  • Spinal cord neoplasm

  • Spinal cord infarction

Pathology

  • Autoimmune phenomenon with formation of antigen-antibody complexes

  • Small vessel vasculopathy → cord ischemia

  • Associated demyelinating process

Clinical Issues

  • Inclusion criteria

    • Sensory, motor, or autonomic dysfunction (including bowel/bladder involvement) attributable to spinal cord

    • Bilateral signs/symptoms with well-defined sensory level

    • Compressive etiology excluded by neuroimaging

    • Cord inflammation confirmed by cerebrospinal fluid pleocytosis, elevated IgG index, or gadolinium enhancement

  • Exclusion criteria

    • History of spinal radiation within past 10 years

    • Cord ischemia/infarction, arteriovenous malformation

    • Connective tissue diseases

    • CNS infections, sarcoidosis, SLE, or Sjögren syndrome

Diagnostic Checklist

  • Central cord lesion > 2 vertebra in length, eccentric enhancement → consider acute transverse myelitis

  • More focal cord T2 hyperintensity, enhancement → more characteristic of multiple sclerosis

Sagittal T2WI MR demonstrates mild, multilevel cervical cord expansion with confluent intramedullary T2 hyperintensity
extending over 5 levels.

Sagittal T1WI MR (same patient) reveals mild cervical cord expansion with subtle central intramedullary hypointensity
. Lesion extent on T1 MR is usually less conspicuous than on T2 MR.

Axial T1WI C+ MR (same patient) illustrates patchy, bilateral, central heterogeneous cervical spinal cord enhancement
involving both gray and white matter.

Sagittal T1WI C+ MR (same patient) confirms extensive parenchymal enhancement within the abnormal dorsal cervical spinal cord
.

TERMINOLOGY

Abbreviations

  • Idiopathic acute transverse myelitis (IATM)

Synonyms

  • Idiopathic transverse myelopathy

Definitions

  • Inflammatory disorder involving both halves of spinal cord, resulting in bilateral motor, sensory, and autonomic dysfunction

    • Pathogenetically heterogeneous inflammatory disorder of spinal cord

IMAGING

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