Description

An acquired, immune-mediated inflammatory process in the spinal cord presenting as rapid onset (acute to subacute) weakness, sensory change, and/or autonomic dysfunction. Classically described with a sensory level (hence, “transverse”) although not required and less often described in children. Transverse myelitis (TM) is typically associated with MRI and CSF abnormalities consistent with acute inflammation. TM can be idiopathic (usually monophasic) or be a manifestation of a chronic relapsing inflammatory disorder such as multiple sclerosis (MS) or neuromyelitis optica spectrum disorder (NMOSD).

Epidemiology

• Incidence: estimated 1 to 8 per million cases per year, or 1,400 new cases, in the United States
• 20% are children (approximately 300 children affected per year).
• Bimodal age distribution is observed with peaks between ages 0 and 5 years and 10 and 17 years in children.
• Prevalence: estimated 34,000 people with chronic morbidity from TM in the United States
• No difference in ethnicity prevalence
• Female-to-male ratio is approximately 1:1 for children with idiopathic TM; female predominance can be observed if TM is a part of a relapsing syndrome such as MS or NMOSD.

Risk Factors

• Prodromal infections in up to 66% and vaccination in up to 28% in 30 days preceding onset of TM symptoms in children (although most data suggest that there is not a link between TM and vaccination)
• >1/3 may be disease associated (secondary TM).

General Prevention

Avoid unnecessary exposure to communicable diseases and obtain routine immunizations to protect against preventable diseases. Because some autoimmune disorders are linked to vitamin D deficiency, supplementation of vitamin D₃ may help prevent CNS inflammatory conditions.

Pathophysiology

Multiple mechanisms have been implicated due to the diverse spectrum of disease from idiopathic to disease-associated myelitis. Histopathology may reveal perivascular infiltration by monocytes and lymphocytes, demyelination, and axonal loss.

Etiology

Unknown, although molecular mimicry has been implicated, leading to immune response against infectious antigens with cross-reactivity to CNS proteins. Other theories include direct microbial infection of the spinal cord and superantigen-mediated disease.

Commonly Associated Conditions

• Predominately idiopathic, occurring as a postinfectious autoimmune process
• Infectious etiologies include but are not limited to West Nile Virus, human T-lymphotropic virus (HTLV)-1, HIV, Zika, influenza, enteroviruses, and herpes family viruses, mycoplasma, syphilis, Lyme disease.
• Can be a manifestation of a multifocal CNS disease (MS, NMOSD, acute disseminated encephalomyelitis [ADEM]) or paraneoplastic syndrome
• TM can be associated with systemic inflammatory diseases such as sarcoidosis, Sjögren disease, systemic lupus erythematosus, Behçet disease, antiphospholipid syndrome, scleroderma, ankylosing spondylitis, juvenile idiopathic arthritis, mixed connective tissue disease.