Transverse myelitis

Transverse myelitis is a rare neurological disorder characterized by inflammation across one segment of the spinal cord. It disrupts the normal transmission of nerve signals, leading to motor, sensory, and autonomic dysfunction. Early recognition and intervention are essential to optimize recovery and prevent long-term complications.

Definition and Classification

Transverse myelitis refers to inflammation of the spinal cord resulting in injury to both sides of one or more segments, leading to varying degrees of neurological impairment. It is distinguished from other spinal cord disorders by its characteristic pattern and clinical presentation.

• Definition: Acute or subacute inflammation of the spinal cord affecting both motor and sensory pathways.
• Acute vs chronic transverse myelitis: Acute forms develop rapidly over hours to days, while chronic forms may evolve more gradually or persist long-term.
• Idiopathic vs secondary forms: Idiopathic cases have no identifiable cause, whereas secondary cases result from infections, autoimmune disorders, or demyelinating diseases.
• Association with demyelinating disorders: Transverse myelitis can occur in multiple sclerosis, neuromyelitis optica, or other systemic autoimmune diseases.

Epidemiology

Understanding the epidemiology of transverse myelitis helps in identifying at-risk populations and planning healthcare resources. Although rare, it affects individuals across all age groups and both sexes.

• Incidence and prevalence: Estimated at 1–5 cases per million annually worldwide.
• Age and sex distribution: Can occur at any age, with a slight female predominance in autoimmune-related cases.
• Geographical variations: Reported incidence is similar globally, though specific infectious or autoimmune triggers may vary regionally.
• Risk factors and predispositions: Previous infections, autoimmune diseases, or recent vaccinations may increase susceptibility.

Etiology and Pathophysiology

Transverse myelitis can result from a variety of causes, all leading to inflammation and injury of the spinal cord. Understanding the etiology and underlying mechanisms is critical for diagnosis and treatment planning.

• Immune-mediated mechanisms: Autoimmune responses can target spinal cord tissues, causing demyelination and neuronal injury.
• Infectious causes: Viral infections such as herpes zoster, Epstein-Barr virus, and enteroviruses; bacterial and, rarely, fungal infections may trigger inflammation.
• Post-vaccination and post-infectious triggers: In some cases, immune responses following vaccination or systemic infection precipitate spinal cord inflammation.
• Vascular and ischemic causes: Reduced blood flow or infarction in the spinal cord may contribute to segmental damage resembling transverse myelitis.
• Demyelination and neuronal injury: Inflammatory processes lead to loss of myelin and axonal damage, impairing nerve conduction and resulting in neurological deficits.

Clinical Presentation

Patients with transverse myelitis present with a combination of motor, sensory, and autonomic symptoms, typically developing over hours to days. The pattern of symptoms depends on the level and extent of spinal cord involvement.

• Motor symptoms: Weakness or paralysis in the limbs below the level of the lesion, often symmetrical.
• Sensory symptoms: Numbness, tingling, burning sensations, or sensory loss corresponding to the affected spinal segments.
• Autonomic dysfunction: Bladder and bowel disturbances, urinary retention or incontinence, and sexual dysfunction.
• Onset and progression: Symptoms may present acutely within hours or subacutely over days, often peaking rapidly and stabilizing within 2–4 weeks.

Diagnostic Evaluation

Laboratory Investigations

Laboratory tests help identify underlying causes, rule out infections, and assess immune-mediated processes in transverse myelitis.

• Blood tests: Complete blood count, inflammatory markers, autoimmune panels including antinuclear antibodies and aquaporin-4 antibodies.
• Cerebrospinal fluid (CSF) analysis: Elevated protein levels, pleocytosis, and presence of oligoclonal bands may indicate inflammation or demyelination.

Imaging Studies

Imaging is essential for localizing lesions and evaluating the extent of spinal cord involvement.

• MRI of spinal cord: Detects lesions, their length, location, and inflammatory characteristics, differentiating from compressive causes.
• MRI of brain: Used to identify associated demyelinating diseases such as multiple sclerosis or neuromyelitis optica.

Electrophysiological Studies

Electrophysiological tests assess functional integrity of sensory and motor pathways.

• Somatosensory evoked potentials (SSEPs): Measure conduction along sensory pathways from the periphery to the cortex.
• Motor evoked potentials (MEPs): Evaluate corticospinal tract function and predict motor recovery.

Management

Acute Treatment

Immediate intervention in the acute phase of transverse myelitis is crucial to reduce inflammation and prevent further neurological damage.

• High-dose corticosteroids: Intravenous methylprednisolone is commonly administered to suppress inflammation and accelerate recovery.
• Plasma exchange (plasmapheresis): Considered in patients who do not respond to corticosteroids, helping remove pathogenic antibodies from circulation.
• Intravenous immunoglobulin (IVIG): Used in selected cases to modulate immune response and limit tissue injury.

Long-term Management

Ongoing care focuses on rehabilitation, symptom management, and maintaining functional independence.

• Rehabilitation: Physical therapy and occupational therapy to improve strength, mobility, and daily living skills.
• Management of spasticity and neuropathic pain: Pharmacologic interventions such as muscle relaxants, gabapentinoids, or botulinum toxin injections.
• Bladder, bowel, and autonomic dysfunction care: Catheterization, bowel programs, and monitoring to prevent complications.
• Psychological support and counseling: Addressing emotional impact, coping strategies, and quality of life.

Prognosis

The prognosis of transverse myelitis varies depending on the cause, severity of spinal cord involvement, and timeliness of treatment. Early intervention and comprehensive rehabilitation significantly influence recovery outcomes.

• Recovery rates: Approximately one-third of patients recover fully, one-third have moderate residual deficits, and one-third experience severe disability.
• Factors influencing prognosis: Rapid onset of symptoms, extensive spinal cord lesions, and poor initial motor function are associated with poorer outcomes.
• Risk of recurrence: Patients with associated demyelinating disorders such as multiple sclerosis may have a higher likelihood of recurrent episodes.

Complications

Transverse myelitis can lead to a variety of short-term and long-term complications, affecting multiple systems.

• Permanent neurological deficits: Persistent weakness, paralysis, or sensory loss below the level of the lesion.
• Chronic pain and spasticity: Neuropathic pain and increased muscle tone may impair mobility and quality of life.
• Bladder and bowel complications: Incontinence, retention, or chronic constipation due to autonomic dysfunction.
• Secondary musculoskeletal issues: Joint contractures, pressure sores, and osteoporosis due to immobility and reduced activity.

Prevention and Future Directions

Preventive strategies for transverse myelitis focus on reducing risk factors and advancing early intervention, while ongoing research aims to improve treatment and outcomes.

• Vaccination and infection control: Timely immunization and management of infections may help prevent post-infectious cases of transverse myelitis.
• Emerging therapies: Research into novel immunomodulatory treatments, including monoclonal antibodies and targeted biologics, aims to reduce inflammation and promote recovery.
• Neuroprotective strategies: Studies are exploring agents and techniques to preserve neural tissue, enhance remyelination, and prevent long-term deficits.
• Early diagnosis and intervention: Improved diagnostic tools and prompt management are critical to minimizing neurological damage and optimizing functional recovery.

References

1. Transverse Myelitis Consortium Working Group. Proposed diagnostic criteria and nosology of acute transverse myelitis. Neurology. 2002;59(4):499-505.
2. Wingerchuk DM, et al. Acute transverse myelitis: pathogenesis, diagnosis, and treatment. Clin Neuropharmacol. 2002;25(2):61-70.
3. Krishnan C, et al. Transverse myelitis: pathophysiology, diagnosis, and treatment strategies. Neurologist. 2004;10(1):2-13.
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7. Hughes RA, et al. Immunotherapy for transverse myelitis: current evidence and future directions. Autoimmun Rev. 2013;12(9):981-986.
8. Greenberg BM, Kerr DA. Clinical presentation and management of transverse myelitis. Curr Opin Neurol. 2011;24(3):280-285.