What is Transverse Myelitis?
Transverse myelitis is an acute inflammatory disease of the spinal cord characterized by rapid onset of bilateral motor weakness, sensory disturbances, and autonomic dysfunction (bladder, bowel, and sexual impairment) that typically progresses to maximal severity within 10 days of symptom onset. 1, 2
Pathophysiology
- The condition involves focal inflammation of the spinal cord with perivascular monocytic and lymphocytic infiltration, demyelination, and axonal injury 3
- The inflammatory process primarily damages the spinal cord gray matter, causing upper motor neuron dysfunction above the lesion level 1
- This upper motor neuron involvement results in spastic paralysis with hyperreflexia (increased deep tendon reflexes), which is a key distinguishing feature from lower motor neuron disorders like Guillain-Barré syndrome 1
Clinical Presentation
- At maximal clinical severity, approximately 50% of patients develop complete paraparesis, nearly all have sensory disturbances, and 80-94% experience numbness, paresthesias, or band-like dysesthesias 2, 3
- Bladder dysfunction occurs in virtually all patients, with urinary retention and constipation being common autonomic manifestations 1, 3
- Symptoms evolve rapidly over hours to days, with most patients reaching peak severity within 10 days 2
- The bilateral nature of symptoms with a sensory level below the lesion is characteristic 4
Etiologic Categories
The causes are diverse and can be classified into several broad categories 4:
- Demyelinating conditions (multiple sclerosis, neuromyelitis optica spectrum disorder) 5
- Autoimmune disorders (systemic lupus erythematosus, Sjögren's syndrome, sarcoidosis) - particularly associated with antiphospholipid antibodies 5, 6
- Parainfectious causes (HIV, HTLV-1, viral infections) 5, 4
- Paraneoplastic syndromes 5
- Drug/toxin-induced 4
- Idiopathic - despite extensive workup, many cases remain without identified cause 2
Diagnostic Features on MRI
- MRI shows T2-weighted hyperintense lesions in the spinal cord that appear wedge-shaped on axial views and cigar-shaped on sagittal views 1
- Longitudinally extensive transverse myelitis (affecting ≥3 contiguous vertebral segments) should raise suspicion for neuromyelitis optica spectrum disorder 1, 5
- Multiple sclerosis typically presents with shorter lesions (<3 vertebral segments) 5
Prognosis
- Residual disability is divided approximately equally into three groups: severe disability, moderate disability, and minimal or no disability 2, 3
- Poor prognostic factors include extensive spinal cord lesions (≥3 vertebral segments), reduced muscle strength or sphincter dysfunction at presentation, and delayed treatment initiation (>2 weeks) 7
- Relapses occur in 50-60% of cases during corticosteroid dose reduction 7
Key Clinical Pitfall
The presence of increased deep tendon reflexes (spastic paralysis) is the critical distinguishing feature of transverse myelitis compared to conditions causing flaccid paralysis with reduced reflexes, such as Guillain-Barré syndrome or poliomyelitis 1