FFS: Transverse myelitis

Transverse myelitis may present as an isolated condition or as part of other neuro-inflammatory disorders, such as:

• Multiple sclerosis
• Neuromyelitis optica spectrum disorder (NMOSD)
• Acute disseminated encephalomyelitis (ADEM)
• Myelin oligodendrocyte glycoprotein antibody disease (MOGAD)
• Acute flaccid myelitis (AFM)

In the Emergency Department, it is vital to exclude compressive structural lesions requiring urgent neurosurgical intervention. MRI is the imaging modality of choice.

Epidemiology

• Rare condition
• Bimodal peak incidence: 10–20 years and 30–40 years
• No known familial predisposition

Pathophysiology

Lesions may occur anywhere in the spinal cord, most commonly in the thoracic region. While the cause is often unknown, proposed mechanisms include infections and autoimmune processes.

Causes include:

1. Idiopathic

• Up to 30% have no identifiable cause
• Often post-infectious (viral), or post-vaccination (rare, unproven causation)

2. CNS autoimmune diseases

• Multiple sclerosis
• Neuromyelitis optica spectrum disorder (anti-AQP4)
• Acute disseminated encephalomyelitis (ADEM)
• MOGAD (anti-MOG)
• Acute flaccid myelitis

3. Systemic inflammatory autoimmune disorders

Includes:

• Sarcoidosis
• Sjögren syndrome
• SLE
• Less commonly: RA, systemic sclerosis, Behçet’s, etc.

4. Paraneoplastic syndromes

Most commonly associated with:

• Small cell lung cancer
• Antibodies: anti-Hu, CRMP5, anti-amphiphysin

Subtypes of transverse myelitis

Subtype	Features
Acute partial	Mild/asymmetric, MRI: 1–2 vertebral segments
Acute complete	Symmetric deficits, MRI: 1–2 vertebral segments
Longitudinally extensive (LETM)	Lesion spans ≥3 vertebral segments
Gray matter-centric (e.g. AFM)	Lower motor neuron features, flaccid weakness

Differential diagnosis

• Compressive spinal cord lesions (disc, malignancy, epidural abscess/haematoma)
• Guillain-Barré syndrome
• Anterior spinal artery infarction
• B12/folate deficiency
• Nitrous oxide abuse

Clinical features

• Acute or subacute onset over hours to days
• Usually bilateral symptoms (not necessarily symmetric)
• Defined sensory level
• Motor signs: upper/lower motor neuron, flaccid then spastic
• Autonomic signs: bladder/bowel/sexual dysfunction
• Pain: not common; may suggest intense inflammation or alternative diagnosis

Natural history

• Partial recovery in most idiopathic cases within 1–3 months
• Full recovery may take years
• Persistent disability in ~40%
• Poor prognosis with rapid complete paraplegia
• MS-associated cases often recur

Diagnostic criteria (Transverse Myelitis Consortium)

Inclusion:

• Bilateral signs/symptoms
• Defined sensory level
• MRI excludes compressive lesion
• CSF inflammation or gadolinium enhancement
• Symptom nadir: 4 hrs – 21 days

Exclusion:

• Prior spinal radiation
• Vascular distribution deficits
• MRI flow voids suggesting AV fistula
• Known CNS infection or connective tissue disease
• MS-type brain MRI or optic neuritis (for idiopathic TM)

Investigations

Bloods:

• FBE, U&E, CRP, ESR, glucose
• B12, folate, syphilis serology
• Autoantibodies: AQP4, MOG, ANA, ENA, dsDNA, RF, ANCA
• Paraneoplastic: anti-Hu, CRMP5, anti-amphiphysin
• HIV, INR (esp. if on warfarin)

Imaging:

• MRI spine + brain: best test; lesion ≥3 segments common
• CT: to exclude structural lesion if MRI unavailable

Lumbar puncture:

• Lymphocytosis, ↑ protein
• Normal glucose

EMG: may assist prognostication

Management

Corticosteroids (for idiopathic acute TM):

• Methylprednisolone 30 mg/kg (max 1 g) IV daily x 3–5 days

Plasma exchange (if motor impairment or steroid-resistant):

• 5 exchanges over 10 days or alternative spaced regimen

Disposition

All suspected transverse myelitis cases require neurology referral.

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References

Publications

• Transverse Myelitis Consortium Working Group. Proposed diagnostic criteria and nosology of acute transverse myelitis. Neurology. 2002 Aug 27;59(4):499-505
• Frohman EM, Wingerchuk DM. Clinical practice. Transverse myelitis. N Engl J Med. 2010 Aug 5;363(6):564-72.atPearls
• Sharma R. Transverse myelitis. Radiopaedia

FOAMed

• Coni R. Cranial neuralgias. LITFL
• Hayes J. FFS: Headache – Neuralgic Chart. LITFL