Transverse myelitis is a rare but serious neurological disorder characterized by inflammation across one segment of the spinal cord, resulting in varying degrees of motor, sensory, and autonomic dysfunction. It may be an isolated incident, part of a broader autoimmune disease, or secondary to infections, medications, or toxins.
Understanding the diverse etiological landscape of transverse myelitis is critical for timely diagnosis and tailored therapy. To aid memory retention and clinical utility, this article introduces the vibrant mnemonic: “Very RICH BAD MAN RAPS”, which neatly encapsulates the major causes of transverse myelitis.
What is Transverse Myelitis?
The term “transverse” refers to the inflammation extending across the width of the spinal cord, while “myelitis” refers to inflammation of the spinal cord itself.
This inflammation disrupts:
- Ascending sensory pathways
- Descending motor tracts
- Autonomic fibers regulating bowel and bladder
It can be monophasic or recurrent, and may evolve into neuromyelitis optica spectrum disorder (NMOSD) or multiple sclerosis (MS) in some cases.
Mnemonic: Very RICH BAD MAN RAPS
Each letter stands for a specific cause, grouped under a colorful and memorable phrase:
| Mnemonic | Cause |
|---|---|
| V | Vasculitis |
| R | Rabies (Post-vaccinal) |
| I | Idiopathic |
| C | Chemotherapeutic agents |
| H | Heroin abuse |
| B | Behçet’s disease |
| A | Acute demyelinating encephalomyelitis (ADEM) |
| D | Drugs and toxins |
| M | Multiple sclerosis |
| A | Antiphospholipid syndrome |
| N | Neuromyelitis optica (NMO) |
| R | Rubella, EBV, Influenza, HIV, etc. (viral infections) |
| A | Aspergillus/fungal/para-infectious |
| P | Paraneoplastic syndromes |
| S | Sulphasalazine/Sarcoidosis |
Let’s analyze each of these causes in depth.
V – Vasculitis
Vasculitis refers to inflammation of blood vessels supplying the spinal cord. Types include:
- Systemic lupus erythematosus (SLE)
- Polyarteritis nodosa (PAN)
- Granulomatosis with polyangiitis
These can cause ischemia and infarction of spinal cord tissue, manifesting as:
- Sudden-onset weakness
- Sensory loss
- Sphincter dysfunction
R – Rabies (Post-vaccinal)
Although rare, post-rabies vaccination transverse myelitis has been observed, especially with older formulations of nerve tissue vaccines.
Mechanism: Autoimmune cross-reactivity leading to central nervous system inflammation.
Modern cell-culture vaccines have largely reduced this risk.
I – Idiopathic
In many cases, no cause is identified even after extensive workup—this is termed idiopathic transverse myelitis.
It often follows:
- A viral illness
- Presents with a monophasic course
- May or may not recur
Idiopathic cases are usually treated with high-dose steroids and monitored for evolution into MS or NMOSD.
C – Chemotherapeutic Agents
Certain chemotherapeutic drugs have neurotoxic potential. For example:
- Methotrexate (especially intrathecal)
- Cytarabine
- Cisplatin
Mechanism: Direct damage to spinal cord neurons or glial cells.
Symptoms usually emerge days to weeks after administration.
H – Heroin Abuse
Intravenous drug users are at risk of transverse myelitis due to:
- Direct neurotoxic effects
- Contaminants or adulterants
- Infections leading to para-infectious inflammation
Clinical features in heroin-associated myelitis may mimic spinal cord infarction or abscess, making imaging essential.
B – Behçet’s Disease
Behçet’s is a multisystem vasculitis marked by:
- Oral and genital ulcers
- Uveitis
- CNS involvement, including transverse myelitis
Neurological Behçet’s (neuro-Behçet) can affect brainstem, spinal cord, and cerebral venous sinuses.
MRI may show longitudinal cord lesions.
A – Acute Disseminated Encephalomyelitis (ADEM)
ADEM is an autoimmune demyelinating disease, typically seen in children and young adults post-infection or vaccination.
Features include:
- Polyfocal neurological deficits
- Altered consciousness
- Often includes transverse myelitis as part of broader CNS demyelination
It is typically monophasic and steroid-responsive.
D – Drugs and Toxins
Other than chemotherapy, many drugs may contribute to transverse myelitis:
| Drug / Toxin | Mechanism |
|---|---|
| Isoniazid | Hypersensitivity |
| TNF-α inhibitors | Autoimmune demyelination |
| Lead, arsenic | Neurotoxic |
Discontinuation and supportive care are often needed.
M – Multiple Sclerosis (MS)
MS is one of the most common causes of demyelinating transverse myelitis.
- Usually presents with partial transverse myelitis (not involving entire cross-section)
- Often shows asymmetric lesions
- Diagnosed via MRI brain + spine, CSF analysis
It often coexists with optic neuritis, diplopia, or cerebellar symptoms.
A – Antiphospholipid Syndrome (APS)
APS is a prothrombotic autoimmune disorder that can cause:
- Spinal cord infarction
- Venous sinus thrombosis
- Recurrent miscarriages, livedo reticularis
It is associated with SLE or occurs in isolation. Diagnosis: Antiphospholipid antibodies (aCL, β2GP1, lupus anticoagulant).
N – Neuromyelitis Optica (NMO)
NMO, now recognized as neuromyelitis optica spectrum disorder (NMOSD), features:
- Longitudinally extensive transverse myelitis (LETM) – spans ≥3 vertebral segments
- Optic neuritis – severe and bilateral
- Anti-AQP4 antibodies (specific for NMO)
Treatment differs from MS; immunosuppression (e.g., rituximab) is preferred over interferons.
R – Rubella, EBV, Influenza, HIV, etc.
Numerous viral infections can trigger transverse myelitis, including:
- Rubella
- Epstein-Barr virus (EBV)
- Influenza
- Herpes simplex virus
- HIV
Mechanisms include direct infection, molecular mimicry, or immune activation. Viral myelitis tends to present acutely.
A – Aspergillus / Fungal / Para-Infectious Causes
Fungal infections like aspergillosis can reach the spinal cord via:
- Hematogenous spread
- In immunocompromised individuals (e.g., transplant patients, HIV)
Para-infectious causes refer to immune reactions following common infections (e.g., Mycoplasma, CMV).
P – Paraneoplastic Syndromes
Paraneoplastic transverse myelitis is a remote effect of malignancy, not due to tumor invasion.
Most commonly seen in:
- Small cell lung cancer
- Breast cancer
- Lymphoma
Often associated with anti-Hu, anti-Yo, or CRMP5 antibodies. Prognosis depends on underlying malignancy.
S – Sulphasalazine / Sarcoidosis
Sulphasalazine, used for IBD and arthritis, can rarely cause demyelination.
Sarcoidosis is a granulomatous disease that can involve the spinal cord, leading to:
- Chronic progressive myelopathy
- Imaging may show enhancing intramedullary lesions
Serum ACE levels, chest imaging, and biopsy may assist in diagnosis.
Clinical Features of Transverse Myelitis
Symptoms typically develop over hours to days and include:
| Symptom Category | Manifestation |
|---|---|
| Motor | Weakness (flaccid initially, later spastic), often bilateral |
| Sensory | Numbness, tingling, sensory level on the trunk |
| Autonomic | Bladder/bowel dysfunction, urinary retention or incontinence |
| Pain | Back pain or radicular limb pain |
Lesions often affect thoracic spinal cord, but any level can be involved.
Diagnostic Approach
1. MRI Spine (with contrast)
- Shows inflammatory lesions, rule out compressive causes
- Helps differentiate from MS or NMOSD
2. CSF Analysis
- Elevated WBCs, proteins, sometimes oligoclonal bands
3. Serologic Tests
- AQP4-IgG for NMOSD
- ANA, dsDNA, antiphospholipid antibodies
- Viral PCRs
5. Electrophysiology
- Somatosensory evoked potentials (SSEPs)
- Rule out peripheral neuropathy
Treatment Strategies
| Phase | Management |
|---|---|
| Acute | High-dose IV methylprednisolone (1g/day for 3–5 days) |
| Plasma exchange or IVIG if steroid-refractory | |
| Chronic/Long-term | Treat underlying cause (MS, NMOSD, autoimmune disease) |
| Immunosuppressants: Rituximab, Mycophenolate, Cyclophosphamide | |
| Supportive | Bladder training, physiotherapy, DVT prophylaxis |
Prognosis
- Mild to moderate cases may show partial or full recovery within weeks
- Severe cases (especially with complete motor loss) have poor prognosis
- Predictors of poor outcome: Rapid onset, spinal shock, absent recovery in 3 months
Early treatment is crucial to minimize permanent disability.
Summary Table: Very RICH BAD MAN RAPS
| Mnemonic | Etiology |
|---|---|
| V | Vasculitis |
| R | Rabies (post-vaccine) |
| I | Idiopathic |
| C | Chemotherapy-induced |
| H | Heroin abuse |
| B | Behçet’s disease |
| A | ADEM |
| D | Drugs/Toxins |
| M | Multiple sclerosis |
| A | Antiphospholipid syndrome |
| N | Neuromyelitis optica |
| R | Rubella, EBV, Influenza, HIV |
| A | Aspergillus/Fungal/Para-infectious |
| P | Paraneoplastic |
| S | Sulphasalazine / Sarcoidosis |
Frequently Asked Questions (FAQs)
Q1: What is the most common presenting symptom of transverse myelitis?
A: Sudden-onset bilateral lower limb weakness with a sensory level and bladder involvement.
Q2: How is NMOSD different from MS in transverse myelitis?
A: NMOSD has longitudinally extensive lesions (≥3 vertebral segments) and AQP4 antibodies, while MS has short segment lesions and brain involvement.
Q3: Can transverse myelitis be reversed?
A: Yes, especially with early steroid treatment. However, severe cases may lead to lasting deficits.
Q4: Is transverse myelitis contagious?
A: No. However, it may be triggered by infectious agents or vaccines.
Q5: What is the risk of recurrence?
A: Higher in cases secondary to NMOSD, MS, or autoimmune diseases. Idiopathic cases usually have a single episode.
