Transverse Myelitis

1. THE 2-MINUTE PHYSIOLOGY (Rapid Pathophysiology)

• Definition & Anatomy: Acute transverse myelitis (TM) is a rare, devastating, non-compressive inflammatory disorder of the spinal cord that involves a complete or partial section of the cord. Symmetrical gray and white matter spinal lesions most commonly localize to the thoracic cord, followed by the cervical and lumbosacral segments.
• Immune-Mediated Breakdown: Pathophysiologically, the process is driven by immune-mediated demyelination and axonal damage of the central nervous system. This cascade results in severe inflammation of focal spinal segments. In up to 30% of cases, the syndrome is postinfectious, triggered by viral, gastrointestinal, or systemic illnesses, post-vaccination, or it arises as an initial manifestation of systemic autoimmune conditions (such as systemic lupus erythematosus, Sjögren’s syndrome, eosinophilic granulomatosis with polyangiitis, sarcoidosis, and neurosarcoidosis), malignancies, or most commonly, Multiple Sclerosis (MS).
• Mechanics of Dysfunction: The localized inflammatory swelling disrupts spinal pathways, resulting in a defined transverse level of sensory impairment, flaccid or spastic motor paralysis, and autonomic dysfunction (including fecal and urinary retention or incontinence).

2. THE BEDSIDE ACTION PLAN (Rapid ER Management)

• Airway and Ventilatory Assessment: Immediately evaluate airway patency, the ability to clear secretions, and respiratory mechanics. Expect rapid respiratory decompensation if symptom delineation suggests a lesion at the level of the cervical spine or medulla. Secure the airway with endotracheal intubation if the patient is unable to protect their airway, exhibits respiratory acidosis, or if interfacility transport is anticipated.
• Rapid Sequence Intubation (RSI) Contraindication: Succinylcholine must be avoided during RSI due to the severe risk of catastrophic hyperkalemia associated with acute lower motor neuron or spinal cord pathology. Use rocuronium as the preferred paralytic agent.
• Autonomic Instability & Vasoactive Titration: Monitor vital signs closely for autonomic dysreflexia, marked dysrhythmias, and labile blood pressure (particularly if the lesion is at the T6 level or above). Address autonomic instability with fluids and titrable vasoactive medications:
• BP Management Protocol: Start with low doses (e.g., 250 µg/kg bolus, followed by 25 µg/kg/min, then slowly titrated; titrate the infusion by 25–50 µg/kg/min every 5 minutes until the goal mean arterial pressure is achieved, up to a maximum rate of 300 µg/kg/min). Avoid over-treating or causing sudden fluctuations in blood pressure.
• Hyperacute Immunosuppressive Therapy: Once compressive lesions are ruled out, initiate high-dose intravenous corticosteroid therapy immediately in the ED:
• Regimen 1: Methylprednisolone 30 mg/kg IV (maximum dose 1,000 mg daily) for 3 to 5 days.
• Regimen 2: Dexamethasone 120–200 mg IV.
• Refractory Immunomodulation: Coordinate early with neurology for therapeutic plasma exchange (PE) (typically 5 to 7 exchanges over 2 weeks) for patients with significant motor paralysis or those who fail to improve clinically or radiographically after 3 to 5 days of high-dose steroids. Dialysis catheter central venous access is preferred. For aggressive, refractory disease, Cyclophosphamide may be utilized, showing the highest efficacy in patients with concomitant SLE.
• Neurogenic Bladder Decompression: Perform immediate bladder ultrasound or straight catheterization to assess for urinary retention. If post-void residual (PVR) is elevated (>100–200 mL), place a urinary catheter to prevent detrusor injury.

3. THE DIAGNOSTIC GRID (Differential Diagnosis & Workup)

Top "Can't-Miss" Mimics

1. Epidural Compression Syndrome (Compressive Myelopathy): Spinal cord compression secondary to a spinal epidural abscess, spinal epidural hematoma, metastatic vertebral tumor, or central disc herniation. Differentiated by emergent MRI showing direct mechanical compression of the cord.
2. Guillain-Barré Syndrome (GBS): Symmetrical ascending weakness and flaccid paralysis with loss of deep tendon reflexes. Differentiated by a lack of a sharp sensory level, spared bowel/bladder sphincter tone, and characteristic cerebrospinal fluid (CSF) findings.
3. Spinal Cord Ischemia or Infarction: Acute onset of anterior cord syndrome (symmetrical motor loss and pain/temperature loss below the lesion, with preserved proprioception and vibration).
4. Hypokalemic Periodic Paralysis: Rapidly progressive, generalized proximal motor paralysis with lost reflexes. Sensation remains intact, bowel/bladder function is spared, and weakness rapidly resolves with potassium repletion.

Prioritized Workup Strategy

• Bedside POC Glucose: Checked immediately at triage to rule out hypoglycemia as a stroke/myelopathy mimic.
• Urgent Neuroimaging (Gold Standard): Contrast-enhanced Magnetic Resonance Imaging (MRI) of the entire spine is the diagnostic test of choice to rule out compressive lesions and identify spinal cord inflammation.
• Myelography alternative: If the patient has true contraindications to MRI, order CT myelography of the entire spine.
• Lumbar Puncture (CSF Studies): Indicated to assist in the diagnosis. Spinal fluid typically demonstrates lymphocytosis (elevated WBCs) and elevated protein. This does not need to be done urgently in the ED and should follow neuroimaging.
• Basic Labs: CBC (screen for infection), CMP (evaluate electrolytes and renal function), and ESR/CRP.

4. THE VISUAL BOARD (ECG / POCUS / Imaging)

Standard ECG Visual Checklist

• Rhythm Screening: Monitor for bradycardia or dysrhythmias associated with autonomic instability or high-level spinal cord injury (T6 or above).

Point-of-Care Ultrasound (POCUS) Findings

• Bladder Residual Volume: Perform bedside bladder scanning to screen for neurogenic bladder retention. A post-void residual volume greater than 100 to 200 mL carries a 90% sensitivity for cauda equina or neurogenic bladder pathology.

Neuroimaging Visual Checklist

• Standard non-contrast spinal CT limitations: Dry CT head and spine scans are normal or non-specific and are insufficient to rule out transverse myelitis.
• MRI of the Spine (T2-Weighted sagittal and axial sequences):
• Look for focal T2 hyperintensity within the gray and white matter of the spinal cord (most commonly thoracic).
• Assess for active post-gadolinium contrast enhancement, which highlights active blood-spinal cord barrier breakdown.
• The "Imaging Lag" Pitfall: MRI findings can lag behind the clinical presentation early in the disease process. If definite cord signs exist on physical exam but the initial MRI is normal, transverse myelitis remains a primary working diagnosis.

5. THE SCORING MATRIX (Risk Stratification & Guidelines)

NEXUS Criteria and Canadian C-Spine Rule

• These validated decision instruments are used to clinically clear the cervical spine in trauma patients. They cannot be applied to non-trauma cases, patients with GCS <15, or patients presenting with acute paralysis or focal neurologic deficits.

MRI-Based Lesion Classifications

• Acute Partial Transverse Myelitis: Characterized by an asymmetrical spinal cord lesion spanning less than 3 vertebral segments on MRI.
• Acute Complete Transverse Myelitis: Characterized by complete or near-complete symmetrical clinical deficits spanning less than 3 vertebral segments on MRI.
• Longitudinally Extensive Transverse Myelitis (LETM): Characterized by a spinal cord lesion spanning over 3 vertebral segments on MRI (classically associated with systemic autoimmune diseases like SLE).

6. THE DANGER ZONE (Pitfalls & Critical Actions)

Deadly Cognitive Traps & Trainee Pitfalls

• The "Normal MRI" Dismissal: Prematurely ruling out transverse myelitis because the initial spinal MRI is normal. MRI findings frequently lag behind clinical deficits early in the disease process.
• The Succinylcholine Hyperkalemia Disaster: Administering succinylcholine during RSI in a patient with acute transverse myelitis or flaccid paralysis. This can precipitate lethal hyperkalemia.
• Withholding Steroids for LP: Delaying the initiation of high-dose corticosteroids in the ED while waiting to perform a lumbar puncture or wait for CSF results.
• Anchoring on Trauma: Attributing a patient’s motor deficits solely to a fall or motor vehicle collision, when the trauma was actually secondary to a sudden fall caused by transverse myelitis weakness.
• Missed Autonomic Dysreflexia: Failing to recognize that severe hypertension, diaphoresis, and bradycardia in a patient with a prior high cord lesion (above T6) represents an autonomic storm triggered by a noxious stimulus like a blocked bladder catheter or fecal impaction.

Mandated Board-Exam Critical Actions

• Document deep tendon reflexes on all patients presenting with weakness before administering sedatives or paralytics.
• Perform a meticulous skin exposure exam to rule out other causes of ascending paralysis, specifically checking for a tick to exclude tick paralysis.
• Assess and document rectal tone and saddle sensation in all patients presenting with acute back pain and motor deficits.
• Assess respiratory function parameters (RR, forced expiratory volume, and negative inspiratory force) to catch impending ventilatory failure.

7. MCQ MASTERCLASS (Written Exam Tips)

High-Yield Exam "Buzzwords" and Associations

• "Bimodal Peak Age": Unlike GCA or stroke which occur in older adults, TM classically features bimodal peaks between 10 to 19 years and 30 to 39 years.
• **"Symmetric Weakness":**Symmetric weakness is the most common presentation of transverse myelitis. Sparing of the upper extremities is common unless cervical cord involvement is present.
• "Defined Neurologic Level": Unlike peripheral neuropathies, TM has a defined transverse sensory level of impairment accompanied by hyperreflexia and positive Babinski signs.
• "Autonomic Dysreflexia": Classically presents in patients with prior lesions above T6 as severe hypertension (e.g., BP 270/130 mm Hg), bradycardia, headache, and diaphoresis. Bladder distention is the most common trigger. Immediate treatment is BP management with nitrates and urinary catheterization.
• "Prognostic Expectation": Written boards frequently ask about long-term recovery. Reassure or select that roughly one-third of TM patients have a good outcome, one-third have moderate disability, and one-third have severe disability.

8. THE BOARDROOM SCRIPT (OSCE & Oral Board Tips)

Triage and Stabilization Script

• "This patient presents with acute progressive bilateral motor weakness, back pain, and sensory deficits, raising strong suspicion for acute transverse myelitis. I will place the patient in a monitored resuscitation bay and assess their airway and breathing immediately."*
• "If the patient displays signs of high cervical cord involvement, diaphragmatic breathing, or difficulty clearing secretions, I will prepare for endotracheal intubation. I will explicitly state to my team that succinylcholine is strictly avoided in this patient due to the risk of severe hyperkalemia in acute spinal cord disease; rocuronium is my paralytic of choice for RSI."*
• "I will obtain an immediate bedside point-of-care glucose to rapidly exclude hypoglycemia as a focal metabolic mimic."

Mandatory Physical Exam Phrasing

• "I will perform a detailed neurological examination. I am specifically checking deep tendon reflexes to look for hyperreflexia, and I am performing a rectal exam to document rectal tone."
• "I will perform a bedside bladder ultrasound to evaluate for neurogenic urinary retention."
• "I am performing a meticulous skin exposure exam to look for a tick to rule out tick paralysis, as well as any lupus or autoimmune-associated rashes."
• "I will determine the patient's defined transverse sensory level to pinpoint the spinal cord segment involved."

Diagnostics and Management Phrasing

• "To establish a rapid, definitive diagnosis, I will order an emergent contrast-enhanced MRI of the entire spine to rule out a compressive epidural lesion (such as an abscess, hematoma, or tumor) and confirm spinal cord inflammation. If MRI is absolutely contraindicated, I will proceed with a CT myelogram of the entire spine."
• "Once compressive pathology is ruled out on MRI, I will immediately initiate high-dose Methylprednisolone 30 mg/kg IV (maximum 1,000 mg daily) in the ED to treat transverse myelitis. I will not delay steroid therapy for a lumbar puncture. If the patient is refractory to steroids after 3 to 5 days or has profound motor paralysis, I will coordinate with neurology for therapeutic plasma exchange."

Disposition Phrasing

• "I will consult neurology. Because this patient has a devastating, progressive neurological deficit, I will admit them to the hospital. If they have any evidence of respiratory compromise based on negative inspiratory force, forced expiratory volume, or respiratory rate, I will admit them directly to the Intensive Care Unit (ICU) for continuous airway monitoring."