Spinal Cord Injuries

SCI Basics & Anatomy - Cord Under Siege

• Etiology:
  • Trauma (common): RTA, falls, violence.
  • Non-traumatic: Vascular, tumors, infections, degenerative.
• Cord Structure:
  • Meninges: Dura, Arachnoid, Pia.
  • Grey matter (central H-shape): Neuronal bodies.
  • White matter (peripheral): Tracts.
    • Ascending: Dorsal columns (proprioception, vibration, fine touch), Spinothalamic (pain, temp).
    • Descending: Corticospinal (motor).
• Vascular Supply:
  • Anterior Spinal Artery (ASA): Anterior 2/3.
  • Posterior Spinal Arteries (PSAs): Posterior 1/3.
• Key Concepts:
  • Spinal Shock: Transient reflex loss below injury.
  • Neurogenic Shock: Hypotension, bradycardia (injury ≥T6).

⭐ Vertebral level often doesn't correspond to spinal cord segment level, especially in lower spine (e.g., L1 vertebra injury can affect S1-S5 cord segments).

SCI Classification & Syndromes - Code Red Cord

• ASIA Impairment Scale (AIS):

  • A: Complete. No S4-S5 motor/sensory.
  • B: Sensory Incomplete. Sensory preserved below neurological level (NL) & S4-S5; no motor.
  • C: Motor Incomplete. Motor preserved below NL; >half key muscles <3.
  • D: Motor Incomplete. Motor preserved below NL; ≥half key muscles ≥3.
  • E: Normal.

• Key SCI Syndromes:

Clinical Picture & Diagnosis - Spotting the Damage

• Initial: ABCDEs. Neuro exam (motor, sensory, reflexes). ASIA Scale.
• Spinal Shock: Temp. reflex/sensorimotor loss below injury. Flaccid paralysis, areflexia, absent BCR. BCR return ends shock.
• Neurogenic Shock (SCI ≥T6): Sympathetic loss → vagal. Hypotension (SBP <90 mmHg), bradycardia, poikilothermia. ⚠️ Vs. hypovolemic.
• Table: Shock Types

  Feature	Spinal	Neurogenic (≥T6)
  Cause	Reflex loss	Sympathetic loss
  BP	Norm/Var	↓ Hypotension
  HR	Norm/Var	↓ Bradycardia
  Reflexes	Absent	Unaffected

• Autonomic Dysreflexia (SCI ≥T6, post-shock): Trigger: noxious stimuli (full bladder). Sudden HTN (↑SBP 20-40 mmHg), headache, bradycardia, sweating above.
  • ⭐ > Autonomic dysreflexia is a medical emergency in patients with SCI at or above T6, characterized by paroxysmal hypertension, bradycardia, and headache, often triggered by bladder or bowel distension.
• Diagnosis: Clinical (ASIA). Imaging: X-ray, CT; MRI (cord std).

SCI Management & Complications - Road to Recovery

Acute Management:

• Medical:

  ⭐ While controversial and not universally recommended, the NASCIS II protocol for methylprednisolone (bolus 30 mg/kg IV over 15 min, then 5.4 mg/kg/hr for 23 hrs if started within 3-8 hrs of injury) is a frequently tested topic.

  • Hemodynamic support (MAP >85-90 mmHg).
  • DVT/Stress ulcer prophylaxis.
• Surgical: Decompression, stabilization if indicated.
• Complications:
  • Neurogenic Shock (↓BP, ↓HR).
  • Spinal Shock (transient flaccid paralysis).
  • Autonomic Dysreflexia (≥T6): noxious stimuli → HTN, headache. Rx: sit up, remove trigger.
  • Pressure Sores.
  • Respiratory, DVT/PE.
• Rehab: Multidisciplinary team approach for functional recovery and quality of life improvement.

High‑Yield Points - ⚡ Biggest Takeaways

• ASIA Scale is vital for SCI classification and predicting prognosis.
• Distinguish spinal shock (transient areflexia) from neurogenic shock (hypotension, bradycardia).
• Central cord syndrome: Most common incomplete SCI; upper limbs affected more than lower.
• Anterior cord syndrome: Worst prognosis; motor, pain, temperature loss below lesion.
• Brown-Séquard syndrome: Ipsilateral motor/proprioception loss, contralateral pain/temperature loss.
• Autonomic dysreflexia (lesions above T6): Medical emergency; triggered by noxious stimuli below injury.
• Sacral sparing indicates an incomplete lesion and a better chance of recovery.