Spinal cord injury

Question 1

How is spinal cord injury classified?

Answer 1

ASIA classification:
A: Complete - no motor or sensory function in S4-S5
B: Incomplete - no motor function preserved below level of lesion but sensory function intact
C: Incomplete - Some preservation of motor function. More than half of the key muscles have power <3
D: Incomplete - Some preservation of motor function. More than half of the key muscles have a motor function >2.
E: Normal - sensory and motor function normal

Tip: ASIA classification focuses predominantly on motor function. Presence of sensory function only differentiates between A and B.

Question 2

What spinal cord syndromes are you aware of?

Answer 2

Brown-Sequard syndrome: Ipsilateral loss of motor, fine touch and vibration sense. Contralateral loss of temperature and pain.

Anterior spinal cord syndrome: (Anterior spinal artery - supplies anterior 2/3 or cord). Bilateral loss of motor, pain and temperature. Proprioception and vibration intact.

Central cord syndrome:

• UMN signs in legs and mixed UMN/LMN signs in arms.
• Arms affected > than legs
• motor impairment > sensory
• Loss of pain and temperature in upper limbs
• proximal sparing

Complete transection of the cord: Loss of all motor and sensory level below the lesion.

Cauda equina: Perineal sensory impairment with loss of anal sphincter tone and bladder function. Asymmetric motor and sensory deficit. Knee and ankle jerks may be absent.

Conus medullaris: Absent ankle, present knee reflexes. Areflexic bladder, faecal incontinence.

Question 3

What is neurogenic shock?

Answer 3

• loss of vascular tone and associated hypotension (distributive shock)below the level of the lesion.
• bradycardia
• hypothermia
• results from loss of autonomic pathways (particularly cardiac sympathetic nerves (T2-T5)).

Question 4

What is spinal shock?

Answer 4

• loss of reflexes below the level of the lesion leading to flaccid areflexia.
• can take 3-6 weeks to recover
• spasticity and autonomic dysreflexia are common
• 50-80% of patients with lesions above T7 develop autonomic dysreflexia.

Question 5

What is autonomic dysreflexia

Answer 5

• in spinal injury patients (usually T6 and above):
• in response to stimulus below the level of the lesion the afferent stimulus (often pain, bladder, bowel) triggers a mass, sustained spinal sympathetic reflex below the lesion which isn’t moderated by central negative feedback.
• clinically this presents as profound hypertension with vagal mediated reflex bradycardia, headaches, sweating, flushing above the lesion. Pale and cold (vasoconstricted) below the lesion.
• may lead to seizures, stroke or cardiac arrest.

Management should in the first instance be preventative.
Management of hypertension can include PRN vasodilators or antihypertensives.

Question 6

What are the principles of initial management after acute spinal injury? What specific considerations need to be given to airway, breathing and circulation?

Answer 6

Initial management should follow an ABCDE approach.

Airway:

• low threshold for airway and ventilatory support, especially in cervical injuries.
• C5 and above likely to need intubation and ventilation
• intubation may be complicated by need for RSI and MILS
• avoid suxamethonium after 72 hrs

Breathing:

• May have additional thoracic or pulmonary injury.
• If LOC, may have aspirated.
• Likely to have impaired ventilation in cervical injuries and need urgent ventilatory support.
• may be easier to ventilate in supine position.

C:

• may have neurogenic shock and be cardiovascular unstable on induction
• CVS stability may be made worse by associated trauma/haemorrhage.
• have vasopressors to hand

Other considerations:

• VTE prophylaxis
• stress ulcer prophylaxis
• VAP bundles
• pressure areas
• avoidance of hypoxia, hypotension, and hypercarbia are crucial in the days after injury
• Imaging
• Neurosurgical discussion

Question 7

What factors determine prognosis after spinal cord injury?

Answer 7

1. Level of injury
2. Age of patient
3. Injury severity