Write a short note on Spinal Shock & Neurogenic Shock.
Two Distinct Entities
‘Shock’ in spinal injury refers to two entirely different phenomena that are frequently confused. Spinal shock is a neurological phenomenon (loss of cord function), whereas neurogenic shock is a circulatory phenomenon (a form of distributive shock). They may coexist but must be distinguished.
Spinal Shock
Spinal shock is the transient loss of all spinal cord functions below the level of injury immediately after trauma — flaccid paralysis, areflexia, and loss of sensation and autonomic tone. It is temporary; recovery of reflexes begins within 24–48 hours, signalled by return of the bulbocavernosus reflex. The completeness of a cord injury (and hence prognosis) can only be judged after spinal shock has resolved.
Neurogenic Shock
Neurogenic shock occurs with injuries above T6, where loss of sympathetic outflow leaves unopposed vagal tone. The result is hypotension with bradycardia and warm, vasodilated peripheries — a combination that distinguishes it from hypovolaemic shock (which causes tachycardia and cold peripheries).
| Feature | Spinal shock | Neurogenic shock |
|---|---|---|
| Nature | Neurological (cord) | Circulatory (haemodynamic) |
| Findings | Flaccidity, areflexia | Hypotension + bradycardia |
| Level | Any complete cord injury | Lesion above T6 |
| Recovery marker | Bulbocavernosus reflex returns | Resolves with sympathetic recovery |
| Treatment | Supportive; await resolution | Fluids, vasopressors, atropine |
DANGER / REMEMBER
In a trauma patient, always assume hypotension is due to haemorrhage until proven otherwise. Diagnose neurogenic shock only after excluding bleeding; the tell-tale sign is hypotension with bradycardia rather than tachycardia.
WHY the Distinction Matters
Confusing the two is dangerous. Treating neurogenic shock as pure hypovolaemia leads to over-transfusion and pulmonary oedema, while attributing a fall in blood pressure to the cord injury can cause a fatal missed haemorrhage. Equally, prognosticating a cord injury as ‘complete’ during the phase of spinal shock is invalid, because reflexes and some function may yet return once spinal shock resolves. The safe rule is: resuscitate for haemorrhage first, and judge cord completeness only after spinal shock has passed.
Bradycardia with hypotension distinguishes neurogenic from hypovolaemic shock.
KEY POINT
Key points TO remember
- Spinal shock = neurological (flaccid, areflexic); neurogenic shock = circulatory.
- Bulbocavernosus reflex return marks the end of spinal shock.
- Neurogenic shock (lesion >T6): hypotension + bradycardia + warm peripheries.
- Exclude haemorrhage first; treat neurogenic shock with fluids, vasopressors, atropine.
EXAM TIP
Sources: Maheshwari's Essential Orthopaedics; Apley & Solomon's System of Orthopaedics and Trauma; AO Principles of Fracture Management.
All questions in Spine & Pelvis
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- Q3Describe Spinal Cord Injury — Syndromes & Management in detail. ★
- Q4Define Cervical Spine Injuries. Describe its investigations, management and complications. ★
- Q5Define Acetabular Fractures. Describe its classification, clinical features, investigations and management. ★
- SN1Write a short note on Spinal Shock & Neurogenic Shock. ★
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- SN6Describe Pelvic Haemorrhage Control & the Pelvic Binder in detail.
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