Spinal Cord Injury Overview

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Questions and Answers

What is the initial vascular response in the spinal cord shortly after an injury?

Petechial haemorrhages are observed in the central grey matter.

Describe the changes that occur in the spinal cord 1 to 2 hours post-injury.

Red blood cells, fluid, and leukocytes infiltrate the grey matter, leading to vascular stasis and endothelial damage.

After 4 hours post-injury, what percentage of the spinal cord grey matter is affected by coagulation necrosis?

Coagulation necrosis affects up to 40% of the grey matter and adjacent white matter.

What characterizes spinal shock following a spinal cord injury?

Spinal shock presents with hypotension, bradycardia, and warm, dry extremities. Signup and view all the answers

How long does spinal shock typically last?

Spinal shock typically lasts 7 to 10 days. Signup and view all the answers

What indicates the resolution of spinal shock?

Indicators include spasticity, reflex bladder emptying, and hyperreflexia. Signup and view all the answers

What is neurogenic shock and how is it caused?

Neurogenic shock is caused by loss of autonomic regulation from brain to sympathetic nervous system, often due to injuries above T6-T7. Signup and view all the answers

What occurs 24 hours post-injury to the spinal cord tissue?

The spinal cord consists mostly of necrotic tissue with aggregated red blood cells and minimal recognizable white matter. Signup and view all the answers

What are the primary age and gender risk factors associated with spinal cord injury?

Individuals aged 16-30 are most at risk, and males are affected four times more than females. Signup and view all the answers

Describe the difference between complete and incomplete spinal cord injuries.

A complete spinal cord injury results in total loss of function and sensation below the injury site, while an incomplete injury preserves some function. Signup and view all the answers

What is the significance of the neurological level in assessing spinal cord injuries?

The neurological level indicates the lowest segment of the spinal cord with normal motor and sensory function on both sides of the body. Signup and view all the answers

What are the four main classifications of spinal cord injuries based on location?

Spinal cord injuries can be classified as cervical, thoracic, lumbar, or sacral. Signup and view all the answers

Explain how hyperflexion injuries occur and give an example.

Hyperflexion injuries occur when the head and neck are forcibly bent forward and then snapped back, such as in a head-on collision. Signup and view all the answers

Identify the scale used to assess muscle strength in spinal cord injury patients.

Muscle strength is scored on a scale of 0-5, where 0 indicates no muscle contraction and 5 indicates normal strength. Signup and view all the answers

What role does alcohol play in spinal cord injuries, especially in motor vehicle accidents?

Alcohol is a contributing factor in many motor vehicle accidents that result in spinal cord injuries. Signup and view all the answers

How does rotational movement cause spinal cord injuries? Provide an example.

Rotational movement injuries occur due to extreme lateral flexion or twisting of the head and neck, like in a motorcycle accident. Signup and view all the answers

Study Notes

Spinal Cord Injury

Injury to the spinal cord and vertebrae that can cause temporary or permanent changes in its function.
The cause of these injuries are often associated with motor vehicle accidents, falls, sporting accidents and direct blows to the back and vertebrae.
Risk factors include age, gender, and alcohol use.
- More than 50% of spinal cord injuries occur in people aged 16-30 years old.
- Older people experience the most fall-related injuries.
- Men are four times more affected than women.
- Alcohol use is a factor in many motor vehicle accidents resulting in a spinal cord injury.

Classification and Level of Injury

The part of the spinal cord damaged corresponds to the spinal nerves at that level and below the damaged area.
Injuries can be classified by the vertebral level at which they occur:
- Cervical (C1-C8)
- Thoracic (T1-T12)
- Lumbar (L1-L5)
- Sacral (S1-S5)
Quadriplegia/Tetraplegia, paralysis of all four extremities, occurs when the cervical spinal cord is involved.
Paraplegia, paralysis of the lower body, occurs when the thoracic or lumbar spinal cord is damaged.
Injuries are classified by the level of the spinal cord affected:
- Skeletal level: Injury at the vertebral level, where there is the most damage to the vertebral bones and ligaments.
- Neurological level: Refers to the lowest segment of the spinal cord with normal sensory and motor function.
- Complete: Total loss of sensation and muscle function below the level of injury.
- Incomplete: Preservation of motor or sensory function below the level of injury.
Sensory impairment is based on neurological responses such as touch and pinprick sensations.
Motor impairment is graded on a scale of 0-5 (0 being no contraction, 5 being normal strength).

Major Mechanisms of Injury

Hyperextension: Excessive posterior movement of the head.
- Often caused by rear-end collisions or falls on the chin.
Hyperflexion: Head and neck are forcibly flexed then snapped backward into forced hyperextension.
- Often seen in sudden deceleration events such as head-on collisions, causing whiplash.
Compression movement: Extreme vertical movement, causing vertebrae to shatter or burst.
- Caused by diving into shallow water or a fall greater than 10 to 20 feet onto the legs.
Rotational movement: Extreme lateral flexion or twisting of the head and neck.
- Examples are rollovers or motorcycle accidents.
Distraction: Excessive force applied to the spinal column and cord.
- This can be caused by a child wearing a shoulder belt around their neck.
Penetrating injury: Direct contact with the spinal cord by a knife or bullet.

Pathophysiology

Spinal cord injury progresses through several stages:
- Shortly after the injury:
  - Petechial hemorrhages are observed in the central grey matter of the spinal cord.
- 1 to 2 hours post-injury: -Red blood cells, fluid, and polymorphonuclear leukocytes infiltrate the grey matter.
  - This leads to vascular stasis and endothelial damage.
  - Haemorrhage, oedema, and metabolic changes cause ischemia, leading to necrosis.
  - Hypoxia worsens as oxygen levels drop below what the spinal cord requires. This results in increased lactate and toxic levels of norepinephrine.
  - Norepinephrine causes vasospasm, furthering hypoxia and necrosis.
- 4 hours post-injury: Coagulation necrosis affects up to 40% of the grey matter and adjacent white matter.
- 24 hours post-injury: The spinal cord becomes mostly necrotic tissue, with aggregated red blood cells and minimal recognisable white matter.
  - Oedema spreads above and below the injury site, increasing ischemic damage. The outcome mimics mechanical severance of the cord.
- 48 hours post injury: Haemorrhagic necrosis completes the lesion, and nerve function at the level of the injury is irreversibly lost.

Spinal Shock

Mechanism: After spinal cord injury, spinal shock occurs when the entire cord below the level of injury temporarily ceases to function.
Characteristics:
- Hypotension
- Bradycardia
- Warm, dry extremities
Onset: Occurs immediately after the injury, resulting in a sudden loss of all motor and sensory function below the injury site.
Effects:
- Loss of sympathetic innervation leads to peripheral vasodilation, venous pooling, and decreased cardiac output, particularly seen in cervical or high thoracic injuries.
Duration: Typically lasts 7 to 10 days.
Resolution:
- Indicators that spinal shock has ended include spasticity, reflex bladder emptying, and hyperreflexia.
- Once spinal shock resolves, rehabilitation can begin.

Neurogenic Shock

Cause: Caused by the loss of autonomic regulation from the brain to the sympathetic nervous system, often due to injuries above T6-T7.
Mechanism: The loss of sympathetic control results in a failure to regulate blood pressure, causing hypotension and bradycardia (different from hypovolemic shock).
Different from Hypovolemic Shock

Types of Spinal Cord Injuries

Concussion: Shaking of the spinal cord, leading to temporary loss of function.
Incomplete: Some function is preserved below the level of the injury.
Complete: Total loss of function below the level of the injury.
Central Cord Syndrome: Injury mainly to the central portion of the spinal cord, affecting the arms more than the legs.
Anterior Cord Syndrome: Injury to the front part of the spinal cord, affecting motor function and pain and temperature sensation.
Brown-Séquard Syndrome: Injury to half of the spinal cord, affecting motor function and sensation on one side of the body.
Cauda Equina: Injury to the nerves of the cauda equina, a bundle of nerves at the end of the spinal cord, affecting bladder and bowel control, and sensation in the legs and feet.

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Description

This quiz covers the causes, risk factors, and classification of spinal cord injuries. Learn about the types of injuries based on the vertebral level and their impact on motor function. Test your knowledge of spinal cord health and injury prevention.