Moderate And Severe Traumatic Brain Injury Flashcards
Lifetime cost of severe TBI per person
4 million
Annual cost of TBI
80 billion
Common causes of TBI
- MVC 20%
- Falls 28%
- Violence 11%
- Sport/recreation 10%
Closed head injury
External forces/objects hitting the head or hitting head hard enough to cause brain movement
- May see coup/contrecoup injury
Severe acceleration/deceleration
May cause injury without head strike
- Whiplash, shaken-baby syndrome
Blast injuries
Explosions resulting in fast moving pressure wave affecting skull and brain parenchyma
Penetrating injuries
Objects breaching skull cavity cause direct cellular and vascular damage
Contre-coup lesions
Results from a closed head injury when the skull comes to a stop then brain rebounds
Primary damage resulting from TBI
- Contusions
- Lacerations
- Epidural hematoma/hemorrhage
- Subdural hematoma
- Diffuse axonal injury
- Penetrating injuries
- Blast injuries
Brain contusions
Bruise within the brain, can occur in any region
Lacerations in the brain
Can occur in areas where the skull surface is irregular or to brain vasculature
- Can cause CSF leak if dura compromised
Epidural hematoma/hemorrhage in TBI
Tearing of meningeal vessels causes blood to collect between skull and dura, highly associated with skull fracture
Subdural hematoma
Result of tears to bridging veins, often due to acceleration/deceleration injury including falls
Diffuse axonal injury
Aka shearing injury, very common even in mild TBI
- Brain tissues that differ in structure/weight respond differently to acceleration/deceleration/rotation during trauma -> compromise to cellular membranes
Penetrating injuries
- Direct damage to tissues contacted
- High velocity objects ie. Bullets cause additional damage to remote areas of brain due to shock waves
Blast injuries
High pressure wave (overpressure) followed by low pressure wave (underpressure) -> compression/shearing of tissue, diffuse injury
Secondary damage following TBI
- Increased intracranial pressure
- Cerebral ischemia or hypoxia
- Electrolyte imbalance and acid/base balance
- Infection
- Seizures
Increased intracranial pressure following TBI
- Due to swelling or hematoma
- Skull cavity is fixed, increasing pressure can lead to tissue distortion ie. Midline shift or herniation
- Normal: 5-20 cm H2O
Cerebral ischemia or hypoxia following TBI
Results from compressed or ruptured vessels
Electrolyte imbalance and acid/base balance following TBI
Biochemical effects of neuron injury leading to cell death by necrosis or apoptosis
Infection following TBI
Can occur from open wounds or invasive monitoring
Seizures following TBI
Can occur due to tissue damage, pressure or scarring
Extra-ventricular drain
Catheter fed into lateral ventricle to monitor ICP and drain excess CSF
Autonomic nervous system and TBI
- Elevated sympathetic nervous system activity occurs following injury and can become sustained resulting in
- Increased HR/RR
- Increased BP
- Diaphoresis
- Excessive salivation, tearing
- Hyperthermia
- Dilated pupils
- Vomiting