Brain & spinal cord trauma Flashcards
What is the definition of brain trauma?
- traumatic insult to brain
* producing physical, intellectual, emotional, social, vocational changes
What individuals are at risk of of brain trauma?
- 6months to 2yrs
- school-aged kids
- 15-35yr olds
- > 70yr olds
- men x 1.5
- high crime areas
What is blunt brain trauma?
- closed; nonmissile
- head strikes hard surface or fast object strikes head
- dura intact
- focal or diffuse injuries
What is open brain trauma?
- penetrating; missile
- injury breaks dura
- exposes cranial contents to environment
- primarily causes focal injuries
What are the causes of brain trauma?
- falls
- MVA
- moving objects or moving against stationary objects
- assault
- sports
- blasts (military)
What is the severity of brain trauma?
75-90% are not severe
What is the hallmark of severe brain injury?
loss of consciousness > 6hrs
List the types of focal brain injury?
- coup - directly below point of impact
- contre coup - opposite to site of impact
- coup-contracoup - both together
What can contusions cause?
- extradural (epidural) hemorrhage or hematoma
- subdural hematoma
- intracerebral hematoma
What is an extradural haematoma?
- 85% are from arterial bleeding
- 15% are from meningeal vein or dural sinus
- 90% are from skull fracture
- temporal fossa is most common site
- features: diminishing consciousness, nausea, vomiting, low HR, high BP, fixed dilated pupils
What is a subdural haematoma?
- counts for 10-20% of traumatic brain injury
- most from MVAs
- 50% are with fracture
- common with falls
- acute: 48hrs post trauma, often top of skull
- chronic: over wks or mnths, in older adults, alcohol abuse, chronic headache, tenderness at injury site
What is an intracerebral haemorrhage?
- mostly from MVA and falls
* acts as expanding mass -> increasing ICP -> compression -> oedema
List the types of diffuse brain injury?
- diffuse axonal injury (DAI)
* concussions
What is diffuse axonal injury?
- result of shaking (acceleration/deceleration)
* axonal damage due to shearing, tearing, stretching nerve fibers
Describe the concussion grades?
I - confusion, disorientation, momentary amnesia
II - momentary confusion and retrograde amnesia
III - confusion, retrograde and anterograde amnesia
IV - “classis concussion”
What are the characteristics of a grade IV concussion?
- disconnection of cerebral systems from brainstem and reticular activating system
- physiologic and neurologic dysfunction without substantial anatomic disruption
- lost consciousness (<6hrs)
- anterograde and retrograde amnesia
What is postconcussive syndrome?
- headache
- cognitive impairments
- psychogenic and somatic complaints
- cranial nerve signs and symptoms
What is the aetiology of spinal cord trauma?
- commonly from vertebral fractures
- traumatic compression, pulling, shearing forces
- most common C1,2,4-7, T1-L2 (most mobile and most canal occupied by spinal cord)
What are the mechanisms of spinal cord injury?
- hyper-extension
- hyperflexion
- axial compression
- flexion-rotation
List the stages of spinal cord trauma?
a. spinal shock
b. neurogenic shock
What is spinal shock?
- following trauma, short term
- spinal cord activity ceases below lesion
- sites lack continuous nervous discharges from brain
- complete loss of reflex function (skeletal, bladder, bowel, sexual, thermal, autonomic control)
- spinal cord not that damaged, it is from oedema
- partial recovery
What is neurogenic shock?
- loss of sympathetic outflow
* results in vasodilation, hypotension, bradycardia, hypothermia
What are the consequences of an L1 injury?
- paraplegia
* paralysis below the waist
What are the consequences of a T6 injury?
- paraplegia
* paralysis below the chest
What are the consequences of a C6 injury?
partial paralysis of hands and arms and lower body
What are the consequences a C4 injury?
- quadriplegia /tetraplegia
* complete paralysis below neck
What is autonomic hyperreflexia?
- also called dysreflexia
- massive, uncompensated cardiovascular response to stimulation of sympathetic nervous system
- stimulation of sensory receptors below the level of cord lesion
- months after spinal shock and healing -> scarred -> hypersensitive -> overreact to full bladder or full rectum -> reaction by high BP
Describe chemical and metabolic changes to the spinal cord in spinal cord trauma
- release of toxic excitatory amino acids
- accumulation of endogenous opiates
- lipid hydrolysis
- production of active metabolites
- local free radical release
- further ischemia -> vascular damage -> necrosis -> swelling
What is the difference between a concussion and a contusion?
Concussion:
• microscopic widespread axonal damage
• from shaking
• confusion or lost consciousness
Contusion:
• macroscopic damage
• bleeding due to localized trauma
• increases ICP
Why is head motion the principal causative mechanism of diffuse brain injury?
- coup-contrecoup
- A-P shearing of hemispheres damages corpus callosum
- punch to the jaw -> rotation force around brainstem -> lesion to reticular activating system -> K.O.
Compare UMN and LMN lesions?
UMN-lesion • in brain and spinal cord • spastic, keep muscle tone • reflex intact • damaged by stroke, brainstem lesions
LMN-lesion
• outside spinal cord
• flaccid, loose muscle tone, fasciculations
• no reflex, no strength
• from compression, broken bone, rapid overstretch, peripheral neuropathy
