head injury e woo. non-penetrating head injury most controversial issues are the deficits consistent...
TRANSCRIPT
HEAD INJURY
E Woo
Non-penetrating
head injury
Most controversial issues
• Are the deficits consistent with the injury? Malingering?
• Is there any pre-existing disease that may cause or contribute to his deficits?
• Should he be cared for at home?
• What is the remaining life expectancy?
• Mild injury→ mild deficits
• Severe injury → not necessarily severe residuals
Glasgow coma scale• Eye opening (E)• 4 Spontaneous • 3 To questions/command• 2 To pain• 1 Nil• Verbal response (V)• 5 Normal and oriented• 4 Confused speech• 3 Inappropriate speech• 2 Incomprehensible words• 1 Nil• Motor response (M)• 6 Normal and following commands• 5 Localize pain• 4 Withdrawal to pain• 3 Flexor posturing• 2 Extensor posturing• 1 No response
Severity of head injury
Mild GCS 14 to 15
Moderate GCS 10 to 13
Severe GCS ≤ 9
Post traumatic amnesia (PTA)
Mild less than 1 hour
Moderate 1 to 24 hours
Severe more than 24 hours
Retrograde amnesia
• how much the plaintiff can recall of what happened immediately before the accident
• variable, hence not a good guide for the severity of the head injury
• in general terms, for a mild injury, retrograde amnesia should be minimal
Fractures
• Vault - Linear
- Depressed
• Base
Sites of hemorrhage
Scalp hematomaIntracranial bleeding
- intracerebral- intraventricular- subarachnoid- extradural- subdural- combination
ICH
EDH
SDH
SDH
SAH
PARENCHYMAL DAMAGE
ContusionDiffuse axonal injury- shearing injury in acceleration/deceleration- no fracture or external wound- deep coma but normal intracranial
pressure- punctate lesions throughout the white
matter especially corpus callosum
Contusion
Contusion
Diffuse axonal Injury
Vascular damage
• Dissection of internal carotid artery
• Carotid-cavernous fistula
• Pseudo-aneurysm
Dissection
Carotid-cavernous Fistula
Pseudo-aneurysm
Treatment
Conservative
Surgical - evacuation of hematoma/contusion
- intracranial pressure monitoring
Late complications
• chronic subdural hematoma
• hydrocephalus
• CSF rhinorrhoea after skull-base fracture
Chronic subdural hematoma
• 4 to 6 weeks after accident, often mild injury
• Increasing headache
• Focal neurological deficits
• Burr-hole drainage
• Good prognosis (as distinct from acute subdural hematoma)
Hydrocephalus
- a few months after accident
- complicating subarachnoid/intraventricular
hemorrhage
- shunt operation (ventriculo-peritoneal)
- prognosis depends on shunt
Radiological investigations
• CT scan in acute phase
• MR scan in chronic phase
Outcome (Glasgow outcome scale)
• Normal ]
• Good recovery ] Independent
• Moderate disability ]
• Severe disability }
• Vegetative state } Dependent
• Death }
Residual disabilities• Headache• Dizziness• Vestibular dysfunction - vertigo
positional effect nystagmus• Memory loss - absent-mindedness loss of recent memory• Emotional disturbance - irritable anxious depressed• Frontal lobe dysfunction - apathy aggressiveness disinhibition, impulsivity suggestibility executive dysfunction frontal release signs
Sequelae
• Physical - cranial nerve deficits - hemiparesis
• Cognitive - dementia
• Emotional/Psychiatric
Post-concussional syndrome
• following upon mild/moderate head injury
• headache, nonspecific dizziness, tinnitus, insomnia, irritability, anxiety
• no structural pathology on imaging studies
• good prognosis
Persistent vegetative state
• Total lack of awareness of self or environment• No language function
(expression/comprehension)• Own sleep-wake cycles• No purposeful or behavioural response to visual,
auditory, tactile or noxious stimulus• Incontinence• Preserved brainstem reflexes
• May moan or groan• May even cry or shed tears• May blink• Jerky myoclonic movements (spinal origin)
Minimally conscious state
• Some sign of awareness
• Follow simple commands
• Gestural or verbal yes/no response
• Intelligible verbalization
• Purposeful behaviours contingent to relevant environmental stimuli (not reflexive)
Assessment
• starts before plaintiff walks in and continues through history taking
• Cognitive - mini-mental state examination (MMSE) • Physical:→eye movements→motor and sensory→reflex→co-ordination→gait
Malingering
• Cognitive - approximate answers - worsening MMSE over time• Physical - nonphysiological distribution of weakness
- Hoover’s sign - give-way weakness
- bizarre gait• Inconsistency of deficits• Incompatibility with site/extent of lesion• Discrepancy between history and examination• Handwriting
Impairment of the whole person
• Guides to the Evaluation of Permanent Impairment (American Medical Association)
• Based on ability to perform activities of daily living
• A numerical range for deficits in cognition and physical abilities
• No provision for headache
Loss of earning capacity
• Depends on occupation
Duration of sick leave
• Mild to moderate cases – recover over 6 to 12 months
• Severe cases – recover over 1 to 2 years
Life expectancy
• Adverse factors →severe cognitive dysfunction→swallowing difficulties (tube feeding)→physical deficits (immobility)→incontinence→Seizure
• Does good supportive care prolong survival?
Persistent vegetative state
• Markedly reduced survival
• 2 to 5 years
• Survival beyond 10 years unusual
Future medical treatment
• usually none after 1 to 2 years
• for those with severe deficits, e.g. bedbound or PVS, follow-up every 3 months
• tests
• medications
Post-traumatic epilepsy
• Risk factors
→severe injury (PTA > 24 hours)
→depressed skull fracture
→cerebral contusion
→acute subdural or intracerebral hematoma
→early epilepsy (occurring within first 7 days)
• Most (80%) do so within first 2 years
Seat belts
• reduce fatal injuries and severe injuries in survivors, each by a factor of about 4 times
• most marked reduction in head-on crashes
• head injuries caused by frontal impacts against windshield or dashboard greatly reduced
• belts protect against ejection from the car
Home care vs Institutional care
• In PVS/MCS cases
Pre-existing lesion – hypertension with intracerebral
hemorrhage• unknown but severe hypertension
• a minor injury or some form of physical stress/exertion
• common sites of hypertensive hemorrhage
ICH
Pre-existing lesion – aneurysm with subarachnoid hemorrhage
• Asymptomatic aneurysm
• Minor head injury
• Exertion
Pre-existing lesion – anticoagulant use for artificial
heart valves
• anticoagulant at therapeutic level (not overdosed)
• minor head injury
• diffuse/multifocal hemorrhages