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) 4Spontaneous 3To questions/command 2To pain 1Nil Verbal response (V) 5Normal and oriented 4Confused speech 3Inappropriate speech 2Incomprehensible words 1Nil Motor response (M) 6Normal and following commands 5Localize pain 4Withdrawal to pain 3Flexor posturing 2Extensor posturing 1No response

Severity of head injury MildGCS 14 to 15 ModerateGCS 10 to 13 SevereGCS ≤ 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 hematoma Intracranial bleeding -intracerebral -intraventricular -subarachnoid -extradural -subdural -combination

ICH

EDH

SDH

SAH

PARENCHYMAL DAMAGE Contusion Diffuse 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

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