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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?.
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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 hematoma Intracranial bleeding - intracerebral - intraventricular - subarachnoid - extradural - subdural - combination
SDH SAH
PARENCHYMALDAMAGE 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
Vascular damage • Dissection of internal carotid artery • 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