Head Injuries Flashcards
Types of head injury
Penetrating
- gunshot
Non-penetrating
- blunt force trauma - RTC, fall from height
Key features of head injury
Major cause of death and disability in developed countries
- RTA
- Assault
- Accidents
Head is heavy, freely mobile and unstable
Vulnerable to impact, rotation and acceleration/declaration
Movement of brain within skull
Assessment of head injury
Prognosis related to length and depth of unconsciousness Glasgow Coma Scale /15 - motor response /6 - verbal response /5 - ocular response /4
Anatomy of head injury
Scalp Skull - rigid structure - one exit foramen magna Dura - cranial cavity divided by reflections of dural membrane - into Rand L by falx and upper and lower by tentorium cerebelli Brain - semi solid consistency - vulnerable to impact, rotation, acceleration, deceleration and swelling
Features of primary head injury
Scalp - abrasion - bruising + swelling -> haematoma - laceration - rich blood supply -> heavy bleeding Skull fracture Intracranial haemorrhage Brain injury
Factors affecting force required to cause skull fracture
Thickness of hair Thickness of scalp Thickness of skull - hyperostosis Site of impact Direction of impact
Types of skull fracture
Linear Comminuted - greater than 2 fragments Radiating Spider's web Depressed Hinge - goes across base of skull creating hinge Ring Contre-coup - occur opposite point of impact
Types of intracranial haemorrhage
If forms distinct mass called haematoma Extradural Subdural Subarachnoid Intracerebral
Features of extradural haematoma
Due to blow to temple
May cause LOC
Fracture tears an artery within groove in inner table of skull
- usually middle meningeal artery inside thing temporal bone
- rarely may arise from venous sinus
Arterial bleeding forcibly strips dura off skull
Localised to enlarging haematoma by dura
Lucid interval
Later pressure effects (LOC) from enlarging haematoma
If untreated 75-100mls maybe fatal
Amenable to surgical decompression
Features of subdural haemorrhage
Due to fall or blow - often trivial
Common in alcoholics, elderly and children
Not usually associated with skull fracture
Shearing of bridging veins spanning subdural space - between dural sinuses and cortical veins
Blood spreads widely over brain surface
50-100mls life threatening
Often asymptomatic
Causes of subarachnoid haemorrhage
Natural - ruptured berry aneurysm Traumatic - arising from contusion or laceration to brain surface - blow to chin - traumatic basal SAH
Features of traumatic basal SAH
Blow to chin or angle of jaw jerks head
-> stretching and rupture of vertebral artery
Immediate collapse and death - minutes
Strong association with alcohol intoxication
Death comes as surprise to all
Culpable homicide
- as usually not intentional
Causes of intracerebral haemorrhage
Natural
- rupture of small artery
- most common in hypertension
Traumatic
- arising from contusion or laceration to brain surface
- shearing and tearing of deep blood vessels
Features of brain injuries
Cerebral contusion - bruising to brain surface
- coup - at point of impact
- contre-coup - diagonally opposite point of impact
Cerebral laceration
- from impact or fracture
Diffuse traumatic axonal injury
Cerebral swelling and hypoxia
Features of concussion
Transient LOC
Retrograde amnesia
Temporary nerve cell dysfunction due to impact
No residual structural damage
