Head injury Flashcards
What are the clinical aspects of head injury?
Non missile vs missile
Focal vs diffuse
Primary vs secondary
What are the types of head injury?
Scalp injuries
Skull fractures
Intracranial haemorrhage- EDH, SDH, SAH
Intrinsic brain injury- oedema, contusions, lacerations, herniation
Diffuse traumatic axonal injury
What are the types of scalp injuries?
Abrasions
Bruises
Lacerations
Incisions
Burns
What are the types of skull fractures?
Linear
Depressed
Comminuted
Ring
Contre-coup
Diastatic
What is linear skull fracture?
Commonly temporo-parietal from blow or fall onto side or top of head
What is depressed skull fracture?
Focal impact which may push fragments inwards to damage the meninges, blood vessels and brain
Force over small area
What is comminuted skull fracture?
Fragmented skull
AKA mosaic fracture
Force over large area
What is ring skull fracture?
Fracture line encircling foramen magnum
Skull base and cervical spine forced together
What is contre-coup fracture?
A fracture of the cranial vault occurring at a site approximately opposite the point of impact
What is diastatic fracture?
Follows suture lines
Children
What is EDH?
Extradural haemorrhage
Accumulation of high-pressure arterial blood strips dura off inner surface of skull
Egg shaped haematoma that accumulates over a few hours
What causes the majority of EDHs?
Fracture of squamous temporal bone
Causes tear in middle meningeal artery
What is SDH?
Subdural haemorrhage
Accumulation of low- pressure venous blood from bridging veins
Crescent shaped haematoma
When does acute SDH become chronic?
> 2 weeks
Soft jelly consistency of haematoma is broken down into serous fluid
Membrane of granulation tissue forms
What causes SDHs?
Any motion which causes rotational/shearing forces can cause the veins to stretch and tear
What is SAH?
Subarachnoid haemorrhage
Rapid collapse and quick death
Associated with cerebral contusions
Sudden onset of worst ever headache
What is the most common cause of SAH?
Rupture of cerebral artery -> berry aneurysm
What is xanthochromia?
The yellowish appearance of cerebrospinal fluid that occurs several hours after bleeding into the subarachnoid space
What is the management of SAH?
Coiling
Surgical clipping
Nimodipine to reduce vasospasm (calcium channel blocker)
Insertion of extra ventricular drains of hydrocephalus occurs
Why is surgical clipping not first line intervention?
Involves craniotomy is is a more invasive procedure than coiling
What are the 2 types of brain contusions?
Coup contusions
Contre-coup contusions
What are the types of brain herniation?
Subfalcine herniations
Central herniation
Transtentorial uncal herniation
Cerebellar tonsillar herniation
What is transtentorial uncal herniation?
Also known as coning
Transforaminal herniation of brainstem and cerebellar tonsils through foramen magnum
What is diffuse traumatic axonal injury?
Tearing of axons in white matter
Due to high force rotation acceleration-deceleration injury
What areas of the brain are susceptible to diffuse traumatic axonal injury?
- Corpus callosum
- Para-sagittal white matter
- Posterior internal capsule
- Dorsolateral aspects of rostral brainstem
- Cerebellar peduncles
What biochemical changes in the brain can cause injury?
Head injury triggers cascade of biochemical changes:
- Glutamate causes massive calcium influx which has a neurotoxic effect
- Nitrous oxide has a neurotoxic effect
What pathology is associated with head injury alongside long bone fractures?
Fat embolism
Lodges in lungs and cranial blood vessels
Multiple petechial haemorrhages in white matter
What is the management of head injury?
Stabilise cervical spine
ABC
Intubation and ventilation if GCS<8 (Glasgow coma scale)
Treat raised ICP
Cranial imaging
Neuro observation
What is involved in treatment of raised ICP?
- Surgery to relieve pressure
- Osmotic diuretics e.g. mannitol
- Reduce pain
- Maintain good PO2, reduce PCO2
- Reduce metabolism- reduce temperature, barbiturates
- Sit up patient
- Avoid neck compression
