Head Injury Flashcards
(34 cards)
What can head injuries be a result from?
Accidental: (very common)
- Falls (esp from a height)
- RTA
Homicidal: (also frequent)
- Conseqence of being struck
(e. g. hammer, axe, brick)
Suicide:
-Fall from height
Natural disease:
-May cause collapse with resulting head injury which can prove misleading on initial investigation
What are scalp injuries similar to?
Similar to injuries effecting the skin.
- Abrasions,
- Bruises,
- Lacerations,
- Incisions
- (and burns and scalds
Why is the scalp a common site for laceration?
Scalp is closely applied to the skull and tearing associated with the application of force more likely to occur in these circumstances.
The laceration may be suprisingly clean cut, potentially mimicking an incised wound
Why can the scalp be decieving in head trauma?
Blunt force injury to the head may not be visible on the surface of the scalp.
hair can obscure sizable injuries to the scalp
-Shaving advisable at autopsy
May only have bruising/bleeding in the deeper layers of the scalp or between the scalp and the skull.
This is of particular note in infant head injury (impact versus shaking)
How do adults and infants differ when it comes to skull fracture?
Skull fractures caused by application of force causing deformation of the skull
Adult skulls less likely to cope with distortion.
Infants may resolve distortion as the head grows
What are the two elemets to the skull?
Skull vault (upper part) which includes frontal bone, squamous temporal bones and occipital bone separated by sutures
Skull base (upon which the brain rests) which can be divided into the anterior, middle and posterior cranial fossae
What are the types of skull fracture?
Linear Depressed Comminuted "Ring" Fracture "Contre-coup" fracture
What is a linear skull fracture?
Commonly temper-parietal from blow or fall onto side or top of the head and may continue onto the skull base, “hinge” fracture
What is a depressed skull fracture?
Focal impact which may push fragments inwards to damage the meninges, blood vessels and the brain; risk of meningitis and post-traumatic epilepsy.
Not typical of a fall from standing onto a flat surface, e.g. pavement fractures tend to be linear in this scenario
What is a comminuted skull fracture?
Mosaic skull fracture
Fragmented skull
What is a “Ring” fracture?
Fracture line encircling the foramen magnum caused by fall from eight, usually landing on the feet, but sometimes the head, leading to the skull base and cervical spine being forced together
What is a “contre-coup” skull fracture?
Fracturing of the occipital planes (anterior fossa) caused by a fall onto the back of the head
How are intracranial haemorrhages named?
By their position within the skull in relation to the meninges
(i.e. extradural, subdural and subarachnoid haemorrhage)
Why is diagnosis of intracranial haemorrhage hard?
What helps with this?
The different forms of intracranial haemorrhage may all be caused by trauma, typically blunt force trauma, but by different mechanisms, in varying circumstances and may present to clinical staff in a variety of ways.
Diagnosis is greatly assisted by advances in radiological images, particularly CT scan
What does intracranial haemorrhage cause?
Accumulation of blood within the rigid skull causes an increase in ICP and results in compression of the brain.
The compression causes symptoms including reduction in conscious level and if unchecked, will ultimately cause death by compression of the brainstem due to herniation of the cerebellar tonsils into the foramen magnum
What is extradural haemorrhage?
Bleeding occuring between the dura and the skull; accumulating blood strips the dura off the inner surface of the skull
How do the vast majority of extradural haemorrhages arise?
Damage to an artery in association with a skull fracture (80-90%)
(Usually middle meningeal)
Arterial so under higher pressure than with venous bleeding (very occasionally large venous channels cause EDH
What is the “lucid interval” in extradural haemorrhage?
Victum of injury inicially seems to be ok, without neurological symptoms, but can deteriorate catastrophically later, which can be a source of difficulty for clinical staff who may easily miss possibility of intracranial bleeding
What is subdural haemorrhage?
Bleeding occuring beneath the dura (and above the arachnoid)
Usually caused by bleeding from bridging veins which pass from the surface of the brain to drain into the large venous channels within the dura
What can cause subdural haemorrhage?
Any motion which causes rotational or “shearing” forces can cause the bridging veins to stretch and tear due to the relative movemnt between brain and dura.
Frequently occurs without a skull fracture
What individuals are more at risk of a subdural haemorrhage?
Individuals with atrophic (small) brains are at increased risk because the smaller brain has a greater capacity for movement and the veins may already be stretched to some degree
Is a lucid interval seen in subdural haemorrhage?
May be seen
What is a chronic subdural haemorrhage?
Chronic presence of blood between arachnoid and dura mater.
Particularly in elderly as brain will be smaller so compensates well with extra fluid.
May be a cause for chronic confusion (and may be mistaken for dementia)
What is a subarachnoid haemorrhage?
Bleeding beneath the arachnoid membrane (and above the brain)
Bleeding causes irritation to the brain -> worst headache someone has ever had
