Pathology of Head Injury Flashcards
How many hospital admissions?
250/100k
10 people out of the 100k have serious permanent neurological deficit
10 people per 100K die,
-most common in uk are road traffic and alcohol-related accidents including assaults
Example of a primary insult?
Focal and/or diffuse brain trauma
example of secondary insults?
can develop further complications from the primary insult Hypotension – low arterial BP Hypoxia – low blood oxygen Infection Haematoma – bleeding in/around brain
How to assess someone with a head injury?
conscious level using Glasgow coma scale?
what GCS is mild, moderate and severe?
13-15- mild
9-12- moderate
3-8: severe injury
complications of a head injury?
Permanent physical disability-paralysis speech impairment- depends what part of brain injured
Post traumatic epilepsy
Intracranial infection-brain absesses meningitis
Psychiatric illness
Chronic subdural haemorrhage
‘Punch-drunk’ dementia
Fatal outcome (uncommon)
Examples of scalp injuries?
similar to those that can affect the skin eg. abrasions, bruises, lacerations, incision (and burns/scalds)
blunt force injury
describe linear skull fractures?
commonly temper-parietal from blow or fall onto side or top of the head and may continue onto the skull base, “hinge” fracture
describe 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
describe a committed (mosaic) fracture
fragmented skull
describe a “Ring” fracture
: fracture line encircling the foramen magnum caused by a fall from height, usually landing on the feet, but sometimes the head, leading to the skull base and cervical spine being forced together
describe a “contre coup” fracture?
: fracturing of the orbital plates (anterior fossa) caused by a fall onto the back of the head
what causes an intracranial haemorrhage? what is the pathology?
Accumulation of blood within the rigid skull causes an increase in intracranial pressure (ICP) and results in compression of the brain this compression causes symptoms, including reduction in conscious level.
As ICP increases, without intervention, ultimately death will occur by compression of the brainstem due to herniation of the cerebellar tonsils into the Foramen Magnum
what is an extradural haemorrhage?
Bleeding occurring between the dura and the skull; accumulating blood strips the dura off the inner surface of the skull
what causes an extradural haemorrhage usually?
Vast majority arise from damage to an artery in association with a skull fracture (80-90%) and, therefore, under higher pressure than with venous bleeding, but very occasionally large venous channels can cause EDH
- caused by bleeding from the middle meningeal artery where it crosses the inner aspect of the squamous temporal bone due to fracture of the squamous temporal bone with secondary damage to the artery in the vicinity of the fracture
- accumulation of blood (haematoma) can cause raised intracranial pressure with developing neurological symptoms; the time period for the development of symptoms is variable, can be rapid, but can take many hours
what is Lucid interval? when can it occur
can occur in extradural haemorrhage
“Lucid interval” can occur - victim of injury initially seems to be okay, without neurological symptoms, but can deteriorate catastrophically later, which can be a source of difficulty for clinical staff who may be accused of being negligent if they fail to recognise the possibility of intracranial bleeding
what is a subdural haemorrhage?
Bleeding occurring beneath the dura (and above the arachnoid)
what can cause a subdural haemorrhage
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
Any motion which causes rotational or “shearing” forces can cause the veins to be stretch and torn due to the relative movement between the brain and the dura
Frequently occurs without a skull fracture
Individuals with atrophic (small) brains are at increased risk because the smaller brain has greater capacity for movement and the veins may be already stretched to some degree
-Individuals with atrophic (small) brains are at increased risk because the smaller brain has greater capacity for movement and the veins may be already stretched to some degree
what can be seen alongside a subdural haemorrhage?
“Lucid interval” may be seen with SDH
Can get chronic subdural haemorrhage, particularly in elderly, and may be a cause of chronic confusion (and may be mistaken for dementia)
examples of intrinsic brain injuries?
cerebral oedema
cerebral comtrusion and laceration
what is a cerebral oedema?
common and rapid result of brain injury, especially in children (“malignant cerebral oedema”)
Can develop in minutes and lead to massive brain swelling with raised intracranial pressure and “coning”
what is a cerebral contusion and laceration?
direct mechanical damage to the brain substance
May occur anywhere on the brain
“Coup” contusion: occurs when a head is struck a heavy blow - the contusion is found directly under the site of impact
“Contre-coup” contusions: caused by a moving head striking a fixed object or unyielding surface - contusions are found diametrically opposite the site of head impact, e.g. a fall onto the back of the head would result in contusions on the frontal and temporal poles and on the undersurface of the frontal lobes [NB: contre-coup fractures]
what is an axon?
elongated processes of nerve cells which permit transmission of signals between different parts of the brain and between the brain and body
are diffuse traumatic axonal injuries caused just by trauma injuries?
not just caused by trauma, therefore the teen “traumatic DAI” is used
