Pathology of Head Injury

Question 1

How many hospital admissions?

Answer 1

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

Question 2

Example of a primary insult?

Answer 2

Focal and/or diffuse brain trauma

Question 3

example of secondary insults?

Answer 3

can develop further complications from the primary insult
		Hypotension – low arterial BP
		Hypoxia – low blood oxygen
		Infection
		Haematoma – bleeding in/around brain

Question 4

How to assess someone with a head injury?

Answer 4

conscious level using Glasgow coma scale?

Question 5

what GCS is mild, moderate and severe?

Answer 5

13-15- mild
9-12- moderate
3-8: severe injury

Question 6

complications of a head injury?

Answer 6

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)

Question 7

Examples of scalp injuries?

Answer 7

similar to those that can affect the skin eg. abrasions, bruises, lacerations, incision (and burns/scalds)

blunt force injury

Question 8

describe linear skull fractures?

Answer 8

commonly temper-parietal from blow or fall onto side or top of the head and may continue onto the skull base, “hinge” fracture

Question 9

describe a depressed skull fracture

Answer 9

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

Question 10

describe a committed (mosaic) fracture

Answer 10

fragmented skull

Question 11

describe a “Ring” fracture

Answer 11

: 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

Question 12

describe a “contre coup” fracture?

Answer 12

: fracturing of the orbital plates (anterior fossa) caused by a fall onto the back of the head

Question 13

what causes an intracranial haemorrhage? what is the pathology?

Answer 13

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

Question 14

what is an extradural haemorrhage?

Answer 14

Bleeding occurring between the dura and the skull; accumulating blood strips the dura off the inner surface of the skull

Question 15

what causes an extradural haemorrhage usually?

Answer 15

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

Question 16

what is Lucid interval? when can it occur

Answer 16

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

Question 17

what is a subdural haemorrhage?

Answer 17

Bleeding occurring beneath the dura (and above the arachnoid)

Question 18

what can cause a subdural haemorrhage

Answer 18

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

Question 19

what can be seen alongside a subdural haemorrhage?

Answer 19

“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)

Question 20

examples of intrinsic brain injuries?

Answer 20

cerebral oedema

cerebral comtrusion and laceration

Question 21

what is a cerebral oedema?

Answer 21

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”

Question 22

what is a cerebral contusion and laceration?

Answer 22

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]

Question 23

what is an axon?

Answer 23

elongated processes of nerve cells which permit transmission of signals between different parts of the brain and between the brain and body

Question 24

are diffuse traumatic axonal injuries caused just by trauma injuries?

Answer 24

not just caused by trauma, therefore the teen “traumatic DAI” is used

Question 25

how can a tDAI diagnosis made?

Answer 25

tDAI is a diagnosis which can only be made by microscopy of the brain tissue (special staining techniques - APP - are frequently required to detect the damage), but may get concomitant damage to small blood vessels within the brain which raise suspicions of tDAI.

Question 26

what are the usual scenarios that can cause a a tDIA?

Answer 26

vehicular collisions and falls from a height; serious rotational forces applied to the brain tissue causing shearing of axons

Question 27

what areas of the brain are especially sensitive to a tDIA?

Answer 27

: corpus callosum, para-sagittal white matter, posterior internal capsule and dorsolateral aspects of the rostral brainstem, as well as the cerebellar peduncles

Question 28

what happens to a patient when a tide is fully developed?

Answer 28

victims are comatose when tDAI is fully developed

Question 29

what would it mean if a patients with a tDAI has a concussion?

Answer 29

Concussion: may well be the clinical manifestation of lesser degrees of axonal injury - may have retrograde amnesia