Head Injury is a phrase referring to a vast array of injuries occurring to the scalp, skull, brain, or the underlying tissue and blood vessels within the head. Based on the extent of the head trauma, a head injury is commonly referred to as brain injury or traumatic brain injury. Head injury nursing care varies according to the cause, damage and complications.
The Parietal and Temporal bones are more likely to fracture in a head injury. And since the brain is quite soft in texture, a cranium injury can easily be the cause of a brain injury.
The Meninges
The meninges consist of three membranous connective tissue which enclose the brain, namely the pia mater, arachnoid mater and dura mater.
PAD – the 3 layers of the brain = Pia Mater, Arachnoid Mater, and Dura Mater.
Cerebral Blood Flow
The brain has high metabolic demands. It depends on ongoing energy/glucose which can be supplied through continuous blood flow, especially since it does not store any glucose itself. Blood is supplied to the brain through 4 arteries which are fused together, forming the Circle of Willis.
- the brain amounts to not more than 2% of the total body weight
- the brain requires between 15 to 20% of resting cardiac output (50ml/100g of brain tissue per minute which amounts to 700ml/min in an individual weighing 70kgs)
- the brain requires 15% of the body’s total oxygen demand
- the brain doesn’t store glucose, and doesn’t have any glycogen stores
- the brain doesn’t tolerate hypoperfusion
Traumatic Brain Injury
A traumatic brain injury refers to a blunt or penetrating head injury which disrupts the brain from functioning in its normal way, causing impaired thinking and memory, personality changes, and sometimes sensory and motor changes.
A traumatic brain injury can be classified as either Primary or Secondary, as listed below…
| Primary Brain Injury | Secondary Brain Injury |
|---|---|
| – damage incurred at the time of injury | – complications following initial injury |
| – cerebral laceration | – hypoxia / ischaemia |
| – concussion / contusion | – brain oedema |
| – skull fractures | – brain herniation |
| – intracranial bleeding | – intracranial hypertension |
| – diffuse axonal injury | – CSF leak and infection |
A primary brain injury can only be prevented through education and health promotion, whilst a secondary brain injury can be prevented from a clinical point of view.
Primary Brain Injury
Focal Injuries:
- affect specific brain locations as in cerebral contusion (scattered areas of bleeding on the brain’s surface, commonly located along the under-surface and poles of the frontal and temporal lobes), laceration, or intracranial haemorrhage (bleeding into the brain tissue – can be classified as Epidural Haematoma, Subdural Haematoma, Subarachnoid Haemorrhage, or Intracerebral Haemorrhage)
Diffuse Injuries (diffused/spread injuries):
- concussion (caused by a bump, blow, or jolt to the head, or by a hit to the body which causes the head and brain to move rapidly back and forth)
- moderate to severe Diffuse Axonal Injury (shearing of the brain’s long connecting nerve fibers a.k.a. axons, which happens when the brain is injured through shifting or rotating inside the skull; DAI commonly causes coma and injury to many different parts of the brain)
Cerebral Contusion ~ Focal Injury
Cerebral Contusion refers to scattered areas of bleeding on the brain’s surface, commonly located along the under-surface and poles of the frontal and temporal lobes. This is typically caused by coup and/or contrecoup injuries, happening by:
- blunt trauma to the brain tissue
- bruising of the brain due to capillary bleeding into superficial brain tissue, typically in the frontal or temporal bone areas of the skull
Cerebral Contusion signs & symptoms may include:
- confusion
- neurological deficit (featuring changes related to personality or speech and vision)
Cranial Fracture ~ Focal Injury
Types of cranial fractures include:
- Linear Fracture – a thin-line break in a cranial bone, without any splintering, depression, or distortion of bone; in a linear fracture, the dura mater remains intact
- Depressed Fracture – a break in the cranial bone or a crushed part on the skull with depression of the cranial bone toward the brain
- Open Fracture – an injury in which the fractured bone or haematoma are exposed to the external environment due to a traumatic violation of the soft tissue and skin; the wound may lie at a site distant to the fracture, not directly over the fracture itself
- Impaled Object – an injury in which an object remains impaled into the cranium eg. a bullet or knife; it is crucial that no one attempts to remove an impaled object unless in a healthcare facility where emergencies can be attended to
Base of skull fracture a.k.a. basilar skull fracture ~ Focal Injury
Typical signs of a base of skull fracture include:
- Raccoon Eyes – unilateral and/or bilateral periorbital ecchymosis
- Battle’s Sign – unilateral retro-auricular / mastoid ecchymosis
- Haematotympanum – blood behind the ear drum
- Halo’s Sign – a fracture located at the base of the skull may lead to blood or CSF leakage, or both, from the nose (rhinorrhoea) and/or the ear (otorhoea); CSF is a straw-coloured fluid which typically produces the ‘halo sign’
Retrieved from https://www.semanticscholar.org/paper/Periorbital-Ecchymosis-%28Raccoon-Eye%29-and-Orbital-Nasiri-Zamani/0337e88c6d4e2ff8d234edc189bee96dc2bdaca3, https://25hournews.com/news/the-battle-sign-that-appears-behind-the-ears-3000 & https://onlinelibrary.wiley.com/doi/pdf/10.1197/j.aem.2003.09.004 on 26th December 2022
Basilar Skull Fracture Head Injury Nursing Care
- DO NOT perform nasal suctioning
- DO NOT attempt to insert a NGT
- If a gastric tube is indicated, it is better to insert an orogastric tube instead. The risk is higher with NGT insertion than with an orogastric tube because the roof of the nasal cavity is practically shared with the base of the skull
- DO NOT plug bleeding site – instead wipe drainage with a sterile swab
- Instruct patient to perform NO STRAINING and NO VALSALVA (breathing method that may slow the heart during tachycardia)
- QUERY SURGERY – if indicated, surgery may be attempted to seal CSF leak, repair damaged vessel/s or relieve ICP
Complications:
- brain injury
- cranial nerve palsy
- blood vessel injury
- CSF leak (may lead to infection: meningitis)
Intracranial Bleed ~ Focal Injury
Risk factors for intracranial bleeds include:
- basilar skull fracture
- older age
- previous neurosurgery
- use of anticoagulants
- blood clotting disorders
- history of loss of consciousness
- retrograde amnesia (amnesia where one cannot recall memories formed before the event which caused the amnesia)
- anterograde amnesia (memory loss which occurs when one cannot form new memories, permanently losing the ability to learn or retain new information)
Epidural Haematoma ~ Focal Injury
FACTS:
- bleeding is located between the skull and the dura mater
- commonly results from a temporal bone fracture
- commonly involves arterial bleeding, usually from the middle meningeal artery
- typically features a ‘lucid interval’, which is a temporary improvement in the patient’s condition after a traumatic brain injury, following which fast deterioration occurs
- if left undrained may displace brain into foramen magnum
- requires immediate surgery
CT SCAN FEATURES:
- edges are sharply defined
- convex or lens-shaped appearance
- the dura strips from the cranium’s under-surface, causing the haematoma to assume its shape
- the ventricular system’s midline shifts to the side opposite the haematoma
Subdural Haematoma ~ Focal Injury
FACTS:
- venous bleed occurs between the dura mater and the arachnoid mater, within the meninges
- bleed may be acute, sub-acute, or chronic
- neurological deterioration progresses slowly
- risk factors include trauma, hypertension, anticoagulant use, and alcohol abuse
- excessive blood is usually drained by an extravascular catheter
CT SCAN FEATURES:
- an acute subdural haematoma presents in a crescent shape, covering the entire brain surface
- prognosis for an acute subdural haematoma is worse than that of an epidural haematoma, with underlying brain damage typically being more severe
- rapid surgical evacuation is required especially in the case of >5mm midline shift and raised intracranial pressure
Subarachnoid Haemorrhage ~ Focal Injury
FACTS:
- blood pooling is located in the subarachnoid space, between the arachnoid membrane and the pia mater
- bleeding happens spontaneously through ruptured aneurism, trauma, or hypertension
- a common sign of a subarachnoid haemorrhage is a ‘thunderclap headache’ – a headache that strikes suddenly like a clap of thunder as the name implies
CT SCAN FEATURES:
- in a CT scan, a subarachnoid haemorrhage appears as a high-attenuating, amorphous substance that fills the normally dark, CSF-filled subarachnoid spaces around the brain
ATTENTION!!
- avoid an increase in intracranial pressure
- explore possibility of surgery for haematoma drainage
- explore possibility of surgery for aneurism clipping
Intracerebral Haemorrhage A.k.a. intraparenchymal cerebral haemorrhage ~ Focal Injury
FACTS:
- blood pooling caused by rupture of a blood vessel within the brain tissue – the cerebrum
- may be a spontaneous rupture as in a CVA
- may be caused by a traumatic event as in a penetrating injury, depressed skull fracture, contusion, or laceration
- signs and symptoms are similar to that of a stroke
- prognosis depends on the size and location of the intracerebral haemorrhage, however, this type of haemorrhage carries a high mortality rate
CT SCAN FEATURES:
- a CT scan of an Intracerebral Haemorrhage features a hyper-dense collection of blood, commonly surrounded by hypo-dense oedema
- complications such as extension of the haemorrhage into other intracranial compartments may also be present
Concussion ~ Diffuse Injury
FACTS:
- the brain remains structurally intact when a concussion is incurred
- transient loss of consciousness may take from a couple of seconds to hours
- concussion prognosis is commonly a complete recovery without treatment
SIGNS & SYMPTOMS:
- mild headache
- dizziness
- lethargy
- irritability
- poor concentration
- confusion / disorientation
- post-traumatic amnesia
Severe Diffuse Axonal Injury
FACTS:
- shearing and tearing of axons in the cerebral hemispheres and brainstem usually result from rapid deceleration
- damage is on a microscopic scale, thus is usually invisible in tests
- symptoms include coma, persistent vegetative state, and abnormal posture
- severe diffuse axonal injury carries a high mortality rate
Secondary Brain Injury
As previously mentioned, a primary brain injury can only be prevented through education and health promotion, whilst a secondary brain injury can be prevented from a clinical point of view.
For this reason, another blogpost focusing on secondary brain injury prevention will be published in the upcoming days. Subscribe below to receive notification of newly published blogposts in your inbox 😉
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