HEAD INJURY
Last updated 12/11/23
Introduction
Colloquially and in MR, the term ‘head injury’ is a generic term and is used for any insult to the head, from minor to severe. Although this includes the skull and skin covering, the brain is obviously the thing we are most concerned about. When the brain itself is injured, the term ‘traumatic brain injury’ (TBI) is used. This is the main focus of this section.
In the case of e.g. a fractured ankle, by the time we get there, the fracture (primary injury) has happened, but we look for skin tenting, poor circulation to the limb and changes in sensation, and treat these to prevent secondary injuries from occurring. The same applies to TBI. The primary injury results from the initial trauma at the time of the incident, and the secondary injury, is further damage that occurs via a variety of mechanisms after the primary injury. Once the brain has been injured, there is nothing that can be done to undo the damage. However, secondary brain injury, is very amenable to intervention. When dealing with head injuries, the aim for all prehospital emergency services is to prevent, or at least minimise, secondary brain injury. Because it is so important, this is discussed in detail below.
It can be difficult to definitively rule out TBI on the hill. Therefore, any blow to the head, with or without loss of consciousness, should raise concern. Perform a full assessment, as described below, and take any necessary steps if it is likely that the brain has been injured. It is far better to err on the safe side, as the brain is not a very forgiving organ.
All casualties with evidence of brain injury need urgent evacuation, ideally by air
Intracranial pressure (ICP)
The brain is enclosed in a box (the skull) and floats in Cerebrospinal Fluid (CSF). The pressure inside the skull is called the intracranial pressure or ICP (from the word ‘cranium’ which is the medical word for skull). The ICP is normally quite low and can’t be measured outside hospital.
Because the skull cannot alter in size, there is very little room inside for extra material. Therefore, anything that reduces the space for the brain will cause major trouble. This can happen in two ways:
Bone (skull) can be depressed inwards following an impact, which not only reduces the internal volume of the skull but also presses directly on the brain.
The size of the contents can increase because not only will the brain swell after injury, but there might be additional blood (either as free blood or blood clot from the injured brain).
The relation between brain volume and pressure within the skull is not linear. Initially, the volume of CSF decreases to make room for the additional contents. After that compensatory mechanism is exhausted, the pressure inside the skull rises quickly. This is depicted in the graph on the right. An increase in ICP is extremely serious because vital centres in the brain cease functioning. Untreated, this will result in brain death. Clinically, the features of increased ICP are
Decreasing fall in conscious level (fall in GCS)
Eye abnormalities (unequal pupils; squint)
Very high BP + low pulse rate (the opposite of shock) and irregular breathing are late signs
Seizures
Following trauma, a bleed inside the skull will compress the brain
Assessment of a brain-injured casualty
History
We need as much information as possible pertaining to three periods of time. It may be possible to get this from the casualty, but in more severe cases, it will be from a bystander.
What happened immediately before the accident
Any alcohol or drugs consumed?
Was the casualty behaving normally?
If a fall was involved, were they fully conscious beforehand or had something changed e.g. seizure, feeling faint, etc.?
Details of the actual accident
Details of the injury e.g. tumbling fall
Was there an impact to the head, either from a fall or because something hit the head, e.g. falling boulder?
Loss of consciousness at the time of the accident? If so, how deep and for how long?
Any other injuries?
What has happened since
The most important thing is conscious level immediately after the event and subsequently:
If they were knocked out, how long until they started to recover consciousness?
Struggling to stay awake?
Any fluctuations in conscious level over time? Is it improving or worsening?
Confusion (especially if new). If so, any periods of lucidity i.e. when they seemed to be normal again?
Other neurological effects
Changes in vision?
Any problems understanding, speaking or writing?
Any unusual behaviour?
Some people become combative after a head injury.
Amnesia. Can they remember the events immediately before the injury and afterwards?
Have they been able to walk since the time of the fall? Any trouble with their balance?
Miscellaneous things
Nausea / vomiting
Headache
Dizziness
High risk casualties
Children <4y.
People >60y old. A small head injury can be significant in older people.
Casualty taking drugs that interfere with blood clotting e.g. warfarin, as this can increase the amount of bleeding
Signs
Rapid deceleration of the head can cause a brain injury without any external evidence of head trauma. This is explained in the upper diagram on the right. Because the brain is floating in CSF, it bounces back and a further injury occurs to the other side of the brain, in this case, the back (‘contrecoup’).
Assess
Peripheral issues
If a helmet was worn at the time of the incident, check it for signs of damage and ensure it goes with the casualty to hospital
The head
Scalp or facial injuries
Blood on the head, face or ground
Boggy swellings on the head (indicate a likely underlying skull fracture)
Later signs of base of skull fracture:
Black (raccoon) eyes (can start to become visible in an hour, but often takes hours, and days to become as florid as this photo)
Bruising behind the ear (Battle's sign; can take a day to develop)
Bleeding or cerebrospinal fluid (CSF) leaking from the ear and/or nose. This is discussed in more detail below.
Conscious level. This is the single most important thing because it assesses overall brain function. Assess using AVPU.
Basic neurological assessment
Pupil shape, size and reaction to light (see Disability for details)
Seizures
Impaired movement or sensation in the limbs that is not due to physical injury
Respiratory abnormalities. For example, sometimes after a significant brain injury, the casualty will almost hyperventilate.
Some people become combative after brain injury.
If there is time, you can attempt to do Glasgow Coma Score (GCS) - see below
Raccoon eyes
A real raccoon
Battle’s sign
Due to the strong association between head and spinal cord injuries, movement and sensation in the limbs should be checked and recorded. Assess MSC in all four limbs.
Motor - test for movement
Sensation - apply light touch
Circulation - assess cap refill and skin temperature
Management
Remember - there may be more than one thing going on. After assessing and treating the head injury, always check for other causes of impaired conscious level since they may have precipitated the head injury e.g. a stroke causing a fall, epileptic fitting or hypoglycaemia etc.
The consumption of drugs including alcohol can complicate the assessment of head injuries. Never presume reduced levels of consciousness are solely due to the effects of intoxication. If TBI is suspected in the presence of drugs or alcohol, always treat as though the TBI is the only cause.
If brain matter can be seen through an expose scalp injury, cover with a light dressing.
Cervical spine
Important - Head injuries are often associated with an increased risk of cervical spine injury. The possibility of spine injury should be considered in all head injuries. If in doubt, take a precautionary approach and immobilise the spine. Initial airway management should be via the jaw thrust and not by head tilt - chin lift. After a head injury, it might not be possible to clear the C-spine using NEXUS if consciousness is impaired.
Cervical collars in TBI
Collars have many disadvantages, such as making airway management more difficult. Therefore, nowadays, the emphasis is increasingly on avoiding using them. If a decision is taken to use one, be very careful to ensure the collar does not constrict the jugular veins as this can increase back pressure on the brain.
Prevention of secondary brain injury
As described above, this is damage occurring after the initial injury. It is due to:
Hypoxia
Inadequate breathing rate/depth
Hypotension (low blood pressure)
Hypoglycaemia
Hyperthermia
Seizures
Breathing problems
Impaired gas exchange is common with TBI and occurs for several reasons:
The injury itself can affect the brain’s ability to control breathing
The fall in conscious level prevents the victim from keeping their airway clear
Accompanying injuries might impair the quality of breathing, particularly facial and chest trauma
The result of any or all of the above is not only hypoxia (lack of oxygen), but also a build up of carbon dioxide in the blood.
Management
ENSURE THE AIRWAY IS CLEAR
A partially obstructed airway is very common after TBI and is the single biggest cause of further damage.
Keep the airway clear of excessive secretions or blood using careful suction if necessary
Use an OPA or NPA if necessary.
Assist breathing in cases of respiratory depression via bag valve mask or i-gel and bag, if severely unconscious and the i-gel is tolerated.
Coughing causes a rise in ICP because the high pressure in the chest when we cough is transmitted to the brain via the veins.
Supplementary oxygen in TBI: as discussed in the section on Breathing, we are nowadays more cautious about giving oxygen to people who have had a myocardial infarction or stroke, because there is emerging evidence that too much oxygen can cause further damage. The same may be true with TBI. Therefore:
if the casualty has an isolated head injury and has sustained no other trauma, we should attempt to monitor the SpO2 and only give additional oxygen if it is <94%.
However, if there is disturbed conscious level that could be causing respiratory depression, or there is other trauma, particularly chest or facial, which can significantly affect the quality of breathing, give additional oxygen via a non-rebreathing mask in the usual way. Manage any treatable trauma that could be affecting breathing in the normal way.
Some people become combative after a head injury. Whilst this is usually directly due to brain damage, it will be exacerbated by hypoxia e.g. if there are chest injuries.
If in doubt: always give oxygen. Whilst here may be a risk of giving too much; there is definitely a risk of not giving enough.
Circulation
Once airway problems have been overcome the next priorities are:
to prevent falls in blood pressure by controlling haemorrhage
compensating for fallen blood pressure
If blood pressure falls below 100 mm Hg and an appropriately qualified person is present they can cannulate and give saline. The aim of giving saline following TBI is to correct hypotension and thereby restore blood pressure to around 100.
Note: If a casualty with a head injury presents with signs of haemorrhagic shock (low BP; high pulse), look elsewhere for other bleeding injuries, a head injury by itself does not cause this picture.
Post head injury seizures
This is not a common problem after head injury but can occur. Treat post-head-injury seizures as for any seizure i.e. buccal midazolam.
Check for and treat hypoglycaemia
To function normally, the normal brain is very dependent on glucose. The injured brain is much more sensitive to even small falls in blood glucose. We normally consider a BM of <4 to need treatment. However, in the presence of TBI, treat a BM of <5 with glucogel.
Check for and treat temperature deviations from normal
Hyperthermia
Although this is unlikely to occur in the scenario of TBI on a mountain, a rise in increased metabolic rate occurs in all tissues including the brain. When it is injured, the brain struggles to obtain sufficient oxygen and nutrients to support basic metabolic requirements. An increase in these could be catastrophic. In the unlikely event on a hill that the casualty’s temperature is elevated, apply cooling by whatever methods are available.
Hypothermia
Although hypothermia protects the normal brain from damage e.g. in hypothermic cardiac arrest, the same is not true for the injured brain, and deliberate cooling of brain-injured patients has not been shown to be beneficial. Therefore, if the temperature is <36°C, apply insulation, external heat, etc. The other situation that hypothermia could be a major problem is if there is also a spinal injury, because the presence of neurogenic shock prevents the body from carrying out normal thermoregulatory responses. This is discussed in the section on spinal injury.
Analgesia for a head-injured casualty
If there is only a superficial injury e.g. a scalp wound, there are no signs of brain injury, and the casualty is stable from that point of view, then all drugs can be used in normal dosages.
Casualties with TBI and other painful injuries needing analgesia
Entonox can be used in casualties with TBI if they are alert enough to self-administer it (GCS 15). In the unlikely event that the casualty starts to become more drowsy whilst breathing Entonox, this will not be due to it but to a coincidental deterioration for other reasons e.g. brain injury deteriorating or severe internal bleeding. Entonox wears off completely within minutes, so if they don’t quickly become as alert as they were before starting the Entonox, something else has happened and needs urgent assessment and management treatment you can deliver. Take the mouthpiece from them, and while someone is maintaining the airway and giving extra oxygen, quickly finish attending to the fracture.
In the presence of TBI, see if paracetamol alone +/- ibuprofen are sufficient to ease the pain.
If simple analgesics are insufficient and the casualty is alert, it will be necessary to use an opioid. If using morphine, just give 5 mg initially. If these doses are insufficient, a second dose can be given, but wait a good 30 minutes before doing so. Fentanyl lozenge is also acceptable if the casualty can co-operate enough to use the lozenge correctly. If in doubt, try to get medical advice. Monitor the casualty regularly, particularly for a change in conscious level.
Watch For Trends
Casualties with head injuries should be monitored closely and reassessed at regular intervals to watch for trends. Regular monitoring and accurate records can be invaluable for alerting us to a deterioration on the hill as well as to the receiving hospital. For example, this sort of information is very useful:
The head injury occurred at 14:00
The casualty was initially alert when we arrived
They gradually became less responsive
By 15:00, the casualty was U on ACVPU and one of the pupils started to get bigger
Key trends to watch for are:
Declining conscious level (ACVPU or GCS)
A significant change in blood pressure (either up or down)
Changes in the size, shape and reactivity of the pupils and inequality between the two that wasn’t present initially
Decrease in respiratory rate (inadequate breathing)
GCS
If conscious level on ACVPU was found to be reduced during the primary survey i.e. anything other than alert and orientated (C, V, P, U), try to assess the casualty using the Glasgow Coma Scale (GCS). There is a guide on the back of the cas card to aid your assessment (shown below).
GCS is a two step process:
1). Assess and note the best response to each of the three individual categories
Remember - that you may not be able to assess Motor in the presence of spinal injury.
2). Combine the scores from each section to get the total score. The lower the score the more severe the brain injury. The highest score is 15; the lowest possible score is 3.
Whilst most of the terms used to make up the Glasgow Coma Scale can be recognised based upon the common meaning of the term, flexion and extension to pain are not encountered in normal life. This is because they are very abnormal responses that only occur in the presence of severe brain injury. To recognise them, you should look for the distinctive type of postures shown below.
Reassess GCS regularly and watch for trends. A fall of 2 points or more during the rescue indicates an extremely serious problem.
If you are interested in learning more about GCS, take a look at https://www.glasgowcomascale.org/. The GCS chart below is from this website and is downloadable from there or here. The video below is introduced by Sir Graham Teasedale, one of the two neurosurgeons who invented the GCS in 1974 in Glasgow. It has stood the test of time and has been found to be extremely useful for assessing brain-injured people.
Concussion
Concussion is a traumatic brain injury resulting in a transient disturbance of brain function. It may be caused either by a direct blow to the head, face, neck, or as a result of an impact elsewhere on the body with a force transmitted to the head. Concussion typically results in the rapid onset of short-lived impairment of neurological function that resolves spontaneously. Because it resolves quickly, there is a temptation to think that it is trivial. However, in some cases, further symptoms and signs may evolve over several hours. Therefore, it must be taken seriously. This is reflected by the fact that there are now international guidelines on the management of concussion, particularly in sport. An example is shown below.
Concussion can happen at any age. However, children and adolescents (18 and under) are more susceptible to concussion, take longer to recover, have more significant memory and mental processing issues and are more susceptible to rare and dangerous neurological complications, including death caused by a single or second impact.
Summary of symptoms: headache, dizziness, nausea or vomiting, mental clouding, confusion, memory disturbance, and balance or visual problems. Importantly, loss of consciousness (being knocked out) occurs in less than 10% of concussions, so is not required to diagnose concussion.
A history of previous concussion increases risk of further concussions, which may take longer to recover.
MR Management
This is the same as for any head injury, as outlined above. The difference is that the person will appear to have recovered. Although someone with a very mild concussion might be fine, this is too difficult for us to assess accurately on the hill. The guidelines above are clear that the casualty should not continue to exercise, but to rest. This means that we should ideally carry them off the hill and they should ideally go to hospital for a more thorough checkup.
Base of skull fracture
The skull comprises of many individual bones that fuse together to form a box. The top of the skull is underneath where your hat sits. The base of the skull is roughly at the level of the ear canals. It is easy to appreciate that a fracture at this level will lie roughly along the black line shown in the diagram and will cut through many important areas. From left-to-right, these are:
Top of the nose (the bridge)
Orbit (eye socket)
The side of the head and extending underneath
The ear canal (shown as a hole on the side of the head behind the upper part of the mandible)
Injuries at these areas will lead to the classical clinical signs that we look for during the Primary Survey, and that are shown in the diagram below right:
Damage to the top of the nose will cause a nose bleed
Damage to the orbit will cause bruising around them (Raccoon eyes)
As the fracture extends along the side of the skull and underneath, CSF will leak out through any hole it can find (usually the nose and the ear canal).
Double vision or deafness, as the fracture line can go through the orbit and the ear canal. These features will only be discernible if the casualty is conscious.
Base of skull fractures are fairly rare, but they are very important because they are prone to major complications. Management is the same as for any skull fracture:
Supportive measures (airway, etc.)
Urgent evacuation
Scalp Wounds
Scalp wounds are damage to the skin and soft tissue over the scalp of the head. They can occur with or without TBI. Due to the good blood flow to the scalp, they can bleed profusely, and this can amount to a significant blood loss in small children. The severity of the bleeding is not related to the presence or severity of underlying brain injury.
It can be difficult to assess and treat scalp wounds if the casualty has a lot of hair.
Beware - A skull fracture with a scalp wound is a compound fracture and infection is possible.
Management
Remove loose visible objects from the wound, but leave embedded foreign bodies in place.
Stop the bleeding by applying pressure to edges of wound using gauze. This can take 15 minutes. Resist the urge to peak after a few minutes to see if bleeding has stopped because it will just start again.
Bandage only after bleeding ceases. If a second bandage is necessary, apply it over the top without removing the first.
Analgesia as required.
If a skull fracture is also suspected, antibiotics may be required, but not always. Therefore, do not give antibiotics but seek medical advice.
Helmet Removal
The key points are shown in the videos below. The aim is to move the head as little as possible during this process.
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