• Tim

Head Injury

Updated: Apr 26, 2021

Head injuries are one of the most common traumatic injuries. Usually they're nothing to worry about, but occasionally they can lead to concussion or even be fatal. Read on to learn the first aid for different types of head injuries...


Around 1.4 million people attending hospital emergency departments in England and Wales as a result of a head injury every year. Up to half of these are children and around 14% are admitted for a hospital stay. Only 20% of those admitted have features of a skull fracture or brain injury. Only about 0.2% (2,800 people) die as a result of their head injury.


The brain is very soft, with a consistency similar to jelly. It is surrounded by cerebro-spinal fluid (CSF), a straw coloured liquid that helps to cushion it and provide a constant environment. The brain and CSF are surrounded by meninges (as in meningitis!), which further protect them. The skull and skin provides protection from the outside world.

There are lots of blood vessels in the brain, responsible for supplying the significant amounts of oxygen and glucose required to power the 100 billion cells, as well as removing the waste products. Blood vessels in the brain have an extra layer to them, to prevent pathogens crossing the blood-brain barrier.

Head injury components

When I'm assessing a head injury, I think about 3 interrelated components, with each giving a clue to the likelihood of the others. I'm trying to work out the damage to the...

  • Brain (the important bit)

  • Skull (the protective box)

  • Neck (the vulnerable bit that supports this huge weight ~ 5kg!)

This post will look at the brain and skull injuries. Neck injuries will be covered in a later post about spinal injuries.

Brain injury

If someone has received a blow to the head, I'm trying to work out if they've got:

  • No brain injury (hopefully)

  • A concussion (or mild traumatic brain injury (TBI)), or

  • A compression (or severe TBI)

Damage can occur from the initial injury, or it can occur as a result of problems that follow on from the injury. These are referred to as primary and secondary injury consecutively. This later damage often results from unconsciousness or a blocked airway, which leads to a lack of oxygen and a build up of carbon dioxide. You can read more about how to prevent it in this post about unconsciousness.


Concussion, or mild TBI is what happens to the brain when it's shaken. Symptoms can come on immediately, or may be delayed, and last from a few minutes to a couple of years at worst. Symptoms include:

  • Being knocked out

  • Confusion or drowsiness

  • Loss of coordination

  • Nausea or vomiting

  • Headache

  • Change of behaviour (especially in children)

  • Memory loss

  • Visual problems (such as "double vision')

Whilst concussion is a 'minor' injury, it is still significant. Recent research suggests that repeated concussions, and a new concussion whilst still experiencing symptoms of a previous concussion can do permanent damage to the brain. This has been linked to conditions such as Alzheimers, with some groups of older people who have had repeated concussions being 3 times more likely to get the disease.

More importantly though, if someone has sustained a concussion, then they should be checked out by a healthcare professional, as they're also at risk of developing a compression injury.


In a compression injury, damaged blood vessels and swelling in the brain increase the pressure inside the skull, pressing on the brain itself. When this happens, the body will initially respond by shunting some of the CSF out and trying to increase the pressure produced by each heart beat.

However, when these mechanisms run out, the blood will be squeezed out of the brain, which will result in a loss of consciousness. If the pressure increase continues, the brain itself will be squeezed out through the only significant hole, where the spinal cord leaves the skull. When this happens, the cerebellum will be compromised, which normally carries out vital life support functions such as breathing and heart beat.

If someone is developing a compression injury, their level of consciousness is likely to decline and their eyes may eventually become unequal or slow to react, as pressure is applied to the optic nerves. Learn more about what to do if someone is unconscious in this post. They could also have a seizure - see this post to find out what to do.

There are also groups of people who are at higher risk, so particular care should be taken with people who:

  • Are older

  • Have bleeding or clotting disorders

  • Are on 'blood thinners' or anticoagulants, such as warfarin

  • Are intoxicated

  • Live alone

If you suspect a compression injury is possible, you should call 999 for an ambulance immediately.

Skull Injury

The injury to the skull can also be minor or severe.

Skull Fracture

It is likely that anyone with a skull fracture may also have a serious brain injury. The signs of a skull fracture are:

  • Any deformity, such as a ridge or soft part of the skull

  • CSF leaking from the ear or nose (likely to be pink due to blood and CSF mixing)

Later signs include 2 black eyes in the absence of facial trauma (racoon eyes) and bruising behind the ears (Battle's sign).

If CSF is fluid leaking from the ear or nose, you can minimise the risk of infection of the brain by lightly covering it with a clean dressing. Take care not to stop the fluid coming out as the drainage will help combat any increase in pressure.

Minor Injury

Minor injuries such as small lacerations and 'eggs' on the head should be treated as such.

The scalp has a lot of blood vessels in it, so bleeds a lot when it is damaged. Any bleeding can be managed as usual, using direct pressure. Often, a bandage held in place by the patient is the easiest and most successful option.

An 'egg' is simply the body's normal response to insult or injury. Swelling occurs as the blood vessels become leaky to allow immune cells to repair the damage.


If someone has sustained a head injury, look for signs of concussion, compression or skull fracture. If any of these are detected, you should seek appropriate help from a healthcare professional.

If you want to learn more about what to do if someone has sustained traumatic injuries, why not book one of our first aid courses.