Head injuries are one of the most common reasons people end up in an emergency department — a knock on the pitch, a fall on the stairs, a car accident. Most of them are minor and settle on their own. The problem is that a small proportion are not minor, and the signs that separate the two are not always obvious in the first hour.
This article explains when a blow to the head needs medical assessment, when it is an immediate emergency, and what to watch for in the hours and days that follow.
What do "head injury" and "concussion" mean?
Head injury is a broad term covering any harm to the head — from a bruise to the skin, to a skull fracture, to bleeding inside. Concussion is one form of it: a temporary disturbance of brain function after a blow or sudden movement of the head, and it usually does not show up on imaging.
An important point: loss of consciousness is not required. Most concussions happen without any loss of consciousness at all, so a knock someone "walked off" is not necessarily harmless.
Signs that mean go to the emergency department now
Any of these after a head injury is an immediate emergency:
- Loss of consciousness — even for seconds.
- Repeated vomiting (twice or more).
- A severe headache, or one that worsens rather than settles.
- Seizures.
- Weakness or numbness on one side, or difficulty speaking.
- Double vision, or pupils of unequal size.
- Clear fluid or blood from the nose or ear.
- Heavy drowsiness or difficulty waking the person.
- Confusion, not knowing where or when they are, or unusual behaviour.
- Obvious loss of balance or inability to walk.
Situations needing urgent assessment even with mild symptoms
Some circumstances make an apparently minor knock worth immediate attention:
- The person takes blood thinners or anticoagulants — the single most important factor. Bleeding can follow even a light injury.
- Older people — vessels are more prone to tearing, and bleeding can appear late.
- Children under two.
- A fall from height, a high-speed accident, or injury from a solid object.
- A clotting disorder, previous brain surgery, or a shunt for hydrocephalus.
- Alcohol or anything else that makes assessing consciousness unreliable.
Children — slightly different signs
Young children can't describe what they feel, so watch for:
- Persistent crying that won't settle, or a clear change in mood.
- Refusing food or feeding.
- Repeated vomiting.
- Unusual sleepiness outside their normal sleep time.
- Swelling or a bulge at the site of the knock, especially in infants.
- Not using an arm or leg normally.
Any one of these after a head injury warrants medical assessment — and children under two need a lower threshold for caution.
What to do — and what not to do
Do:
- Stop all sport or exertion immediately — do not carry on playing.
- Keep the person calm and observed, particularly for the first 24 hours.
- Apply a cold compress to the bruised area to reduce swelling.
- Tell the medical team about any blood thinners, and the details and timing of the injury.
- Sleep at the normal time is not forbidden — but someone should be able to rouse them and confirm their responses are normal.
Do not:
- Give any painkiller on your own initiative — some medications increase bleeding risk. Any medication should be on a doctor's instruction.
- Return to sport or exertion the same day, even if you feel fine.
- Move the person forcefully if a neck injury is suspected — stabilise the head and neck and call an ambulance.
- Rely on "he seems fine" in the first hour — some complications appear later.
When is a brain scan needed?
Not every head injury needs imaging. The decision follows a clinical examination and an assessment of risk factors, and leans towards scanning where there was loss of consciousness, repeated vomiting, neurological symptoms, blood-thinning medication, a high-force injury, or older age.
A CT scan is the main test in the acute phase because it shows bleeding and fractures quickly. At Town Hospital the emergency department and imaging operate 24 hours a day, so assessment and scanning happen in the same place without delay.
Delayed bleeding — the part people miss
Some types of bleeding — particularly subdural haemorrhage — can collect slowly and appear days or weeks after the injury. This is more common in older people and those taking blood thinners.
So if a gradually worsening headache, drowsiness, a change in behaviour or memory, or weakness on one side appears after a head injury, go to the emergency department — even if the injury was a while ago and seemed minor at the time.
Symptoms after a concussion
Symptoms can persist for a period after a concussion, including headache, dizziness, fatigue, difficulty concentrating, sensitivity to light or noise, and changes in mood or sleep. Most improve gradually with rest and a staged return to activity, but symptoms that persist or worsen warrant medical review.
Return to sport should be gradual and medically cleared — a second injury before full recovery is considerably more dangerous.
Frequently Asked Questions
My child hit their head and has no symptoms — should we go to the emergency department?
If none of the warning signs above are present and the child is behaving, eating and playing normally, observation at home for 24 hours is usually enough. But if they are under two, the fall was from height, or any warning sign appears — go immediately.
Can they sleep after a knock to the head?
Yes. Sleeping at the normal time is not forbidden, and the old advice to "keep them awake" is not accurate. What matters is that someone can rouse them and confirm their responses and speech are normal. If they are difficult to wake, that is a warning sign requiring emergency care.
Does a concussion show on a scan?
Usually not. Concussion is a clinical diagnosis based on symptoms and examination; imaging is done to rule out bleeding or a fracture, not to confirm the concussion itself.
I take blood thinners and had a light knock — can I wait?
No. Get assessed straight away and say that you take blood thinners. In people on anticoagulants a light injury can cause bleeding, and early assessment matters.
Is a headache after a knock normal?
A mild headache that improves gradually is common after a minor injury. But a headache that worsens rather than settles, or comes with vomiting, drowsiness or neurological symptoms, is not normal and needs immediate assessment.
When can I return to sport?
After symptoms have fully resolved and with medical clearance, returning in graded stages. Going back early, before full recovery, raises the risk of a more severe second injury.
Neurosurgery consultation
If you need a specialist opinion after a head injury, or you have persisting symptoms after a concussion, you can book with Dr Ahmed El Ghannam, Neurosurgery Consultant at Town Hospital, or with the neurosurgery team. For emergencies, Town Hospital's emergency department and imaging are available 24 hours — Fifth Settlement, New Cairo. Hotline 15276.
This article is for general awareness and does not replace medical advice. If any warning sign is present after a head injury, go to the emergency department immediately.