The great majority of head knocks need nothing but observation. The value of a list like this is that it tells you which ones do not, so the rest can be left alone.
Which ones need hospital
The great majority of head knocks need nothing but observation. The value of a list like this is that it tells you which ones do not, so that the rest can be left alone.
Go to hospital, or call 999, if any of these
- Any loss of consciousness, however brief.
- Vomiting more than once after the injury. One episode can be shock; repeated vomiting is not.
- Drowsiness, confusion, or difficulty waking — and any deterioration in alertness from where they started.
- A seizure after the injury.
- Weakness, numbness, difficulty speaking, double vision, or unsteadiness.
- A headache that keeps getting worse, rather than settling.
- Clear fluid or blood from the nose or ears, bruising behind the ears or around both eyes — these suggest a base of skull fracture.
- Amnesia for more than a few minutes before or after the event.
- A dangerous mechanism — a fall of more than about a metre or five stairs, a vehicle, a high-speed sporting collision.
- Anyone taking a blood thinner — an anticoagulant (warfarin, a DOAC), and to a lesser extent the antiplatelet clopidogrel — after any head injury, even a minor one with no symptoms at all. This is the group that talks itself out of going, and the group in which a slow bleed presents twelve hours later.
- Suspected non-accidental injury, intoxication making assessment unreliable, or nobody able to observe them afterwards.
How long to watch, and how
| Period | What to do |
|---|---|
| First 4 hours | The highest-risk window for the bleeds that expand fast. Someone with them, checking every half hour that they are awake, oriented and behaving normally |
| First 24 hours | A responsible adult stays with them, with access to a phone and transport. Sleep is allowed and is not the danger — what is being checked is rousability: that they can be woken and, once woken, respond normally and know where they are. Rouse them, confirm that, and let them settle again. Hourly for the first few hours, then every two to three, including overnight. The purpose is not to keep them awake, and anyone who cannot be roused normally is a 999 call rather than a repeat attempt |
| Days 2 to 3 | Most delayed bleeds that will present acutely have done so. Continue to expect headache and tiredness; do not expect new confusion, drowsiness or weakness |
| Up to 2 to 3 weeks, and occasionally longer | The window for a slow bleed — a chronic subdural haematoma. Higher risk in older people, in anyone on an anticoagulant or antiplatelet, and after heavy alcohol use. The trauma may have been trivial and may have been forgotten |
The subtle signs of a slow bleed, days or weeks later
- A headache that is different, or gradually worsening — particularly one worse on lying flat, on coughing, or first thing in the morning.
- Personality or behaviour change. Flat, irritable, withdrawn, not themselves. This is frequently the first thing a family notices and the last thing anyone attributes to a head injury from a fortnight ago.
- Increasing sleepiness, or being harder to wake than usual.
- Slowed thinking, word-finding difficulty, or new confusion — often mistaken for dementia in an older person, or for depression in a younger one.
- Unsteadiness, a new tendency to fall, or dragging a foot.
- One-sided weakness or clumsiness, however mild.
- New incontinence, which is easy to attribute to anything else.
- In older people, "off legs" or a decline in function with no other explanation. A chronic subdural is a classic cause and it is potentially curable by an operation.
- Any of these means a same-day medical assessment and usually a scan, and the person should say there was a head injury even if it was weeks ago and seemed trivial.
The "talk and deteriorate" pattern is why the first hours matter. A classic extradural bleed can produce a brief knock-out, then a period of being fully lucid and conversational, then rapid decline as the bleed expands. Someone who seems entirely fine an hour after a significant blow has not been cleared by that; they have been observed for an hour.
How to assess someone's state of mind, without any equipment
More useful than it sounds, and better at detecting subtle injury than counting their responses on a formal scale — abnormal alertness, behaviour and cognition pick up mild brain injury that a Glasgow Coma Scale of 15 misses entirely.
- Ask open questions and listen to the shape of the answer, not just its content. Slowed speech, losing the thread, repeating themselves, or answering a different question are all findings.
- Orientation, asked naturally: what day is it, where are we, what time do you think it is, who is this with you. Getting the day wrong by one is common in well people; not knowing where they are is not.
- Test memory of the event itself. What is the last thing you remember before it, and the first thing after? A gap either side — and particularly a gap that is growing when you ask again twenty minutes later — is significant.
- Ask them to repeat something back and again after five minutes. Three unrelated words. Simple, and it detects a great deal.
- Ask somebody who knows them: "is this how they normally are?" The single most useful question available, and the one that catches the person who scores perfectly on everything and is nonetheless not right.
- Re-check rather than check once. A single normal assessment tells you about this minute. The trend across three is what detects a bleed.
Do pupils need checking?
Yes, but understand what they can and cannot tell you.
- What to look for: both pupils the same size, both shrinking briskly when a light is shone in. A pupil that is larger on one side and sluggish or unreactive to light is the important finding.
- It is a late sign, not an early one. An unequal pupil after a head injury generally means pressure is already being exerted on the brainstem. By the time it appears, the person is usually obviously deteriorating in other ways — so pupils confirm an emergency rather than detect one.
- Around one person in five has slightly unequal pupils normally, and eye drops, previous eye surgery, an artificial eye and some medicines all change the response. A difference without a baseline means much less than a change you have watched happen.
- Do not wait for it — but act the moment you see it. Alertness, behaviour, orientation and the trend across repeated checks all move earlier and matter more, so pupils should never be what you are waiting on. If a new pupil asymmetry does appear, that is a 999 call immediately — not something to recheck in ten minutes, and not something to weigh against how well the person otherwise seems. If pupils are the abnormality that finally prompts the call, the call is late; if they appear and nothing happens, it is later still.
- Do not let them "sleep it off" unobserved — but sleep itself is not dangerous. The old advice to keep someone awake all night is wrong. Someone can sleep provided a responsible adult can rouse them and check they respond normally.
- Concussion is a brain injury and the return-to-play rules exist for a reason. The danger is a second impact before the first has resolved. In UK grassroots sport the guidance is if in doubt, sit them out, and no return to play on the same day for anyone.
- Suspected spinal injury: do not move them, do not remove a helmet, keep the head still and call 999.
Burns and scalds
Cool running water, twenty minutes
Not five, not "until it feels better". Twenty minutes of cool — not ice-cold — running water, and it remains worth doing up to about three hours after the injury. This single step reduces depth, reduces the need for surgery and reduces scarring more than anything done later in hospital.
Remove clothing and jewellery, unless it is stuck
Swelling comes fast, and rings and watches become tourniquets. Anything stuck to the burn stays where it is.
Cover with cling film, loosely
Laid lengthways, not wrapped around a limb, so it cannot constrict as swelling develops. It is sterile inside the roll, it does not stick, and it lets the burn be seen without disturbing it. A clean plastic bag works for a hand or foot.
Keep the rest of them warm
Cooling a burn cools a person, and hypothermia is a real risk in a child or in a large burn. Cool the burn, warm the patient.
What not to put on it, and why the myths persist. No ice or iced water
— it causes further injury by vasoconstriction and deepens the burn. No butter, oil, cream,
toothpaste or flour: they hold heat in, introduce infection and have to be scrubbed off later,
which is far worse than the burn. No burn gels or dressings instead of cooling —
they are for afterwards, and a gel applied at two minutes usually means the twenty minutes of water
never happened. And do not break blisters.
Which burns need medical assessment
- Anything larger than the person's own palm, roughly.
- Any burn to the face, hands, feet, genitals, or across a joint, regardless of size.
- Any circumferential burn — right around a limb, finger or the chest.
- All full-thickness burns — white, brown, leathery or charred, and often painless, because the nerve endings have gone. Painlessness is a bad sign, not a good one.
- All chemical and electrical burns, and any burn with inhalation — soot around the nose or mouth, a hoarse voice, singed nasal hairs. Airway swelling after smoke inhalation can develop over hours and is a 999 call.
- Any burn in a child, an older person, or anyone whose burn does not fit the story. Scalds in children are the commonest presentation of physical abuse, and a burn that does not match the account given is a safeguarding matter.