When should you seek medical care after a head injury?

Emergency numbers
United States: 911
United Kingdom: 999 or 112
European Union: 112
Elsewhere: your local emergency number

Short answer. A head injury warrants urgent assessment if there are neurological signs or the person’s condition is worsening. Even without dramatic signs, loss of consciousness, amnesia, a persistent headache or taking anticoagulants requires prompt medical advice to determine the appropriate care. The absence of a bump or loss of consciousness is not enough to be reassuring. If vomiting occurs after the injury, contact emergency services immediately, in keeping with the French public guidance used here.

Important. After a blow to the head, a person who is difficult to wake, has a seizure, has weakness on one side of the body, speaks abnormally or becomes increasingly confused needs emergency help: call emergency services immediately. This article cannot assess the severity of an injury remotely.

Three situations requiring different decisions

The first question is not how painful the impact was, but what has happened since. The same accident needs to be assessed differently in someone who is gradually improving and someone who is becoming less attentive, more drowsy or unusual in their responses. The circumstances and medication also matter. The UK’s NICE guidelines distinguish signs requiring immediate emergency assistance from those warranting assessment in an emergency department.

1. Call emergency services immediately

Call emergency services if the person is unconscious or difficult to wake, has a seizure, weakness or loss of sensation in a limb, new difficulty speaking, increasing confusion, vomiting after the injury or a headache that is worsening and does not go away. One pupil being markedly larger than the other after an injury is also a warning sign. Do not delay the call to finish reading or see whether other signs appear.

If the impact may have injured the neck, avoid moving the person unnecessarily and follow the emergency team’s instructions. These signs do not all mean a complication is present, but they do mean you must not wait.

2. Seek prompt medical assessment even if the person seems well

Loss of consciousness, even if it has ended, a gap in memory around the accident or a persistent headache must be reported promptly to a healthcare professional. A forceful impact, previous brain surgery, a bleeding disorder or taking an anticoagulant or certain antiplatelet medicines also affects the appropriate care pathway. Do not decide for yourself whether a CT scan is needed from a list found online.

For example, someone falls, gets up and speaks normally, but cannot remember the minutes before the fall. Seeming well does not cancel out the amnesia. They need an appropriate assessment.

In a child, especially a very young child, unusual behaviour, marked irritability or difficulty feeding after a head injury calls for particular vigilance. Examination and imaging criteria differ from those for adults: healthcare professionals assess them.

3. Monitor at home only when this has been judged appropriate

Home monitoring is not an improvised test to avoid a consultation. It depends on prior assessment or guidance, instructions on when to seek further care, and someone able to recognise deterioration. NICE guidelines specifically require written instructions at discharge from the emergency department and home circumstances that allow appropriate supervision.

Do not decide to keep someone awake all night as a matter of principle: instructions about sleep and monitoring depend on the assessment they have received. However, new difficulty waking the person is an emergency warning sign.

What should you say on the phone or at the consultation?

You can gather these four pieces of information without delaying the call:

1. The impact: approximate time, fall or accident, mechanism and any possible neck impact.

2. The person’s condition immediately afterwards: loss of consciousness, confusion, amnesia or unusual behaviour.

3. Changes since then: headaches, vomiting, drowsiness, balance or speech problems, and especially anything getting worse.

4. Medical context: age, anticoagulants or antiplatelet medicines, bleeding disorders and relevant medical history.

Describe what you actually observed, even if the information is incomplete. Saying that someone seemed fine an hour ago but is now becoming difficult to wake is more useful than drawing your own conclusion about how serious the injury is.

What if symptoms appear the next day?

Some concussion symptoms may be felt immediately; others may appear hours or days later. A delayed onset is therefore no reason to ignore them. If a warning sign appears, contact emergency services; if symptoms persist or interfere with everyday life, discuss them with a healthcare professional.

The aim is to get the right care at the right time, without dismissing the injury or assuming that every headache necessarily requires a CT scan.