Head injury: which warning signs need urgent attention?

Short answer. After a blow to the head, vomiting, difficulty waking the person, a seizure, weakness in an arm or leg, unusual speech, increasing confusion or a worsening headache should prompt an immediate call to emergency services. This preserves the level of urgency in the French public guidance used here. Even without loss of consciousness, some symptoms or risk factors require medical advice.

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

Important. This guidance helps you recognise a worrying situation; it does not allow you to decide for yourself that an injury is minor. It cannot replace a medical examination or the instructions given by the emergency department.

When should you call emergency services immediately?

After a recent blow to the head, call emergency services if you notice any of these changes:

• The person loses consciousness, does not regain normal alertness or becomes difficult to wake.

• They have a seizure.

• An arm, a leg or one side of the face suddenly seems weaker; speech becomes difficult or coordination deteriorates.

• They become very confused, no longer recognise people close to them, speak incoherently or show a marked change in behaviour.

• Vomiting starts after the injury, or a headache gets worse and does not go away.

• One pupil looks markedly different from the other, or new visual problems appear.

Do not wait for several signs to appear. One serious warning sign is enough to seek emergency help. The criteria above are not a screening test and cannot tell you at home whether a CT scan is needed.

When you call, say straight away that there has been a head injury and describe what you have noticed. Follow the call handler’s instructions, particularly about moving the person if a neck injury is possible.

What if the person is awake and seems well?

Not losing consciousness does not rule out a concussion or another injury. Headache, nausea, dizziness, and problems with attention or memory may appear immediately or later. These do not all mean there is a life-threatening emergency, but they warrant assessment according to the circumstances. In France, any vomiting after the injury warrants an immediate call to emergency medical services for advice on the appropriate care.

Seek prompt medical advice after a head injury if the person lost consciousness, has gaps in their memory around the accident, has vomited, has a persistent headache or develops unusual symptoms. Also report anticoagulant or antiplatelet medication, a bleeding disorder, older age, previous brain surgery or a significant accident mechanism: these factors can affect the level of concern and medical decisions.

This advice does not replace individual guidance on where and how urgently to seek care. In France, emergency medical services can help if you are unsure about the urgency.

Why do the following hours matter?

A sign may be subtle at first, then develop or become more pronounced. Ask not only how the person feels now, but whether their condition is changing. Increasing drowsiness, new vomiting or unusual behaviour must be reported immediately.

If the emergency department has discharged the person home, follow the written discharge instructions, the monitoring arrangements and the plan for seeking help if their condition worsens. The duration and conditions of observation depend on the assessment: there is no universal home rule that can replace this advice.

Do not rely on outward appearance. A small bump may cause unnecessary alarm, while the absence of a wound does not rule out an internal problem. The circumstances, examination and changes over time matter more than the appearance of the skin.

What information should you prepare for the healthcare professional?

A very short note is enough. If you can, record:

• When and how it happened: approximate time, fall, collision, sport, and height or speed if known.

• The person’s condition straight afterwards: apparent loss of consciousness, confusion, gaps in memory and initial symptoms.

• What has changed: new vomiting, increasing pain, behaviour, balance, speech and alertness.

• Relevant medical details: medication, especially anticoagulants, known conditions and medical history.

This information helps describe the situation. Gathering it must never delay an emergency call when there is a serious warning sign.

A common question: does a normal CT scan rule out concussion?

No. CT scans mainly look for certain complications, such as bleeding; concussion can cause symptoms without any visible abnormality on a CT scan. Whether imaging is needed is a decision for the healthcare professional, based on the examination and risk factors.