Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
1
Is any of this happening now?
Call 911
Call emergency services after a head injury if you or someone else develops:
Loss of consciousness or difficulty waking
Increasing confusion, agitation, or unusual behaviour
New weakness, numbness, facial drooping, or speech difficulty
A seizure
Repeated vomiting
A severe or rapidly worsening headache
Unequal pupils, worsening vision, or loss of coordination
Clear fluid or blood coming from the nose or ears
Emergency assessment is also appropriate for new neurological symptoms even when there is no remembered injury.
Do not drive yourself if you are confused, weak, very sleepy, or having vision problems.
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
Someone who has chest pain, tightness or pressure lasting more than a few minutes
Someone who has sudden weakness or drooping on one side of the face or body, slurred speech, or sudden confusion
Someone who is unconscious, or cannot be woken
Someone who is bleeding heavily and it will not stop with firm pressure
Someone who has had a seizure that will not stop, or does not wake up afterwards
Someone who has lips or skin that look pale, blue, grey or blotchy
Someone who you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Seek prompt medical advice after a head injury if you take a medicine that reduces blood clotting, have a bleeding disorder, or develop a persistent headache or gradual change in balance, memory, or behaviour.
Returning or worsening neurological symptoms require urgent assessment rather than waiting for the next appointment.
3
Does any of this apply?
Book an appointment
After treatment, attend planned follow-up for stable recovery questions, wound checks, medicine review, and rehabilitation.
Every sign above is quoted from the sofidex article on Subdural hematoma. If you are not sure, err upward — it is always reasonable to be checked.