Most strokes are recognised by the person themselves or by whoever is with them, minutes before any clinician is involved, and the quality of that recognition decides what treatment is still possible by the time they arrive. This chapter is about the recognition, the strokes that public campaigns miss, and the one fact that the hospital cannot reconstruct without you.
1. FAST, and what it catches
Face drooping on one side, Arm weakness or drift, Speech slurred or jumbled or absent, Time to call 999. It is the right public message and it should stay the public message: it is easy to remember, and it catches most strokes in the front two-thirds of the brain, which is where most strokes are. Any one of the three signs is enough.
2. The strokes it misses
Roughly one stroke in five is in the back of the brain: the brainstem, the cerebellum and the occipital lobes, supplied by the vertebral and basilar arteries. These present with none of the FAST signs, and they are the strokes most often sent home from an emergency department. The extra signs are sometimes taught as BE-FAST:
- Balance. Sudden vertigo (the room spinning), unsteadiness, or an inability to walk in a straight line or stand without support.
- Eyes. Sudden double vision, loss of half the visual field, or loss of vision in one eye (which can also be a warning of a carotid problem).
- Plus: sudden difficulty swallowing, hiccups that will not stop, numbness of one side of the face and the opposite side of the body, and a sudden violent headache with vomiting.
3. It is sudden onset, not age, that matters
Around a quarter of strokes occur under the age of 65, and a young person with sudden focal symptoms is routinely told it is a migraine, anxiety or a trapped nerve. The feature that distinguishes a stroke is that it is sudden and focal: one function, on one side, from one moment. Migraine aura spreads over minutes and usually has a history. A seizure is followed by confusion. A faint recovers in seconds. None of that reasoning is safe to do at home; it is the reasoning the stroke team does after the scan.
4. TIA: the warning that is treated as an emergency
A transient ischaemic attack is a stroke whose symptoms resolve, usually within an hour, because the blockage cleared itself. It is not a lesser event. The risk of a completed stroke in the days after a TIA is high — historically around one in twenty in the first week — and it is cut sharply by immediate assessment and treatment. Both UK and US guidance now treat a TIA as a same-day emergency: aspirin 300 mg immediately unless contraindicated, specialist assessment within 24 hours, imaging of the brain and the neck arteries, and for high-risk TIA two antiplatelets for three to four weeks. The old habit of scoring a TIA and seeing low-risk ones in a week has gone from UK guidance: every TIA is seen within 24 hours.
If the symptoms have gone, still call. Ring 999 while they are present; if they have resolved, ring 111 or go to A&E the same day and say "I think I have had a TIA". Do not wait to see the GP tomorrow.
5. The mimics
About a quarter of people brought in as a possible stroke turn out to have something else, and that is the system working. The commonest are a seizure with weakness afterwards, low blood sugar (which is why the ambulance crew check a finger-prick glucose), migraine with aura, a functional neurological disorder, an old stroke made worse by an infection or dehydration, a brain tumour, and Bell's palsy (which affects the whole side of the face including the forehead; a stroke usually spares the forehead). None of these should be diagnosed at the scene. The cost of a false alarm is a scan; the cost of a missed stroke is the window.
6. Last known well: the fact only you can supply
Every treatment in the clock chapter is measured from the last moment the person was definitely normal, and that moment is usually known only to whoever was with them. Write it down. If they were found, the time is when they were last seen normal, not when they were found. If they woke with it, the time is when they went to sleep, and the hospital will use a scan to decide whether the stroke is fresh enough to treat. "About an hour ago" is a treatment decision; "I'm not sure" can close a window that was open.
7. What to do while waiting
The full first-minutes sequence is the emergency chapter. In short: 999 and say "stroke"; fix the time; nothing by mouth, no aspirin; sit or lie them with the head slightly raised, recovery position if drowsy; gather the medicines, especially any blood thinner, and the history of surgery, bleeding or atrial fibrillation; and do not delay for observations except a finger-prick glucose.
8. Stroke in children
Rare, missed more often than in adults, and for the first time covered by the 2026 American guideline. Children present with the same sudden focal signs; the common causes are different (heart disease, sickle cell disease, arterial dissection, infections and inflammation of the arteries), and the mimics are more common. The guideline supports thrombolysis and thrombectomy in selected children at centres with the expertise, and says the priority is recognition: a child with a sudden one-sided weakness or speech loss needs the same 999 call and the same clock as an adult. The UK has a separate paediatric stroke guideline from the Royal College of Paediatrics and Child Health; the two agree on the essentials.
9. Where UK and US guidance differ
On recognition, not at all: both use FAST publicly and BE-FAST clinically, both treat TIA as a 24-hour emergency, and both say MRI for diagnostic uncertainty. The US guideline goes further on what the ambulance does with the recognition: it endorses pre-hospital stroke-severity scoring to identify likely large-vessel occlusions and take them straight to a thrombectomy centre, and mobile stroke units with a scanner on board. In the UK the pre-alert goes to the nearest hyperacute stroke unit and the transfer happens from there.