Stroke is the one emergency where the treatment available depends almost entirely on the clock, and where the single most valuable thing anybody at the scene can supply is not a measurement but a time.
1. Recognising it
FAST — Face drooping, Arm weakness, Speech difficulty, Time to call 999 — is the public message and should stay it. It catches most strokes in the front of the brain.
It is close to blind to the roughly one stroke in five that affects the back of the brain. Those present with sudden vertigo, unsteadiness, double vision, difficulty swallowing, slurred speech, vomiting or a violent sudden headache, and get attributed to labyrinthitis, migraine or alcohol. The additional signs are sometimes taught as BE-FAST: sudden Balance loss and Eye or vision change added to the front. Anyone with sudden vertigo who cannot walk unaided is having a stroke until proven otherwise.
And age is not a filter. Around a quarter of strokes occur under 65, and a young person with sudden focal symptoms is routinely told it is a migraine. Sudden onset is the feature that matters, not the patient's age.
2. What to do in the first minutes
999, and say “stroke”
It changes the response and triggers a pre-alert. Note the time of the call.
Fix the time they were last known well
Ask whoever saw them. Write it down. This is the single most useful piece of information you can hand over and it decides which treatments are on the table.
Nothing by mouth — no food, no drink, no tablets
Swallowing is impaired in a large proportion of strokes and aspiration is a major cause of avoidable harm afterwards. And no aspirin: about one stroke in seven is a bleed, and aspirin makes that worse. The distinction needs a scan.
Sit or lie them comfortably, head slightly raised, and stay
Recovery position if drowsy or vomiting. Loosen tight clothing. Keep them warm.
Gather the medicines and the history for the crew
Especially anticoagulants — warfarin, a DOAC — which change both the treatment and the reversal needed, along with recent surgery, bleeding, seizures and known atrial fibrillation.
Do not delay for observations
A blood pressure or a glucose reading is useful for the handover but never at the cost of minutes. The one exception worth the thirty seconds is a finger-prick glucose, because hypoglycaemia mimics stroke exactly and is reversible — see the collapse chapter.
3. The scan comes first, because there are two different diseases
| Ischaemic — a blockage | Haemorrhagic — a bleed | |
|---|---|---|
| Proportion | About 85% | About 15% |
| Aim of treatment | Reopen the artery | Stop the bleeding and control the pressure |
| Treatments | Thrombolysis, thrombectomy, then antiplatelets | Blood pressure lowering, reversal of any anticoagulant, sometimes neurosurgery |
| Consequence of guessing wrong | — | Thrombolysis given to a bleed is catastrophic, which is why nothing happens before a CT scan and why nobody should be given aspirin at home |
4. Ischaemic stroke — the treatments and the clock
Thrombolysis, within 4.5 hours
A drug given intravenously to dissolve the clot: alteplase, or increasingly tenecteplase.
Which drug should be first choice, and the answer is not the one the outcome data gives
- On outcomes, they are the same. In the AcT trial, 36.7% of tenecteplase patients were free of significant disability at 90 days against 35.9% on alteplase — odds ratio 1.03 — with identical symptomatic bleeding at 3.2% against 3.1%. ATTEST-2 confirmed non-inferiority and did not show superiority. Reteplase, in a separate trial, was also no different.
- So the choice is decided by logistics, and logistics decide outcomes here. Tenecteplase is a single bolus over about five seconds; alteplase is a bolus followed by a one-hour infusion. Given that the odds of a good outcome fall from 2.55 to 1.34 across the window, a drug that removes an infusion pump from the process — and with it the delay in starting, the delay in moving the patient, and the complication of transferring someone mid-infusion to a thrombectomy centre — converts directly into outcome.
- So: tenecteplase 0.25 mg/kg, to a maximum of 25 mg, as the practical first choice, with alteplase entirely acceptable where that is what a unit uses. This is the rare case where two drugs are equivalent in trials and one is clearly better in a hospital.
- And the genuine first choice for a large vessel occlusion is neither. It is thrombectomy, with a thrombolytic given alongside if the patient is eligible and it will not delay the procedure.
How much difference does an hour make? A great deal.
The pooled analysis of the alteplase trials gives this directly, as the odds of being free of significant disability at three months compared with no thrombolysis:
| Treated within | Odds of a good outcome | Reading |
|---|---|---|
| 0–90 minutes | 2.55 (1.44–4.52) | Two and a half times the odds. This is the prize, and almost nobody gets here |
| 91–180 minutes | 1.64 (1.12–2.40) | Still substantial. Roughly a third of the benefit already gone |
| 181–270 minutes to 4.5 hours | 1.34 (1.06–1.68) | Real, and about half of what it was in the first 90 minutes |
| 271–360 minutes | 1.22 (0.92–1.61) | No longer statistically significant. This is why the window closes at 4.5 hours |
Which is the whole argument for calling 999 immediately rather than waiting to see. Every minute between symptom onset and the needle is spent from a fixed budget, and most of that budget is consumed before anyone reaches hospital — by the wait to call, the wait to be seen, and the wait to be scanned.
- The main risk is bleeding into the brain. Large parenchymal haemorrhage in about 5% of treated patients against 1% of untreated. Early deaths rise; overall mortality at three to six months does not.
- Many people are not eligible — recent surgery, active bleeding, anticoagulation, very high blood pressure, a large established infarct, or simply arriving too late. Ineligibility is common and is not a judgement about how serious the stroke is.
Thrombectomy, within 6 hours and sometimes to 24
Mechanical removal of the clot through a catheter, for a large vessel occlusion — a blockage in one of the major arteries. It is the single most effective treatment in ischaemic stroke and it is only available at specialist centres, which is why the pre-alert and the destination matter.
- Standard window is 6 hours, extending to 24 hours in selected patients where imaging shows brain tissue still salvageable.
- It can be done after thrombolysis, and it can be done where thrombolysis is contraindicated.
- Risks include vessel injury, bleeding and clot fragments moving to a new territory. The absolute benefit in eligible patients is nonetheless large.
Beyond 4.5 hours — where the evidence is genuinely unsettled
- TIMELESS gave tenecteplase to patients most of whom also had thrombectomy: no better than placebo. Symptomatic bleeding 3.2% against 2.3%; mortality 19.7% against 18.2%.
- TRACE-III gave tenecteplase to patients with large vessel occlusion who could not access thrombectomy: 33.0% were free of disability at 90 days against 24.2% on standard care. Bleeding rose from 0.8% to 3.0%; mortality was unchanged at about 13%.
- HOPE, using alteplase, found more bleeding — 3.8% against 0.5% — with no mortality difference.
What that adds up to, in absolute terms. On the TRACE-III figures, roughly 11 people would need treatment for one extra person to be free of disability, and roughly 45 would need treatment for one extra symptomatic brain bleed. That is a favourable trade for someone facing severe disability, and it is a real trade rather than a free one. It also depends on being in the group those trials studied: large vessel occlusion, salvageable tissue on imaging, and no thrombectomy available. Contested for the late window as a whole; Strong within 4.5 hours.
5. Haemorrhagic stroke
- Blood pressure lowering, promptly and carefully, as part of a care bundle that improves outcomes.
- Reversal of anticoagulation, urgently, where relevant: prothrombin complex concentrate and vitamin K for warfarin, specific reversal agents for the DOACs. This is the reason the medicine list matters at the scene.
- Neurosurgery for some — a large bleed with pressure effects, a cerebellar bleed, or hydrocephalus needing drainage. Many bleeds are not operable and are managed medically.
- Tranexamic acid is not standard: the large trial in intracerebral haemorrhage did not show a benefit on outcome.
- Subarachnoid haemorrhage is a distinct entity — a sudden, worst-ever “thunderclap” headache, often with neck stiffness and vomiting. It needs a CT, often a lumbar puncture if the CT is negative and suspicion remains, and treatment of the aneurysm by coiling or clipping.
6. When you are being asked to decide and you do not know what to say
Five questions that get you the information you actually need
- “Is this a bleed or a blockage?” Everything follows from it, and the scan has already answered it by the time anyone is asking you to consent.
- “What is the chance of benefit, and the chance of harm, in numbers?” Ask for both as absolute figures, not percentages of a percentage. “About one in ten do better, about one in forty-five have a brain bleed” is a sentence a stroke team can give you.
- “What happens if we do nothing?” The comparison is never treatment against health; it is treatment against the natural course of this stroke, which may be severe disability.
- “Is there a time limit on deciding?” Usually yes, and knowing whether you have five minutes or thirty changes how much you can reasonably deliberate.
- “Would you offer this to your own relative?” Blunt, and it works. It asks a clinician to summarise a judgement rather than a dataset.
Two things worth knowing before you are in the room. Stroke teams offer thrombolysis because the average patient like this does better with it, not because they are certain about the individual in front of them — uncertainty is normal and saying so is not a warning sign. And declining a treatment is a legitimate choice, particularly for someone very frail or with limited life expectancy, where the balance genuinely shifts. If the person cannot decide for themselves and there is no advance decision or attorney, the team decides in their best interests, and family are consulted about what the person would have wanted rather than asked to consent.
7. Finding out why it happened
This is where a stroke admission earns most of its long-term value, and it is the part most often left half-finished. A stroke without a cause identified is a stroke waiting to repeat.
| Test | Looking for |
|---|---|
| CT, then MRI in many cases | Type, territory, size, age of the lesion |
| Carotid imaging — ultrasound, CT or MR angiography | Narrowing of the carotid artery. Time-critical, because surgery for symptomatic severe stenosis is most effective within the first two weeks |
| ECG, then prolonged cardiac monitoring | Atrial fibrillation, and this is the one most often missed. A single ECG finds a minority of paroxysmal AF; monitoring for days to weeks finds substantially more, and the finding changes treatment from an antiplatelet to an anticoagulant |
| Echocardiogram | Cardiac source of embolism, valve disease, and in younger patients a patent foramen ovale |
| Bloods | Full blood count, glucose and HbA1c, full lipid profile, kidney and liver function, clotting, and inflammatory markers |
| In younger patients, or where nothing is found | Thrombophilia and antiphospholipid screen, vasculitis markers, arterial dissection on imaging, and Lp(a) — a once-in-a-lifetime test that is frequently omitted and is exactly the kind of unexplained-stroke finding it exists for. See the genetics chapter |
| Swallow assessment | Within hours, before anything is given by mouth |
8. Preventing the next one
The risk of a further stroke is highest in the first days and weeks, which is why secondary prevention starts in hospital rather than at a follow-up appointment.
| Intervention | Detail |
|---|---|
| Antiplatelet, or anticoagulant if AF | After an ischaemic stroke: aspirin initially, then usually clopidogrel long term. In minor stroke and high-risk TIA, a short course of two antiplatelets for a few weeks reduces early recurrence, then one. If atrial fibrillation is found, an anticoagulant replaces the antiplatelet — a DOAC in most cases — and that substitution is one of the highest-value decisions in the whole pathway |
| Lipid lowering | A high-intensity statin, with ezetimibe and then a PCSK9 inhibitor added if the target is not met. The apoB argument in the heart guide applies directly here |
| Blood pressure | The single largest modifiable contributor. Treatment usually starts or intensifies within days, not immediately, and the target is lower than many people expect — see the blood pressure chapter. Home monitoring is worth establishing early |
| Carotid surgery | For symptomatic severe narrowing, ideally within two weeks. The benefit falls sharply with delay |
| Diabetes and glucose | HbA1c checked and acted on. Newly identified diabetes after a stroke is common |
| Patent foramen ovale closure | Considered in younger patients with an otherwise unexplained stroke and a suitable anatomy |
| Smoking, alcohol, weight, activity | Stopping smoking is the largest single behavioural change available. See alcohol and exercise |
| Atrial fibrillation screening, repeated | If nothing was found on the first monitor and the stroke remains unexplained, looking again later is reasonable |
9. What should be rechecked, and when
There is no single national schedule, and what follows is a reasonable default to hold a conversation against rather than a protocol.
| When | What |
|---|---|
| Weeks 1–6 | Blood pressure repeatedly as treatment is adjusted; medication tolerance and adherence; swallow and mood reassessed; rehabilitation under way |
| Around 3 months | A formal review — lipids on treatment, HbA1c, kidney function on any new drug, blood pressure against target, and a deliberate conversation about what has not recovered |
| 6 to 12 months | Lipids and blood pressure again, review of anticoagulation and bleeding risk if applicable, and driving and work questions |
| Annually thereafter | Blood pressure, lipids, HbA1c, kidney function, weight, atrial fibrillation check, and a medication review that asks whether each drug is still doing something |
| Any time | New neurological symptoms are an emergency again, not a follow-up question. A second stroke is treated on the same clock as the first |
Mood, fatigue and cognition are part of the follow-up, not an afterthought. Depression after stroke is common, under-recognised and treatable, and fatigue is one of the most disabling and least discussed consequences. Neither shows up on any of the tests above, and both should be asked about explicitly at every review.
10. What is coming
- Tenecteplase replacing alteplase as the default thrombolytic. A single bolus rather than an infusion, which shortens door-to-needle time and simplifies transfer.
- The late window. Whether thrombolysis beyond 4.5 hours helps, and in whom, is the most active question in the field — and the trials so far disagree, which is why this chapter presents them rather than a conclusion. The signal is strongest in people with a large vessel occlusion, salvageable tissue on perfusion imaging, and no access to thrombectomy.
- Imaging and triage. Automated perfusion analysis and pre-hospital scanning are widening who can be offered what, by identifying salvageable tissue faster.
- Novel antithrombotics aimed at reducing clot without the bleeding penalty are in trials. None has changed practice, and the pattern in this field is that most do not.
Currency warning. Sections 4 and 10 are the fastest-moving on this page and a single trial readout will date them. Reviewed August 2026.