What is the thrombolysis window in acute ischaemic stroke?

Within 4.5 hours of symptom onset, once intracranial haemorrhage has been excluded. NICE NG128 points to its technology appraisal guidance on tenecteplase, TA990 from 2024, and alteplase, TA264 from 2012, for treating acute ischaemic stroke in that window, and says the drug should only be given within a well-organised stroke service.

How late can thrombectomy be offered?

NICE NG128 offers thrombectomy within 6 hours of symptom onset for confirmed proximal anterior circulation occlusion, and offers it to people last known to be well between 6 and 24 hours previously, including wake-up strokes, where imaging such as CT perfusion or diffusion-weighted MRI shows the potential to salvage brain tissue. Posterior circulation occlusion is considered on the same 24-hour basis.

Who is selected for thrombectomy?

NICE NG128 asks you to take into account the person's overall clinical status and the extent of established infarction on initial imaging, and to select people with a pre-stroke functional status of less than 3 on the modified Rankin scale and a score of more than 5 on the National Institutes of Health Stroke Scale.

What dose of aspirin is given after an ischaemic stroke?

Aspirin 300 mg, as soon as possible and certainly within 24 hours of presentation once intracerebral haemorrhage has been excluded, given rectally or by enteral tube if the person has dysphagia. It continues at 300 mg daily until 2 weeks after onset, when definitive long-term antithrombotic treatment starts, or earlier if the person is discharged sooner.

When is blood pressure lowered in acute stroke?

In acute ischaemic stroke, NICE NG128 recommends antihypertensive treatment only for a hypertensive emergency such as encephalopathy, nephropathy, cardiac failure or myocardial infarction, aortic dissection or pre-eclampsia, and says a reduction to 185/110 mmHg or lower should be considered in thrombolysis candidates. In acute intracerebral haemorrhage, rapid lowering is considered within 6 hours when the systolic is 150 to 220 mmHg.

How soon is swallowing assessed after a stroke?

On admission, before the person is given any oral food, fluid or medication, screened by an appropriately trained healthcare professional. If the screen shows a problem, NICE NG128 asks for a specialist swallowing assessment, preferably within 24 hours of admission and no more than 72 hours afterwards.

Acute Stroke — IMT Interview Clinical Station Answer

Acute stroke at the IMT (Internal Medicine Training) clinical station is answered as a race against three clocks. NICE NG128 points to technology appraisal guidance for thrombolysis with alteplase or tenecteplase within 4.5 hours of symptom onset once haemorrhage is excluded, and recommends thrombectomy within 6 hours for proximal anterior circulation occlusion, extending to 24 hours where imaging shows brain worth saving.

Key takeaways

NICE NG128 asks for a validated tool such as FAST outside hospital and ROSIER in the emergency department, and says to exclude hypoglycaemia as the cause of sudden neurological symptoms.
Brain imaging is immediate, with a non-enhanced CT, if there are indications for thrombolysis or thrombectomy, anticoagulant treatment, a known bleeding tendency, a Glasgow Coma Score below 13, unexplained progressive or fluctuating symptoms, papilloedema, neck stiffness or fever, or severe headache at onset.
Thrombolysis is within 4.5 hours of symptom onset once intracranial haemorrhage has been excluded, using alteplase or tenecteplase as set out in NICE technology appraisal guidance.
Thrombectomy is offered within 6 hours with intravenous thrombolysis for confirmed proximal anterior circulation occlusion, and offered between 6 and 24 hours, including wake-up strokes, where imaging shows the potential to salvage brain tissue.
Aspirin 300 mg is given as soon as possible and certainly within 24 hours once haemorrhage is excluded, and continued daily at 300 mg until 2 weeks after onset.
Blood pressure is reduced to 185/110 mmHg or lower in people who are candidates for intravenous thrombolysis; otherwise antihypertensives in acute ischaemic stroke are reserved for a hypertensive emergency.

How do you recognise acute stroke in the scenario?

Acute stroke is recognised from a sudden focal neurological deficit, and NICE NG128 asks you to screen for it with a validated tool: FAST outside hospital, and ROSIER for people admitted to the emergency department.

The first thing to exclude is hypoglycaemia. NICE NG128 makes that a standalone recommendation, and saying it before you say CT shows the panel you think in stroke mimics.

The time of onset is the other half of recognition. If the deficit was present on waking, the onset time is when the patient was last known to be well, and in acute stroke that changes which windows are open.

What does the A to E assessment and the first hour look like?

The first hour of acute stroke is an A to E assessment, a capillary glucose, an immediate non-enhanced CT head, and a direct admission to a specialist acute stroke unit.

Airway and breathing: aspiration risk from a reduced conscious level, with oxygen given only if saturations drop below 95%, as NICE NG128 specifies
Circulation: blood pressure, rhythm for atrial fibrillation, intravenous access and bloods including full blood count, coagulation, urea and electrolytes
Disability: capillary glucose to exclude hypoglycaemia, conscious level, and a National Institutes of Health Stroke Scale score to quantify the deficit
Glucose control: NICE NG128 says to maintain a blood glucose concentration between 4 and 11 mmol per litre in people with acute stroke
Swallow: NICE NG128 says to screen swallowing on admission, by an appropriately trained professional, before giving any oral food, fluid or medication
Admission: admit everyone with suspected stroke directly to a specialist acute stroke unit after initial assessment

In practice the swallow screen is the mark candidates lose. Prescribing oral aspirin before swallowing has been screened is exactly the error the recommendation exists to prevent.

Which investigations does acute stroke need, and how fast?

The investigation that decides everything in acute stroke is the non-enhanced CT head, performed immediately where any of the NICE NG128 indications apply, and within 24 hours of symptom onset for everyone else.

Immediate non-enhanced CT if there are indications for thrombolysis or thrombectomy, the person is on an anticoagulant, has a known bleeding tendency, has a Glasgow Coma Score below 13, has unexplained progressive or fluctuating symptoms, has papilloedema, neck stiffness or fever, or had severe headache at onset
If thrombectomy might be indicated, follow the non-enhanced CT with CT contrast angiography, and add CT perfusion or the MR equivalent if thrombectomy might be indicated beyond 6 hours of symptom onset
Scan everyone else with suspected acute stroke as soon as possible and within 24 hours of symptom onset
For suspected transient ischaemic attack, NICE NG128 says not to offer CT brain scanning unless an alternative diagnosis is suspected that CT could detect, and to consider MRI after specialist assessment, performed the same day

What are the three time windows you have to know?

The three numbers that decide reperfusion in acute stroke are 4.5 hours, 6 hours and 24 hours, and they belong to different treatments. Say which is which.

Thrombolysis: NICE NG128 refers to technology appraisal guidance for tenecteplase and alteplase for treating acute ischaemic stroke within 4.5 hours of symptom onset, once intracranial haemorrhage has been excluded
Thrombectomy, anterior circulation: offer as soon as possible and within 6 hours of symptom onset, together with intravenous thrombolysis where that is not contraindicated and is within its licensed window, for confirmed proximal anterior circulation occlusion on CT or MR angiography
Thrombectomy, late window: offer as soon as possible to people last known to be well between 6 and 24 hours previously, including wake-up strokes, with a confirmed proximal anterior circulation occlusion and imaging showing the potential to salvage brain tissue
Thrombectomy, posterior circulation: consider up to 24 hours from last known well for confirmed basilar or posterior cerebral artery occlusion, again where imaging shows salvageable tissue

NICE NG128 adds a selection rule that candidates rarely quote. For thrombectomy, select people with a pre-stroke functional status of less than 3 on the modified Rankin scale and a score of more than 5 on the National Institutes of Health Stroke Scale.

It also says thrombolysis should be given only within a well-organised stroke service, with staff trained in delivering it and immediate access to imaging and re-imaging.

What is the definitive management of acute stroke?

Definitive management of acute ischaemic stroke is reperfusion where a window is open, aspirin for everyone else once haemorrhage is excluded, and a stroke unit with physiological control around both.

Aspirin 300 mg orally as soon as possible and certainly within 24 hours, or rectally or by enteral tube if there is dysphagia, continued daily at 300 mg until 2 weeks after onset, at which point long-term antithrombotic treatment starts
Offer a proton pump inhibitor alongside aspirin for anyone with previous aspirin-associated dyspepsia, and an alternative antiplatelet for genuine aspirin intolerance
NICE NG128 says not to use anticoagulation routinely for the treatment of acute stroke, and that people with disabling ischaemic stroke who are in atrial fibrillation should have aspirin 300 mg for the first 2 weeks before anticoagulation is considered
Do not start a statin in acute stroke, but continue one in people already taking it
For acute intracerebral haemorrhage, consider rapid blood pressure lowering within 6 hours of onset when the systolic is between 150 and 220 mmHg, aiming for a systolic of 140 mmHg or lower without a drop exceeding 60 mmHg in the first hour
Reverse warfarin in primary intracerebral haemorrhage with prothrombin complex concentrate and intravenous vitamin K

For transient ischaemic attack, NICE NG128 offers aspirin 300 mg daily immediately, specialist assessment within 24 hours of symptom onset, and says not to use scoring systems such as ABCD2 to decide urgency.

When and to whom do you escalate acute stroke?

Escalate acute stroke the moment the presentation is inside a reperfusion window, because the stroke physician and the radiologist have to be moving while you are still examining.

Call the thrombectomy centre for any confirmed proximal occlusion, and neurosurgery for a large intracerebral haemorrhage, hydrocephalus or a malignant middle cerebral artery syndrome that may need decompressive hemicraniectomy.

That said, the scenario often turns to premorbid function. The modified Rankin scale figure is a selection criterion, so gathering a collateral history about baseline function is a clinical task, not a formality.

How do you hand over acute stroke in one minute?

The acute stroke handover uses SBAR and leads with the time last known well, because that single fact decides which windows are still open.

Situation: a 68 year old last known well 95 minutes ago, with right-sided weakness and expressive dysphasia, NIHSS 14. Background: independent, modified Rankin 0, on no anticoagulant, blood pressure 176 over 92.

Assessment: acute ischaemic stroke inside the 4.5-hour window, capillary glucose 6.1, CT shows no haemorrhage, CT angiography shows a left middle cerebral artery occlusion. Recommendation: please attend now for thrombolysis and activate the thrombectomy pathway.

What does the panel listen for in an acute stroke answer?

The panel listens for the time last known well asked first, hypoglycaemia excluded, the 4.5-hour and 6-hour and 24-hour windows attached to the right treatments, and aspirin withheld until haemorrhage is excluded.

In practice they also mark the swallow screen, because it is the one recommendation that protects the patient in the next hour rather than the next week. The internalmedicineinterview bank of 361 questions across 56 scenarios, with AI-marked spoken practice, exists to make those sentences automatic under pressure.

What are the common mistakes in an acute stroke station?

Giving aspirin before the CT has excluded intracerebral haemorrhage
Giving oral medication before swallowing has been screened
Treating a wake-up stroke as out of time, when NICE NG128 offers thrombectomy up to 24 hours from last known well where imaging shows salvageable tissue
Lowering blood pressure in acute ischaemic stroke when the patient is not a thrombolysis candidate and has no hypertensive emergency
Using ABCD2 to decide how urgently to see a transient ischaemic attack, which NICE NG128 says not to do
Forgetting hypoglycaemia, which is both the commonest stroke mimic and a named NICE recommendation

How this comes up at the IMT interview

Acute stroke maps onto all three parts of the IMT clinical station. Investigations and diagnosis is the glucose, the non-enhanced CT and the angiography decision; management is the reperfusion window, aspirin, glucose control and the stroke unit; and communication is explaining thrombolysis risk to a family in minutes rather than hours.

The handover minute is where the time last known well, the NIHSS and the imaging finding have to be said in order, with an explicit request that names the treatment you want.

Acute Stroke and Thrombolysis Windows: 4.5 Hours, 6 Hours and 24 Hours