3.2 Ischaemic stroke – Cerebral artery thrombosis

📄 Definition

  • Ischaemic Stroke: Focal brain infarction with symptoms lasting >24 hours.

  • TIA: Neurological deficit resolving within 24 hours. (Note: Most TIAs actually resolve within 1 hour).

🧠 Transient Ischaemic Attack (TIA): Neurological symptoms resolve within <24 hours and no infarction seen on imaging.

🧠 Causes – Mnemonic: THROMBO

  • Thromboembolism (from carotids or heart, e.g. AF)

  • Hypertension

  • Risk factors: smoking, diabetes, hyperlipidaemia

  • Oral contraceptives (young women)

  • Mural thrombus post-MI

  • Blood disorders (e.g. polycythaemia)

  • Other: carotid dissection, vasculitis

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🎯 EXAM ANCHOR – ANATOMY TRAPS

  • MCA (Middle Cerebral): Most common. Affects the Face and Arm more than the Leg. Includes Aphasia (if dominant hemisphere).

  • ACA (Anterior Cerebral): Rare. Affects the Leg more than the Arm.

  • POCI (Posterior): Think Ataxia and Cranial Nerve palsies. If they mention “Crossed signs” (Face one side, body the other), it’s always a Brainstem/Posterior stroke.

🎯 EXAM ANCHOR – IDENTIFYING THE SOURCE (THROMBO)

The PARA exam will often give you a cause from your THROMBO list and ask for the “Next Investigation” to prove it.

    • AF (Thromboembolism): If the pulse is irregular, the next step is an ECG or 24-hour Holter.

    • Carotids (Thromboembolism): If a carotid bruit is heard, the next step is Carotid Doppler Ultrasound.

    • Mural Thrombus (Post-MI): If the patient has a history of a large anterior MI, the next step is an Echocardiogram.

    • Oral Contraceptives: If the patient is a young female smoker on the pill, they are at high risk for both arterial stroke and Cerebral Venous Sinus Thrombosis (CVST).

⚠️ Symptoms – FAST + others

  • Face drooping

  • Arm weakness

  • Speech disturbance

  • Time (act quickly)

  • Visual loss (amaurosis fugax, homonymous hemianopia)

  • Ataxia, vertigo (posterior circulation)

  • Dysphagia

  • Confusion or altered mental status

🎯 EXAM ANCHOR – THE STROKE “MIMIC”

Before CT or any intervention, you must perform a Capillary Blood Glucose.

📌 PARA commonly asks:

Hypoglycaemia can present with focal neurological deficits (hemiparesis/slurred speech) and is the most common stroke mimic.

 

🥇 First-Line (Immediate)

  • ABCDE assessment

  • Blood glucose – rule out hypoglycaemia mimic

  • Urgent CT Head (within 1 hour) – exclude haemorrhage

  • ECG – AF or MI

  • FBC, U&Es, LFTs, Clotting, CRP, Lipids, HbA1c

🎯 THE ACUTE EMERGENCY

  • Safety First: Capillary Blood Glucose (Rule out hypoglycemia).

  • Imaging: Non-contrast CT Head within 1 hour.

Treatment Windows:

  • Alteplase: <4.5 hours.

  • Thrombectomy: <6 hours (Large Vessel Occlusion).

  • Aspirin 300mg: Immediately after CT (unless thrombolysed, then wait 24h).

🧪 Investigations 

🥈 Second-Line

  • CT Angiography (CTA) – assess large vessel occlusion

  • Carotid Doppler US – check for stenosis

  • MRI Brain – more sensitive for posterior strokes

🎯 EXAM ANCHOR – SECONDARY PREVENTION TITRATION

  1. Immediate: Give Aspirin 300 mg stat (unless anticoagulated or bleeding disorder).

  2. Referral: All TIAs must be seen by a specialist within 24 hours.

  3. Driving: Advise the patient not to drive until cleared by a specialist.

📌 PARA commonly asks:

A patient had a 10-minute episode of slurred speech 4 hours ago. They are now back to normal. What is the next step?” 

 

🥉 Tertiary

  • Echocardiogram – embolic source

  • 24h Holter – paroxysmal AF

  • Thrombophilia screen – if <50 or unexplained stroke

Management – Mnemonic: ACT FAST

  • Antiplatelet – 300 mg aspirin STAT after haemorrhage excluded

  • CT Head – done urgently

  • Thrombolysis – alteplase IV within 4.5 hrs (if criteria met)

  • Fibrinolysis contraindicated? → consider thrombectomy (within 6 hours)

  • Antihypertensives – only if BP >185/110 mmHg

  • Statin – atorvastatin 80 mg after 48 hrs

  • TIA: refer to stroke clinic within 24 hours

🎯 EXAM ANCHOR – ACUTE MANAGEMENT WINDOWS

Management is dictated entirely by the time from symptom onset.

  • CT Head: Perform immediately (ideally within 1 hour) to exclude intracranial haemorrhage.

  • Thrombolysis (Alteplase): Administer within 4.5 hours.

  • Thrombectomy: Offer within 6 hours for confirmed large vessel occlusion (LVO). Can be considered up to 24 hours if there is salvageable brain tissue on advanced imaging.

  • Aspirin 300 mg: Give only after haemorrhage is excluded on CT.

    • Note: If thrombolysis is given, delay Aspirin for 24 hours.

Secondary Prevention (LONG-TERM)

  • 1st Line: Clopidogrel 75mg + Atorvastatin 80mg.

  • AF-Stroke: Start DOAC after 14 days.

  • Carotid Stenosis (>50%): Refer for Endarterectomy within 14 days.

  • Driving: 1 month ban for both Stroke and TIA.

Complications – Mnemonic: BE FAST

  • Brain oedema

  • Embolism recurrence

  • Falls

  • Aspiration pneumonia

  • Seizures

  • TIA or progression to haemorrhagic stroke

🎯 EXAM ANCHOR – THE “SAFETY CHECKS”

The PARA will often present a patient who could have thrombolysis but has a hidden contraindication. 

You must NOT thrombolyse if:

  • Blood Pressure: >185/110 mmHg (Must lower safely before starting).

  • Glucose <2.8 or >22.2 mmol/L.

  • Surgery/Trauma within last 21 days.

  • Anticoagulated (INR >1.7 or on DOAC).

The “Permissive Hypertension” Rule

This is the most common trap in PARA finals.

  • The Rule: In a standard ischemic stroke, we do not lower the blood pressure (BP) acutely unless it is dangerously high (typically >220/120 mmHg).

  • The Reason: The brain tissue surrounding the dead zone (called the Penumbra) is struggling for life. Lowering the BP too quickly reduces “perfusion pressure,” which can turn salvageable brain tissue into a permanent infarct (dead tissue).

🔎 Key PARA Exam Traps

💡 The “Next Step” post-CT: If the CT shows no blood and the patient is within 4.5 hours, the next step is Thrombolysis, not Aspirin.

💡 Posterior Circulation: If the symptoms are vertigo, ataxia, or “locked-in” syndrome, the lesion is in the Basilar Artery/Posterior circulation. CT is often normal; MRI is the investigation of choice here.

💡 Carotid Endarterectomy: Offered if there is >50% stenosis (symptomatic) and the patient is fit for surgery. This should be done within 14 days of the stroke/TIA.

💡 AF Source: If the stroke was caused by AF, do not use Clopidogrel. Use a DOAC (started 14 days after the stroke).

🔒 Last updated in line with:

  • NICE NG128 (Stroke and TIA: 2019, updated 2022/23).

  • Last reviewed: February 2026.

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Educational platform. Not medical advice.

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