Neurology

Ischemic Stroke

Q: Current TIA definition?

Transient neurologic dysfunction from focal ischemia without acute infarction on imaging.

Q: Thrombectomy window?

Up to 24 h with favourable core/penumbra mismatch (DAWN, DEFUSE-3).

Q: BP goal during alteplase?

<185/110 pre and <180/105 for 24 h after.

Acute focal neurologic deficit from arterial occlusion causing brain infarction; time-sensitive reperfusion saves brain tissue: 'time is brain'.

Last reviewed 30 Jun 2026 - MedicoMedics editorial team

Cerebral ischemia with core and penumbra

Pathophysiology

Large-artery atherosclerosis, cardioembolism (AFib), small-vessel lacunar, other (dissection, hypercoagulable). Salvageable penumbra surrounds irreversible core.

Sources: AHA/ASA Stroke (Stroke 2019;50:e344); DAWN (NEJM 2018;378:11)

Presentation

Sudden hemiparesis, hemisensory loss, aphasia (dominant), neglect (non-dominant), gaze deviation, facial droop. NIHSS quantifies severity.

Diagnosis

Non-contrast CT excludes haemorrhage; CTA identifies large-vessel occlusion; CT perfusion or MRI-DWI defines core/penumbra for extended-window thrombectomy.

Management

IV alteplase or tenecteplase within 4.5 h (up to 9 h with mismatch). Thrombectomy for LVO up to 24 h. BP <185/110 pre-lytic. Secondary prevention: antiplatelet or DOAC for AFib, statin.

Sample USMLE-style MCQs

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Question 1

68-year-old 90 min after right hemiplegia and aphasia. NIHSS 14. Non-contrast CT excludes bleed. Next?

Question 2

A patient presents 2 h after left hemiparesis onset. CT: no bleed. What next?

Question 3

Absolute contraindication to alteplase?

Question 4

MCA M1 occlusion at 8 h with penumbra on CTP. Best therapy?

Question 5

AFib with prior TIA, CHA2DS2-VASc 4. Best long-term prevention?

Question 6

Long-term stroke prevention in AF?

Question 7

Which BP threshold contraindicates thrombolysis?

Question 8

Pure motor hemiparesis localises to?

Question 9

LVO at 8 h with small core and large penumbra. Best therapy?

Question 10

Which trial extended thrombectomy to 24 h?

References

Primary guidelines and peer-reviewed sources used for this entry. Reviewed 30 Jun 2026 by MedicoMedics editorial team.

Frequently asked

Current TIA definition?

Transient neurologic dysfunction from focal ischemia without acute infarction on imaging.

Thrombectomy window?

Up to 24 h with favourable core/penumbra mismatch (DAWN, DEFUSE-3).

BP goal during alteplase?

<185/110 pre and <180/105 for 24 h after.

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