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Section 9 — Neurology Verify against local policy v1.0 · July 2026

Chapter 9.5 — Perinatal Arterial Ischemic Stroke

Focal seizures in a well-looking term baby: recognition, MRI/MR-angiography diagnosis, supportive (usually non-anticoagulant) management, and follow-up — built on West Midlands Neonatal Guidelines 2025–28 and RCPCH/AHA neonatal stroke guidance

Educational guideline — verify locally. Neonatal arterial ischemic stroke is usually managed supportively; anticoagulation/antiplatelet therapy is reserved for specific indications (e.g., cardioembolic source) on specialist advice. Verify against local/neurology policy. Does not replace attending judgment.
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1. Overview

Overview

Perinatal arterial ischemic stroke is a focal infarction of the brain due to arterial occlusion around the time of birth, most commonly in the middle cerebral artery territory. It classically presents as focal seizures in an otherwise well term infant and is a leading cause of hemiplegic cerebral palsy. Diagnosis rests on MRI; management is largely supportive because most neonatal strokes are not amenable to acute reperfusion or routine anticoagulation, though the cause should be sought and specialist input obtained.

Why This Topic Matters

PAIS is often missed because the baby looks well between seizures and cranial ultrasound can be normal. Recognizing the pattern, obtaining MRI, and arranging follow-up (for hemiplegia and epilepsy) enables early intervention and appropriate counseling.

2. Who This Guideline Applies To

Scope
  • Term (and near-term) infants with focal seizures or focal neurological signs, and infants with suspected/confirmed stroke.
  • Includes arterial ischemic stroke; cerebral sinovenous thrombosis and hemorrhagic stroke are related and need specialist input.
  • Cross-references: seizures (9.3), HIE (9.1), thrombosis (10.9), and congenital heart disease (3.3).

3. Key Definitions

TermDefinition
PAISPerinatal arterial ischemic stroke — focal arterial infarction around birth.
CSVTCerebral sinovenous thrombosis — venous stroke; may need anticoagulation (specialist).
DWIDiffusion-weighted MRI — detects acute infarction earliest.
Hemiplegic CPOne-sided cerebral palsy — the commonest motor outcome of PAIS.

4. Presentation

Focal Seizures in a Well Baby
  • Focal (often unilateral clonic) seizures in the first days of life, typically in a well-appearing term infant between events.
  • May also present later with early hand preference/asymmetry of movement (retrospective diagnosis), or with encephalopathy if extensive.
  • Unlike HIE, the infant is often not globally encephalopathic — the seizure is the clue.

5. Risk Factors

Contributors (Often Multifactorial)
  • Maternal/pregnancy: pre-eclampsia, chorioamnionitis/infection, prothrombotic states, difficult delivery.
  • Fetal/neonatal: congenital heart disease (cardioembolic), infection/sepsis, dehydration, polycythemia, thrombophilia (selected).
  • Often multiple interacting factors; a specific cause is not always found.

6. Imaging & Work-up

MRI Is Key
  • MRI with DWI (± MR angiography/venography) is the diagnostic test — it detects acute infarction and territory; cranial ultrasound frequently misses acute stroke.
  • EEG/aEEG to confirm and monitor seizures (see 9.3).
  • Investigate contributing factors per specialist advice: infection screen; consider echocardiography (cardioembolic source) and, in selected cases, thrombophilia testing.

7. Management Algorithm

1
Focal seizures in a term baby
Suspect stroke; treat seizures (see 9.3) and investigate the cause — don't stop at "seizures."
2
MRI with DWI
Confirm and localize infarction (± MRA/MRV); ultrasound often misses it; EEG/aEEG for seizures.
3
Supportive care
Control seizures; maintain normal glucose, electrolytes, temperature, oxygenation, and perfusion; treat infection.
4
Seek the cause
Consider cardioembolic source (echo), infection, and selected thrombophilia testing per specialist advice.
5
Anticoagulation only if indicated
Not routine for PAIS; reserved for specific indications (e.g., cardioembolic source, CSVT) on neurology/hematology advice.
6
⚠ Do-not-miss
Relying on normal ultrasound; missing cardioembolic source/CSVT; and failing to arrange neurodevelopmental follow-up.

8. Management

Mostly Supportive
  • Control seizures per the neonatal seizures pathway (see 9.3); treat only ongoing/electrographic seizures and wean anticonvulsants appropriately.
  • Maintain normal physiology (glucose, electrolytes, temperature, oxygenation, blood pressure/perfusion); treat any infection.
  • Anticoagulation/antiplatelet therapy is not routine for arterial ischemic stroke — reserve for specific indications (e.g., cardioembolic source, cerebral sinovenous thrombosis) on specialist advice.
  • Involve pediatric neurology; arrange early neurodevelopmental follow-up and intervention.

9. Outcome & Follow-up

Variable — Follow-up Matters
  • Outcomes vary with infarct size/location; the commonest sequela is hemiplegic cerebral palsy; risks also include epilepsy, cognitive and language difficulties, and visual field defects.
  • Many infants do well — counsel honestly and avoid over-pessimism.
  • Arrange structured neurodevelopmental follow-up, early therapy (physiotherapy/occupational therapy), and monitoring for epilepsy; support the family.

10. Monitoring

ParameterWhenAction
Seizures (EEG/aEEG)Acute phaseConfirm/treat; wean anticonvulsants (see 9.3).
Physiology (glucose/electrolytes/BP)ContinuousMaintain normal; treat infection.
MRIAt diagnosisConfirm/localize; guide prognosis.
Cause work-upPer specialistEcho/thrombophilia in selected cases.
NeurodevelopmentStructured follow-upDetect hemiplegia/epilepsy; intervene early.

11. Precautions

Safety Cautions
  • Do not rely on a normal cranial ultrasound to exclude stroke — obtain MRI with DWI.
  • Do not stop at "seizures" — investigate the underlying cause.
  • Anticoagulation is not routine for arterial ischemic stroke — use only for specific indications on specialist advice.
  • Consider a cardioembolic source (echo) and CSVT.
  • Arrange neurology and neurodevelopmental follow-up; counsel without over-pessimism.

12. Escalation & Family Support

Family-Centered Communication
  • "Your baby has had a stroke — a blockage affecting one area of the brain — which showed up as seizures. A special scan (MRI) confirms it."
  • "We control the seizures and support your baby; blood-thinning medicine isn't usually needed. Many babies do well, and we'll arrange follow-up and therapy to give the best outcome."

13. Key Pearls

High-Value Clinical Pearls
  • Focal seizures in a well term baby = suspect perinatal arterial ischemic stroke (2nd commonest cause of neonatal seizures after HIE).
  • MRI with DWI diagnoses it; cranial ultrasound often misses acute infarction.
  • Management is mostly supportive (seizure control, normal physiology); anticoagulation is not routine.
  • Consider a cardioembolic source (echo) and CSVT; investigate the cause.
  • Commonest sequela is hemiplegic cerebral palsy; also epilepsy/cognitive/visual risks — but many do well.
  • Arrange neurology and neurodevelopmental follow-up with early intervention.

14. Common Mistakes to Avoid

MistakeWhy it harmsBetter practice
Excluding stroke on ultrasound.Misses infarction.Obtain MRI with DWI.
Stopping at "seizures."Misses the cause.Investigate; consider stroke.
Routine anticoagulation.Bleeding risk, no benefit.Reserve for specific indications.
Ignoring cardiac source/CSVT.Missed embolic/venous cause.Echo; consider CSVT.
No follow-up.Missed hemiplegia/epilepsy.Neurodevelopmental follow-up.

15. Board-Style High-Yield Summary

Key Takeaways
  • PAIS = focal arterial infarction (often MCA) presenting as focal seizures in a well term infant; 2nd commonest cause of neonatal seizures after HIE.
  • Diagnose with MRI + DWI (± MRA/MRV); cranial ultrasound often misses it.
  • Management is mostly supportive (seizure control, normal physiology, treat infection).
  • Anticoagulation is not routine — reserve for cardioembolic source/CSVT on specialist advice.
  • Investigate the cause; consider echocardiography and (selected) thrombophilia testing.
  • Commonest outcome is hemiplegic cerebral palsy (also epilepsy/cognitive/visual risks); arrange follow-up and early intervention.

16. References

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