Makindo Medical Notes

Related Subjects: |Hypertension |Causes of Stroke |Ischaemic Stroke |Acute Stroke Assessment (ROSIER&NIHSS) |Atrial Fibrillation |Atrial Myxoma |Causes of Stroke |Cancer and Stroke

⚠️ Capsular Warning Syndrome (CWS) is an important stroke emergency. It describes recurrent, stereotyped motor and/or sensory attacks affecting face, arm, and leg (at least two areas), without cortical signs. It carries a very high short-term risk of completed stroke, making early recognition and treatment essential.

📖 Introduction

• First described by Donnan in 1993.
• Characterized by repeated stereotyped lacunar TIAs, often over hours to days.
• Symptoms affect ≥2 of face, arm, and leg, but no cortical features (e.g., no dysphasia, neglect, or visual field defects).
• When similar recurrent symptoms involve the pons → termed Pontine Warning Syndrome.
• 🧠 Clinical importance: Up to 40–60% risk of progression to completed stroke within 7 days.

🩺 Aetiology & Pathophysiology

• Exact mechanism unclear, but thought to involve:
  • Occlusion/angiopathy of a lenticulostriate perforator artery.
  • Restricted blood flow due to lipohyalinosis in small vessel disease (associated with HTN, DM, dyslipidaemia).
  • Large vessel disease affecting perforator origins (e.g., MCA plaque encroachment).
  • Crescendo ischaemia → repeated brief deficits, progressing to permanent infarct.
• Pontine warning syndrome involves basilar perforators, often with gaze palsy, dysarthria, and ataxia.

🧑‍⚕️ Clinical Presentation

• Recurrent stereotyped episodes of:
  • Motor weakness
  • Or sensory loss
  • Or mixed motor-sensory deficits
  affecting ≥2 of face, arm, and leg.
• Episodes last minutes to hours, recur over 24–72h, and often resolve completely between attacks.
• Pontine syndrome: May include dysarthria, gaze palsies, or ataxic hemiparesis.
• No cortical features (aphasia, neglect, hemianopia).

🔍 Investigations

• Bloods: FBC, U&E, LFTs, glucose, lipids (risk factor profiling).
• CT/CTA: Exclude haemorrhage, assess for large-vessel stenosis.
• MRI/MRA: Lacunar infarcts in internal capsule or corona radiata; high sensitivity for small vessel disease.
• Carotid Doppler: If anterior circulation suspected.
• EEG: Only if seizure mimic suspected.

🧾 Differential Diagnoses

• Severe carotid stenosis
• Artery-to-artery embolism
• Migraine aura
• Focal seizures

💊 Management

• Stroke unit admission for monitoring due to high early stroke risk.
• Reperfusion therapies: Thrombolysis/thrombectomy may be used if patient presents within the therapeutic window.
• Dual antiplatelet therapy (DAPT): Aspirin 300 mg + Clopidogrel 300 mg (loading), then short-term dual therapy as per local protocol (e.g. 21 days per CHANCE/POINT trials).
• Risk factor control: Tight blood pressure control, glucose management, lipid-lowering with statins.
• Close neurological monitoring: Escalation if crescendo symptoms continue.

📚 References

• Donnan GA et al. The Capsular Warning Syndrome: Neurology 1993;43:957-962
• Saposnik G, Caplan LR. Pontine Warning Syndrome. Arch Neurol. 2008;65(10):1375–7
• Huang HW et al. Pontine Warning Syndrome: Case Report. BMC Neurol 2010;10:55

💡 Teaching Pearl: CWS is the “crescendo angina of stroke neurology.” Multiple stereotyped lacunar TIAs in a short time-frame demand urgent admission, dual antiplatelets, and risk-factor optimisation.