Capsular (and Pontine) Warning Syndromes

Learning objectives

Introduction

• Capsular warning syndrome first described by Donnan in 1993
• Repeated sensory and/or motor symptoms affecting at least two of the face, arm and leg, without cortical signs
• Recurrent stereotyped lacunar TIAs with increased risk of developing stroke
• Can also happen with pontine strokes

Aetiology

• Exact aetiology of the syndrome not clear
• Presumed angiopathy of a lenticulostriate artery.
• Ischaemia within the internal capsule
• Might be large vessel syndrome restricting flow to perforator vessels
• Possibly seen with pontine perforators too (pontine warning syndrome)
• crescendo episodes of ischaemia restricted to the region of the internal capsule
• Usually causing symptoms affecting face, arm, and leg.
• Small vessel disease associated with hypertension, diabetes mellitus, and dyslipidemia

Clinical

• Repeated sensory and/or motor symptoms affecting at least two of the face, arm and leg, without cortical signs
• Pontine warning syndrome : gaze palsies, dysarthria and ataxic hemiparesis

Investigations

• FBC, U&E, LFTs, Glucose, lipids
• CT/CTA as needed
• Carotid doppler if anterior circulation
• MRI may show a lacunar infarct in the internal capsule or the corona radiata. With a pontine warning syndrome evidence of infarction involving pontine corticospinal and sensory tracts may be seen
• Consider MRA to look for vascular stenosis
• EEG if seizure suspected

Differentials of repeated stereotypical negative neurology

• Severe Carotid stenosis
• Artery to artery embolisation
• Migraine
• Seizures

Management

• Reperfusion therapies where indicated - reperfusion of an MCA may increase flow to the lenticulostriate artery.
• Admission to stroke unit
• Aspirin 300 mg +/- Clopidogrel
• Optimise BP control if hypertension and glucose control if diabetic
• Statin to lower Cholesterol

References

• Donnan GA, O'Malley HM, Quang L, Hurley S, Bladin PF: The capsular warning syndrome: pathogenesis and clinical features. Neurology 1993;43:957-962.
• Huang HW, He SW, Tan SQ, Su LL: Patient with pontine warning syndrome and bilateral posterior internuclear ophthalmoplegia: case report. BMC Neurol 2010;10:55.
• Saposnik G, Noel de Tilly L, Caplan LR. Pontine Warning Syndrome. Arch Neurol. 2008;65(10):1375–1377. doi:10.1001/archneur.65.10.1375