Stroke

Ischaemic stroke (80% of cases) - It's most commonly due to thrombus formation in large vessel atherosclerosis e.g. carotid, and subsequent embolus. It can also be due to a cardio-embolism e.g. in AF, or multiple intracranial small vessel atherosclerosis

Haemorrhagic stroke (20%) - Due to bleeding within brain parenchyma or ventricular system (Intracerebral) or into arachnoid space (Subarachnoid)

Risk Factors

• CVD e.g. Angina, MI, PVD

• Atherosclerosis

• AF

• Previous TIA/Stroke

• HTN, DM. Smoking

• COCP, Thrombophilia

Stroke Classification

Total Anterior Circulation Infarct (TACI) - This involves both the anterior and middle cerebral arteries, and presents with a triad of:

• Contralateral hemiparesis (weakness) or hemiplegia (paralysis) AND

• Contralateral homonymous hemianopia AND

• Higher cerebral dysfunction (e.g. aphasia, neglect)

Partial Anterior Circulation Infarct (PACI) - This involves either the anterior or middle cerebral artery, and presents with either:

• 2/3 of that in a TACI OR

• Higher cerebral dysfunction alone

Posterior Circulation Infarct (POCI) - Involves the posterior cerebral artery, and can present with:

• Cerebellar dysfunction OR

• Conjugate eye movement disorder OR

• Bilateral motor/sensory deficit OR

• Ipsilateral cranial nerve palsy with contralateral motor/sensory deficit OR

• Cortical blindness/isolated hemianopia

• Vestibular dysfunction, tested for with HINTS Plus

N.B. A POCI can present very similarly to peripheral vestibular dysfunction, therefore has to be differentiated with a HINTS Plus test.

Lacunar infarcts present with pure motor, pure sensory, sensorimotor stroke, or ataxic hemiparesis. But, they won't present with visual field defect, higher cerebral dysfunction, or brainstem dysfunction.

Posterior Stroke Syndromes

• Medial Midbrain Syndrome (Weber’s Syndrome) - Presents with:

  • Ipsilateral CN 3 palsy (complete ptosis)

  • Contralateral hemiparesis

• Lateral Pontine Syndrome due to an occlusion of the Anterior Inferior Cerebellar Artery (AICA) - Presents:

  • Similar to Wallenberg’s, but + involvement of CN 5-8 (e.g. vertigo, nausea)

• Lateral Medullary Syndrome (Wallenberg’s Syndrome) due to an occlusion of the Posterior Inferior Cerebellar Artery (PICA) - Presents with:

  • Ipsilateral Horner’s syndrome (partial ptosis)

  • Ipsilateral facial loss of pain and temperature sensation

  • Contralateral loss of pain and temperature sensation of the body

• Basilar Artery Occlusion - Presents with:

  • Locked-in syndrome (quadraperesis with preserved consciousness and ocular movements), loss of consciousness, or sudden death.

N.B. Remember the origin of the cranial nerves by the “rule of 4”. Midbrain = CN 1-4. Pons = CN 5-8. Medulla = CN 9-12.

Management

• CT Head (within 1 hr) to exclude haemorrhage

  • Once excluded, if < 4.5 hours - Thrombolysis with Alteplase (tPA)

  • Thrombectomy if within 6-12 hrs

• NBM until swallowing assessment done

• Immediate Aspirin 300mg for 14 days

  • Switch to Clopidogrel 75mg OD for long-term prevention

• Atorvastatin 20-80mg

Other things to do include:

• Manage modifiable risk factors, like HTN, DM, Smoking

• Consider carotid endarterectomy/stenting if severe carotid artery disease (>50% and symptomatic)