Overview
This lecture covers the major stroke syndromes, focusing on their vascular territories, clinical features, and key neuroanatomy relevant to diagnosis.
Middle Cerebral Artery (MCA) Syndrome
- MCA supplies the lateral frontal, parietal, and part of the temporal lobe.
- Contralateral hemiplegia and sensory loss: face and upper extremities > lower extremities.
- Superior division infarct: affects motor and sensory cortices, frontal eye fields (causing gaze deviation to lesion side), and Broca’s area (expressive aphasia).
- Inferior division infarct: affects Wernicke’s area (receptive aphasia), and optic radiations (contralateral homonymous hemianopia).
- Right (non-dominant) MCA: leads to hemineglect and apraxia.
Anterior Cerebral Artery (ACA) Syndrome
- ACA supplies the medial frontal and parietal lobes.
- Contralateral hemiplegia and sensory loss: lower extremities > upper extremities/face.
- Damage to paracentral lobule: urinary and fecal incontinence.
- Involvement of prefrontal cortex and cingulate: abulia (lack of motivation) or akinetic mutism.
- Lesion near Broca’s area: transcortical motor aphasia (can repeat words, non-fluent speech).
Watershed Infarcts
- ACA-MCA watershed: "man in a barrel" syndrome (proximal upper and lower extremity weakness/sensory loss).
- MCA-PCA watershed: visual association deficits (e.g., prosopagnosia, Balint's syndrome).
Internal Carotid Artery (ICA) Syndrome
- ICA supplies both MCA and ACA territories, may cause combined symptoms.
- Can cause transient monocular vision loss (amaurosis fugax) via ophthalmic artery involvement.
Posterior Cerebral Artery (PCA) Syndrome
- PCA supplies occipital lobe, thalamus, and midbrain.
- Contralateral homonymous hemianopia (visual cortex involvement).
- Midbrain syndromes:
- Weber: ipsilateral oculomotor palsy, contralateral hemiplegia.
- Claude: ipsilateral oculomotor palsy, contralateral ataxia.
- Benedict: features of both Weber and Claude.
Basilar Artery Syndromes
- Basilar artery supplies pons and cerebellum.
- Medial pons: contralateral hemiplegia/sensory loss, ipsilateral abducens palsy.
- Lateral pons (AICA): ipsilateral ataxia, facial weakness, hearing loss, Horner's syndrome, vertigo, nystagmus.
- Cerebellar involvement: ataxia, dysmetria, and dysdiadochokinesia.
Vertebral Artery & Posterior Inferior Cerebellar Artery (PICA) Syndromes
- Vertebral/anterior spinal artery: medial medulla—contralateral hemiplegia, sensory loss, ipsilateral tongue weakness.
- PICA: lateral medulla (Wallenberg syndrome)—ipsilateral ataxia, Horner’s, facial sensory loss, contralateral body sensory loss, dysphagia, dysphonia, vertigo, nystagmus.
Key Terms & Definitions
- Hemiplegia — paralysis of one side of the body.
- Homonymous hemianopia — loss of the same visual field in both eyes.
- Aphasia — impairment of language (Broca's: expressive, Wernicke's: receptive).
- Hemineglect — lack of awareness of one side of space.
- Abulia — lack of will or initiative.
- Akinetic mutism — absence of movement or speech.
- Ataxia — lack of coordination.
- Wallenberg syndrome — lateral medullary syndrome due to PICA infarct.
- Watershed zone — area between two vascular territories prone to ischemia.
- Amaurosis fugax — transient monocular vision loss.
Action Items / Next Steps
- Review vascular territories of cerebral arteries.
- Practice neuroanatomy localization.
- Memorize hallmark symptoms for each stroke syndrome.
- Complete assigned readings on cerebrovascular stroke syndromes.