Lecture Notes: Stroke Syndromes

Introduction

• Importance of understanding stroke syndromes:
  • Patient presentation varies based on affected vascular territory.
  • Knowing which vessel supplies specific brain areas helps predict clinical manifestations.

MCA Syndrome (Middle Cerebral Artery Syndrome)

Vascular Supply

• Supplies:
  • Frontal lobe (lateral side),
  • Parietal lobe (lateral side),
  • Temporal lobe (part).
• Diagram indicating MCA territory in green.

Clinical Manifestations

• Motor Cortex Damage:

  • Weakness on the contralateral side (e.g., right MCA affects left side).
  • Motor Homunculus:
    • Lateral portion = face and upper extremities.
    • Medial portion = lower extremities.
  • Result: Contralateral hemiparesis (weakness) more in face and upper extremity than lower extremity.

• Sensory Cortex Damage:

  • Loss of sensation on the contralateral side.
  • Similar homunculus representation.
  • Result: Contralateral sensory loss, again more in face and upper extremity.

• Frontal Eye Fields Damage:

  • Located anterior to the motor cortex.
  • Damage results in ipsilateral gaze deviation (eyes deviate towards affected side).

• Wernicke's Area Damage:

  • Located in inferior division of the MCA.
  • Leads to Wernicke's aphasia (inability to comprehend language).

• Broca's Area Damage:

  • Located in superior division of the MCA.
  • Leads to Broca's aphasia (inability to express language).

MCA Divisions

• Superior Division:
  • Supplies primary motor cortex and somatosensory cortex.
• Inferior Division:
  • Supplies Wernicke's area.

Visual Processing

• Optic Radiations:
  • Damage in inferior division can lead to contralateral homonymous hemianopia.

Right MCA Damage Effects

• Apraxia and hemi-neglect can occur due to damage in the non-dominant hemisphere.

ACA Syndrome (Anterior Cerebral Artery Syndrome)

Vascular Supply

• Primarily supplies medial frontal and parietal lobes.

Clinical Manifestations

• Contralateral weakness and sensory loss (more in lower extremities).
• Urinary and fecal incontinence if the paracentral lobule is affected.
• Behavioral changes, such as abulia (lack of will) or akinetic mutism with bilateral damage.
• Potential transcortical motor aphasia if specific connections to Broca's area are affected.

Watershed Zones

• MCA-ACA watershed zone: susceptible to ischemia leading to proximal upper and lower extremity weakness and sensory loss (man-in-a-barrel syndrome).
• MCA-PCA watershed zone: can lead to visual dysfunction (prosopagnosia and balance syndrome).

ICA Syndrome (Internal Carotid Artery Syndrome)

• Occlusion can impact blood flow to both MCA and ACA territories.
• Symptoms may overlap with those of MCA and ACA syndromes.
• Can cause transient monocular vision loss (amaurosis fugax) if the ophthalmic artery is affected.

PCA Syndrome (Posterior Cerebral Artery Syndrome)

Vascular Supply

• Supplies occipital lobe, part of the thalamus, and midbrain.

Clinical Manifestations

• Contralateral homonymous hemianopia if the visual cortex is affected.
• Midbrain lesions can lead to syndromes such as Weber's, Claude's, and Benedict's syndromes.

Basilar Artery Syndrome

• Supplies the pons and cerebellum.
• Symptoms include:
  • Ipsilateral sixth nerve palsy (abducens).
  • Contralateral hemiplegia (if corticospinal tract is affected).
  • Ataxia (if cerebellar structures are involved).

Vertebral Artery Syndromes

• Supplies the medulla and posterior inferior cerebellum.
• Medial Medulla Damage:
  • Results in ipsilateral tongue deviation and contralateral hemiplegia.
• Lateral Medulla Damage (Wallenberg Syndrome):
  • Affects swallowing, speech (bulbar palsy), and causes vertigo/nausea due to vestibular nuclei involvement.

Conclusion

• Stroke syndromes are complex and depend on the vascular territory affected.
• Understanding these syndromes aids in diagnosis and management.