The Stroke Patient
Week 9: Nervous System | Difficulty: Advanced | Time: 45 minutes
Learning Objectives
- Apply neuroanatomical knowledge to localize stroke lesions
- Explain cerebral blood supply and consequences of interruption
- Understand the ischemic cascade and neuronal injury
- Connect functional brain areas to clinical deficits
- Describe neural pathways and their clinical relevance
Case Presentation
Patient: Margaret Wilson, 71-year-old female
History: Hypertension, atrial fibrillation
Medications: Metoprolol, warfarin
Chief Complaint: Sudden onset right-sided weakness and speech difficulty
History: Hypertension, atrial fibrillation
Medications: Metoprolol, warfarin
Chief Complaint: Sudden onset right-sided weakness and speech difficulty
Margaret was eating breakfast when she suddenly dropped her fork. Her husband noticed her face drooping on the right side and she was unable to speak clearly. She was brought to hospital within 2 hours of symptom onset. Last seen well was 90 minutes ago.
Physical Examination
Blood Pressure
185/105
mmHg
Heart Rate
88
bpm (irregular)
GCS
14
E4V4M6
Temperature
36.8
°C
Neurological:
• Right facial droop (lower face)
• Right arm and leg weakness (2/5 strength)
• Expressive aphasia - unable to form words, understands speech
• Right hemisensory loss
• Right homonymous hemianopia (visual field cut)
• Hyperreflexia on right side, positive Babinski
• Right facial droop (lower face)
• Right arm and leg weakness (2/5 strength)
• Expressive aphasia - unable to form words, understands speech
• Right hemisensory loss
• Right homonymous hemianopia (visual field cut)
• Hyperreflexia on right side, positive Babinski
Imaging
CT Head: No hemorrhage, early hypodensity in left middle cerebral artery (MCA) territory
CT Angiography: Occlusion of left MCA M1 segment (main trunk)
CT Angiography: Occlusion of left MCA M1 segment (main trunk)
Clinical Reasoning Questions
1. Why does Margaret have weakness of the lower right face but not the forehead?
Correct! Bilateral vs unilateral innervation
This is a key neuroanatomical concept:
• Upper face (forehead): Receives bilateral cortical innervation from both hemispheres
• Lower face: Receives only contralateral innervation from the opposite hemisphere
• In an upper motor neuron lesion (stroke), only the lower face is affected on the opposite side
• This differentiates UMN lesions (stroke) from LMN lesions (Bell's palsy - affects entire ipsilateral face)
Margaret has left MCA stroke affecting right lower face only.
This is a key neuroanatomical concept:
• Upper face (forehead): Receives bilateral cortical innervation from both hemispheres
• Lower face: Receives only contralateral innervation from the opposite hemisphere
• In an upper motor neuron lesion (stroke), only the lower face is affected on the opposite side
• This differentiates UMN lesions (stroke) from LMN lesions (Bell's palsy - affects entire ipsilateral face)
Margaret has left MCA stroke affecting right lower face only.
2. Margaret has expressive aphasia. Which brain area is affected?
Correct! Broca's area in the inferior frontal gyrus
Broca's area: Located in the dominant hemisphere (usually left), controls speech production. Lesion causes expressive (motor) aphasia - inability to speak fluently while comprehension is intact.
Wernicke's area: Located in the posterior superior temporal lobe, controls language comprehension. Lesion causes receptive (sensory) aphasia - fluent but nonsensical speech with poor comprehension.
Both Broca's and Wernicke's areas are supplied by the MCA, explaining why MCA strokes commonly affect language.
Broca's area: Located in the dominant hemisphere (usually left), controls speech production. Lesion causes expressive (motor) aphasia - inability to speak fluently while comprehension is intact.
Wernicke's area: Located in the posterior superior temporal lobe, controls language comprehension. Lesion causes receptive (sensory) aphasia - fluent but nonsensical speech with poor comprehension.
Both Broca's and Wernicke's areas are supplied by the MCA, explaining why MCA strokes commonly affect language.
3. Which artery territory explains all of Margaret's deficits (face, arm, leg weakness + aphasia)?
Correct! Left middle cerebral artery (MCA)
The MCA supplies:
• Motor cortex: Face, arm, hand areas (leg area supplied by ACA)
• Sensory cortex: Face and arm
• Broca's area: Speech production
• Wernicke's area: Language comprehension
• Optic radiations: Visual pathways (causing hemianopia)
ACA supplies medial frontal/parietal (leg weakness mainly). PCA supplies occipital lobe (vision). Basilar supplies brainstem.
The MCA supplies:
• Motor cortex: Face, arm, hand areas (leg area supplied by ACA)
• Sensory cortex: Face and arm
• Broca's area: Speech production
• Wernicke's area: Language comprehension
• Optic radiations: Visual pathways (causing hemianopia)
ACA supplies medial frontal/parietal (leg weakness mainly). PCA supplies occipital lobe (vision). Basilar supplies brainstem.
Bioscience Integration
The Ischemic Cascade
When blood flow is interrupted, neurons are injured through:
- Energy failure: ATP depletion within minutes
- Excitotoxicity: Glutamate accumulation, calcium influx
- Oxidative stress: Free radical production
- Inflammation: Microglial activation, cytokine release
- Apoptosis/necrosis: Cell death
The penumbra (area around the core infarct) is salvageable with rapid reperfusion.
Nursing Implications
- Time critical: "Time is brain" - thrombolysis window is 4.5 hours
- Positioning: Elevate head 30° to reduce ICP
- Swallowing: Screen before any oral intake (aspiration risk)
- Complications: Monitor for hemorrhagic transformation, cerebral edema
- Rehabilitation: Early mobilization, speech therapy, occupational therapy