What are the symptoms and management of a moderate-sized acute infarct involving the left cerebral hemisphere?

Symptoms of Moderate-Sized Acute Left Hemispheric Infarct

A moderate-sized acute infarct involving the left cerebral hemisphere typically presents with right-sided motor weakness, right-sided sensory loss, and aphasia, with the specific symptom constellation depending on whether the middle cerebral artery (MCA) or other vascular territories are affected. 1

Cardinal Clinical Features

Motor and Sensory Deficits

• Right-sided weakness (hemiparesis or hemiplegia) is the hallmark finding, as the left hemisphere controls the contralateral side of the body 1, 2
• Upper extremity motor deficits occur in approximately 77% of acute stroke presentations 2
• Right-sided paresthesia or sensory loss accompanies the motor deficits in left MCA territory infarction 1

Language Dysfunction

• Aphasia is expected in left hemisphere infarcts affecting language-dominant areas in right-handed individuals, occurring in approximately 23% of acute stroke presentations 1, 2
• Wernicke's aphasia or global aphasia without hemiparesis is particularly suggestive of cardioembolic infarction 3
• Aphasia may also occur in ambidextrous or left-handed individuals with right hemisphere infarcts 1

Visual Field Defects

• Left homonymous hemianopsia (visual field loss affecting the left visual field in both eyes) can occur with left hemisphere infarction involving posterior territories 1
• Monocular blindness affecting the left eye may occur if the left internal carotid artery is involved 1

Altered Consciousness

• Altered level of consciousness occurs in approximately 19% of cases, particularly with larger infarcts 2
• Decreased level of consciousness at onset is more suggestive of cardioembolic mechanism 3

Behavioral and Cognitive Changes

• Executive dysfunction and behavioral changes may occur with left frontal lobe involvement 2
• Left-sided neglect and abnormal visual-spatial ability are more typical of right hemisphere infarction 1

Critical Management Considerations

Immediate Triage and Monitoring

• Admit to intensive care or stroke unit with neuromonitoring capabilities attended by neurointensivists or vascular neurologists for moderate-sized infarcts 1, 2
• Early neurosurgical consultation should be obtained to facilitate planning for potential decompressive surgery if deterioration occurs 1, 2
• Frequent assessment of level of arousal and pupillary function is necessary to detect early signs of cerebral swelling 2

Risk of Cerebral Edema

• Frank hypodensity on head CT within the first 6 hours, involvement of one-third or more of the MCA territory, and early midline shift predict cerebral edema (Class I; Level of Evidence B) 1
• MRI DWI volumes ≥80 mL within 6 hours predict rapid fulminant course (Class I; Level of Evidence B) 1
• Serial CT findings in the first 2 days are useful to identify patients at high risk for developing symptomatic swelling 1

Signs of Clinical Deterioration

• Ipsilateral pupillary dysfunction with varying degrees of mydriasis is the most commonly described sign of deterioration 1
• Progressive worsening of limb power to extensor posturing indicates brainstem compression 1
• Abnormal respiratory patterns signal impending herniation 1

Common Pitfalls to Avoid

• Do not assume lacunar presentation: Multiple lacunar infarcts make cardioembolic origin unlikely, but a moderate-sized territorial infarct suggests large vessel or cardioembolic mechanism 3
• Do not delay neurosurgical consultation: Early involvement is critical as deterioration from cerebral edema can occur rapidly, particularly in the first 2-5 days 1
• Do not routinely place ICP monitors: ICP monitoring has limited value in supratentorial hemispheric infarcts, as deterioration results from midline shift rather than globally increased ICP 1
• Do not withhold DVT prophylaxis: Subcutaneous heparin or low-molecular-weight heparin is necessary despite risk of hemorrhagic transformation 1, 2