What are the typical clinical findings and acute management for an acute right middle cerebral artery (MCA) stroke?

Right Middle Cerebral Artery Stroke: Clinical Findings and Acute Management

Typical Clinical Presentation

A right MCA stroke produces left-sided hemiparesis (arm > leg pattern), left hemisensory loss, left homonymous hemianopsia, and left-sided neglect syndrome—the neglect being the hallmark feature that distinguishes right from left hemisphere strokes. 1

Motor and Sensory Deficits

• Left-sided weakness with characteristic arm > leg pattern due to the motor homunculus representation in the MCA territory 1
• Left facial droop affecting the lower face 1
• Left hemisensory loss affecting all sensory modalities (pain, temperature, proprioception, vibration) 1
• Loss of cortical sensory functions including stereognosis, graphesthesia, and two-point discrimination on the left side 1

Visual and Spatial Deficits

• Left homonymous hemianopsia from involvement of the optic radiations 1
• Left-sided neglect syndrome (also called hemispatial neglect or hemi-inattention)—patients fail to attend to the left side of space, may ignore left-sided stimuli, and show marked rightward exploration bias even in free viewing tasks 1, 2
• Abnormal visual-spatial ability and impaired spatial processing 1
• Anosognosia (lack of awareness of deficits) may be present 1

Critical Diagnostic Pitfall

Eye-tracking studies reveal that 50% of right MCA stroke patients who score at ceiling on standard paper-and-pencil neglect screening tests still demonstrate significant leftward exploration deficits, meaning neglect is frequently missed by conventional bedside testing. 2 This has major implications because untreated neglect predicts poor functional recovery and severe difficulties in daily living 2.

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Acute Imaging Findings

Early CT Signs (Within 6 Hours)

Early CT signs are detectable in 82-94% of right MCA strokes within 6 hours, but initial CT can be completely normal in up to 25% of cases—clinical assessment remains paramount. 1, 3

Key early CT findings include:

• Hyperdense right MCA sign (visible thrombus in the vessel) 1, 4
• Loss of gray-white matter differentiation in the right insular cortex and basal ganglia 1
• Attenuation of the right lentiform nucleus (loss of normal density) 1
• Loss of the right insular ribbon (effacement of the insular cortex) 1
• Sulcal effacement in the right MCA territory 1

High-Risk Imaging Features

Involvement of >1/3 of the MCA territory on initial CT predicts poor outcomes and carries an 8-fold increased risk of hemorrhagic transformation with thrombolytic therapy—however, physician accuracy in detecting this finding is only 70-80%. 1 This represents a major clinical challenge in risk stratification 1.

Advanced Imaging

• CT angiography (CTA) should be performed to identify vessel occlusion location (M1, M2 segments) and guide endovascular therapy decisions 3, 5
• Perfusion CT can identify infarct core versus penumbra and predict malignant edema development 3
• MRI with diffusion-weighted imaging (DWI) is more sensitive than CT for small infarcts but should not delay treatment if the patient is otherwise eligible for thrombolysis 1

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Acute Management Algorithm

Immediate Reperfusion Therapy (Time-Critical)

Intravenous alteplase (0.9 mg/kg, maximum 90 mg) should be administered within 4.5 hours of symptom onset with a door-to-needle time <60 minutes; every 30-minute delay reduces the chance of good outcome by 8-14%. 5

IV Alteplase Eligibility

• Onset within 4.5 hours (or last known well time if wake-up stroke) 5
• No current anticoagulant use (contraindication) 5
• Blood pressure ≤185/110 mmHg before treatment 5
• No hemorrhage on CT 5

Endovascular Thrombectomy

Mechanical thrombectomy with stent retrievers is strongly indicated for right MCA M1 or proximal M2 occlusions, with treatment initiated within 6 hours of symptom onset (extending to 24 hours in selected patients with favorable imaging). 5

• Stent retrievers are preferred over other devices (Class I, Level A evidence) 5
• Combined stent retriever plus aspiration achieves faster and more complete reperfusion 5
• Technical goal: TICI 2b/3 reperfusion (near-complete to complete recanalization) 5
• Do not wait to assess IV alteplase response before pursuing thrombectomy—this delays treatment and worsens outcomes (Class III recommendation) 5

Blood Pressure Management

During and for 24 hours after thrombolytic therapy, maintain blood pressure ≤180/105 mmHg using rapidly titratable agents (labetalol or nicardipine) to reduce hemorrhagic transformation risk. 5

• In patients NOT receiving thrombolysis, avoid aggressive blood pressure lowering below 220/120 mmHg as cerebral perfusion may depend on higher pressures 5
• After mechanical thrombectomy, maintain BP ≤180/105 mmHg for 24 hours 5

Antiplatelet Therapy

Aspirin (160-325 mg) should be administered within 24-48 hours after stroke onset, but must be delayed for 24 hours in patients who received IV alteplase. 5, 3

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Monitoring for Life-Threatening Complications

Malignant Cerebral Edema

Peak swelling occurs 2-5 days after stroke onset; patients with complete right MCA territory infarction have 10-20% risk of developing malignant edema with brain herniation, which carries 50-70% mortality despite medical management. 3

Early Warning Signs

• Declining level of consciousness 3
• New pupillary changes (dilated right pupil from uncal herniation) 3
• Worsening motor deficits beyond initial presentation 3
• Respiratory pattern changes 3

Imaging Predictors of Malignant Edema

• >50% MCA territory hypodensity on CT within 12 hours 3
• Hyperdense MCA sign 3
• Compression of frontal horn of lateral ventricle 3
• Midline shift >5mm 3
• Subfalcine or uncal herniation 3

Medical Management of Elevated ICP

• Elevate head of bed 20-30 degrees to promote venous drainage 3
• Avoid hypoxemia, hypercarbia, and hyperthermia (all exacerbate edema) 3
• Restrict free water to avoid hypo-osmolar fluids 3
• Mannitol 0.25-0.5 g/kg IV every 6 hours (maximum 2 g/kg) as temporizing measure 3
• Avoid antihypertensive agents that cause cerebral vasodilation 3

Decompressive Hemicraniectomy

Decompressive hemicraniectomy performed within 48 hours reduces mortality by approximately 50% in patients <60 years old with malignant MCA infarction (OR for death 0.19,95% CI 0.13-0.51), though survivors often have moderate-to-severe disability. 3, 5

Selection Criteria for Surgery

• Age <60 years (strongest evidence; Class I, Level A) 3
• NIHSS >15 3
• Decreased level of consciousness 3
• CT showing >50% MCA territory involvement 3
• Surgery performed within 48 hours of symptom onset 3, 5

Outcomes in Older Patients (60-80 years)

In patients 60-80 years old, hemicraniectomy increases survival (38% vs 18% alive without severe disability, OR 2.91) but NO patients achieve good functional outcome (mRS 0-2)—most survivors require assistance with most activities of daily living. 3 Detailed discussions with families about survival with significant disability are essential 3.

Hemorrhagic Transformation

Hemorrhagic transformation occurs in 5% of untreated strokes but risk increases 8-fold with large infarcts (>1/3 MCA territory) treated with thrombolytics; it may present with sudden neurological worsening or be clinically silent. 3, 1

Immediate Actions for Suspected Hemorrhage

• Emergent head CT for any sudden worsening, severe headache, acute hypertension, nausea/vomiting 5
• Reverse anticoagulation if hemorrhage confirmed 5
• Neurosurgical consultation 5

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Post-Acute Monitoring Protocol

Serial neurological examinations every 15 minutes for the first 2 hours, then hourly for 24 hours; repeat head CT at 24 hours or immediately if clinical deterioration occurs. 5

Stroke Unit Care

• Admission to specialized stroke unit with neuromonitoring capabilities 3
• Continuous monitoring significantly reduces death and disability compared to intermittent vital sign checks 3
• Dysphagia screening within 4-24 hours by trained nurse (40-78% of stroke patients have dysphagia) 3
• Early mobilization and pulmonary hygiene to prevent pneumonia (14% incidence in first 7 days) 3

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Special Clinical Scenarios

Mild Symptoms Despite MCA Occlusion

A small subset of right MCA occlusion patients present with NIHSS ≤3 due to robust leptomeningeal collaterals; these patients often achieve functional independence without intervention and caution should be exercised before administering thrombolytic therapy. 6, 7 Perfusion imaging is required to identify truly "at risk" tissue in this population 7.

When Transfer for Thrombectomy Is Not Feasible

If mechanical thrombectomy is unavailable but intra-arterial access exists, intra-arterial fibrinolysis may be considered within 6 hours as a second-line option. 5 However, IV alteplase remains the priority treatment if the patient presents within 4.5 hours 5.