A patient develops new left‑side weakness minutes after initial symptoms—what is the appropriate emergency evaluation and treatment?

Emergency Management of Acute Left-Sided Weakness

A patient developing new left-sided weakness minutes after initial symptoms requires immediate activation of stroke protocols with urgent non-contrast CT brain imaging and CT angiography to determine eligibility for intravenous alteplase (within 4.5 hours) and/or endovascular thrombectomy (within 6-24 hours depending on imaging criteria). 1

Immediate Actions (Door-to-Imaging Target: <25 minutes)

Initial Assessment

• Airway, breathing, circulation - Stabilize any life-threatening conditions first 1
• NIHSS score - Quantify stroke severity immediately; this guides treatment decisions and prognosis 1, 2
• Time last known well - This is the critical determinant for treatment eligibility, not when symptoms were discovered 1
• Blood glucose - Check immediately; hypoglycemia (<60 mg/dL or 3.3 mmol/L) mimics stroke and requires IV dextrose 1, 3

Concurrent Vital Signs Monitoring

• Blood pressure every 15 minutes until stable 4
• Oxygen saturation (maintain ≥94%) 3
• Temperature, heart rate/rhythm 1

Essential Laboratory Tests (Do NOT delay imaging)

• Complete blood count, electrolytes, creatinine 1
• INR, aPTT - Critical for alteplase eligibility 1
• Random glucose 1
• Troponin - Stroke and MI can occur simultaneously 2

Critical Pitfall: These labs should be drawn but must not delay brain imaging or treatment decisions. 1

Neuroimaging Protocol

Within 4.5 Hours of Symptom Onset

Immediate non-contrast CT (NCCT) brain - This is the minimum required imaging to:

• Exclude intracranial hemorrhage (absolute contraindication to alteplase) 1, 5
• Identify early ischemic changes (>1/3 MCA territory hypodensity is strong contraindication) 5, 2
• Rule out stroke mimics 1

Within 6 Hours of Symptom Onset (or up to 24 hours for selected patients)

NCCT + CT angiography (CTA) from aortic arch to vertex - Required to:

• Identify large vessel occlusion for endovascular thrombectomy eligibility 1
• Visualize both extracranial and intracranial circulation 1, 4

Beyond 6 Hours (up to 24 hours)

Advanced imaging required: CTA + CT perfusion (CTP) or MRI with diffusion-weighted imaging (DWI) and perfusion to demonstrate:

• Salvageable penumbra (perfusion-diffusion mismatch) 1
• Small ischemic core relative to hypoperfused tissue 1

Note: The 2018 Canadian guidelines emphasize that highly selected patients may benefit from EVT up to 24 hours using these advanced imaging criteria. 1

Treatment Decision Algorithm

If Presenting Within 4.5 Hours AND Imaging Shows No Hemorrhage:

Intravenous Alteplase Eligibility (refer to NINDS criteria):

• Dose: 0.9 mg/kg (maximum 90 mg total)
  • 10% as IV bolus over 1 minute
  • 90% as IV infusion over 60 minutes 1, 6
• Target door-to-needle time: <60 minutes in 90% of patients, median 30 minutes 1
• Blood pressure requirement: Must be <185/110 mmHg before and during treatment 1

Critical Contraindications to Note:

• Intracranial hemorrhage on imaging 1, 5
• Frank hypodensity >1/3 MCA territory 5, 2
• Current use of direct oral anticoagulants (DOACs) - alteplase should NOT routinely be given; consider EVT instead 1
• INR >1.7, aPTT elevated, platelet count <100,000 1

If Large Vessel Occlusion Identified on CTA:

Endovascular Thrombectomy (EVT) Criteria:

• Within 6 hours: Proximal anterior circulation occlusion (ICA, M1, proximal M2) 1
• 6-24 hours: Requires demonstration of salvageable tissue on advanced imaging (CTP or MRI) 1
• Can be performed with or without prior alteplase 1

The evidence strongly supports that EVT benefit decreases with time - every minute counts, with an estimated 1.9 million brain cells dying per minute. 1

Blood Pressure Management

For Alteplase Candidates:

• Must achieve BP <185/110 mmHg before administering alteplase 1
• Use IV labetalol or nicardipine to rapidly lower BP 1
• Monitor BP every 15 minutes during and for 2 hours after infusion, then every 30 minutes for 6 hours 1

For Non-Alteplase Candidates:

• Only treat if SBP >220 mmHg or DBP >120 mmHg 1
• Avoid aggressive BP lowering - may worsen cerebral perfusion 1

Special Considerations

If Uncertainty Exists:

Urgently consult stroke specialist (on-site or via telestroke) when:

• Unclear if patient meets alteplase criteria 1
• Uncertainty about CT interpretation - consult radiologist 1
• Patient on DOACs - specialized testing and reversal agents may allow treatment in comprehensive centers 1

Hospital Inpatients:

If stroke occurs in an existing inpatient, they should receive the same rapid evaluation and access to acute treatments (alteplase and EVT) as ED patients. 1

Post-Treatment Monitoring:

• 24-hour post-thrombolysis CT scan required before starting antiplatelet agents 1
• Monitor for angioedema (treat with antihistamines, glucocorticoids, airway management) 1
• Watch for hemorrhagic transformation 1

Common Pitfalls to Avoid

1. Delaying imaging for laboratory results - Labs should not delay CT scanning 1
2. Waiting for "complete" workup - Time is brain; treat first, investigate etiology later 1
3. Assuming "minor" symptoms don't need urgent treatment - Left-sided weakness is disabling and warrants full acute stroke evaluation 1
4. Missing the extended time windows - Selected patients benefit from EVT up to 24 hours with appropriate imaging 1
5. Giving alteplase to patients on DOACs - This is contraindicated; consider EVT instead 1
6. Over-aggressive BP lowering in non-thrombolysis candidates - May worsen ischemia 1

The overarching principle: Every minute of delay increases disability and mortality. Activate stroke protocols immediately, obtain imaging urgently, and treat within the shortest possible timeframe. 1, 3