How should I evaluate and manage a patient who presents to the emergency department with acute left-sided facial drooping?

Acute Management of Left-Sided Facial Drooping in the Emergency Department

Activate stroke code immediately and obtain urgent MRI with diffusion-weighted imaging (DWI), as facial droop with unilateral weakness is highly suggestive of acute stroke and requires time-critical evaluation for thrombolysis within 4.5 hours, even if initial CT is normal. 1

Immediate Assessment and Documentation

• Document exact time of symptom onset (or last known well time if unwitnessed) to determine eligibility for thrombolysis (4.5-hour window) and endovascular therapy (up to 24-hour window in selected patients). 2, 1

• Perform structured neurological assessment using the National Institutes of Health Stroke Scale (NIHSS) to quantify deficit severity and guide treatment decisions. 1

• Apply validated stroke screening tools such as the Cincinnati Prehospital Stroke Scale (CPSS) or Face-Arm-Speech-Time (FAST) scale, which have pooled sensitivity of 80% and specificity of 42% for stroke detection. 2

• Assess for specific high-risk features including unilateral arm/leg weakness, speech disturbance, or facial drooping—these presentations classify the patient as VERY HIGH risk for stroke requiring immediate advanced imaging within 24 hours. 2

Critical Imaging Algorithm

Obtain brain MRI with DWI sequences urgently, as this is the gold standard for detecting acute ischemic stroke and can identify infarction within minutes of onset, while CT may remain normal in early stroke. 1

• If MRI is unavailable or contraindicated, obtain non-contrast CT head immediately to rule out hemorrhage, followed by CT angiography (CTA) from aortic arch to vertex to identify large vessel occlusion amenable to endovascular therapy. 2, 1

• Include MRA or CTA from arch to vertex in all cases to evaluate for large vessel occlusion, as this determines eligibility for mechanical thrombectomy with extended treatment windows. 2, 1

• Obtain 12-lead ECG without delay to assess for atrial fibrillation as a potential embolic source. 2, 1

Time-Sensitive Treatment Considerations

• Assess for IV alteplase eligibility if presenting within 4.5 hours of symptom onset (dose: 0.9 mg/kg, with 10% given over 1 minute and remainder over 59 minutes), as this improves functional outcomes in acute ischemic stroke. 1, 3

• Blood pressure must be reduced to <185/110 mmHg before thrombolysis to avoid hemorrhagic complications, as elevated blood pressure is a contraindication to alteplase administration. 2

• Evaluate for endovascular therapy if large vessel occlusion is identified, with treatment windows extending to 24 hours in highly selected patients based on advanced neurovascular imaging. 2, 1

• Transfer immediately to a stroke center if your facility lacks stroke treatment capabilities, as EMS should bypass hospitals without stroke resources to reach the closest capable facility. 2

Critical Diagnostic Pitfalls to Avoid

Do not assume Bell's palsy without MRI, as isolated facial palsy can be the presenting sign of pontine or frontal lobe stroke, and misdiagnosis delays critical stroke treatment. 1, 4

• Never rely on CT alone to rule out stroke, as normal CT does not exclude acute ischemic stroke, particularly in posterior circulation strokes where MRI sensitivity is vastly superior. 1

• Do not discharge patients with facial droop presenting within 48 hours without advanced imaging and comprehensive stroke workup, as they are at VERY HIGH risk (3-6%) for stroke within the first 1-4 weeks. 2, 1

• Consider stroke mimics but do not delay imaging: myasthenia gravis can present with unilateral ptosis and facial droop without fluctuating weakness, and thrombotic thrombocytopenic purpura can present as stroke with thrombocytopenia. 5, 6

• In patients under 35 years, perform point-of-care cardiac ultrasound to evaluate for embolic sources such as atrial masses or thrombi, as these are more common causes in younger stroke patients. 7

Special Considerations

• If patient is on anticoagulation, admit for 24-hour observation with repeat imaging due to delayed hemorrhage risk of 1.4-4.5%. 1

• In patients over 50 years with visual symptoms or retinal findings, urgently obtain ESR and CRP to rule out giant cell arteritis, which requires immediate high-dose IV methylprednisolone (1g daily for 3 days) to prevent contralateral eye involvement. 3

• Up to 24% of patients with retinal artery occlusion have concurrent silent brain infarctions on DWI-MRI, reinforcing the need for comprehensive brain imaging even with isolated visual symptoms. 2, 3

• In pediatric patients (age <16), maintain high index of suspicion despite low incidence (0.6-7.9/100,000), and assess for recent trauma to major vessels including clavicular injuries that can cause vascular insult. 8