What is the best course of action for a 28-year-old female, 23 weeks pregnant, presenting with a 5-hour history of numbness to the right side of her face and weakness with closing the right eye?

Acute Peripheral Facial Nerve Palsy (Bell's Palsy) in Pregnancy

This 28-year-old pregnant woman at 23 weeks gestation presenting with acute unilateral facial numbness and weakness with eye closure most likely has Bell's palsy (idiopathic peripheral facial nerve palsy), which requires immediate initiation of corticosteroids within 72 hours of symptom onset for optimal recovery, along with aggressive eye protection measures. 1

Clinical Localization and Diagnosis

The key distinguishing feature is that this is a peripheral seventh cranial nerve (facial nerve) palsy, NOT a central stroke, based on the following:

• Isolated facial symptoms with eye closure weakness indicates peripheral facial nerve involvement at or distal to the facial nucleus 1
• Absence of other neurological deficits (no limb weakness, no eye movement abnormalities beyond lid closure, no speech difficulties) argues strongly against stroke 1, 2, 3
• Central (stroke) facial weakness spares the forehead and eye closure because of bilateral cortical innervation to the upper facial muscles, whereas peripheral facial nerve palsy affects the entire half of the face including inability to close the eye 1, 4

Critical Red Flags That Would Indicate Stroke Instead:

• Eye movement abnormalities (inability to move eye in specific directions) would indicate pontine stroke 1
• Limb weakness on the same side as facial symptoms would indicate cortical/subcortical stroke 2, 3
• Aphasia or language difficulties would indicate left hemisphere stroke 2
• Multiple cranial nerve involvement would indicate brainstem pathology 1, 4

Immediate Management

Corticosteroid Therapy (First Priority)

• Initiate oral prednisone 60-80 mg daily for 7 days within 72 hours of symptom onset for best outcomes 1
• Pregnancy is NOT a contraindication to corticosteroids for Bell's palsy, as the benefits of preventing permanent facial paralysis outweigh theoretical fetal risks 5
• Corticosteroids are Pregnancy Category C but have extensive safety data in pregnancy for other conditions 5

Eye Protection (Equally Critical)

• Implement aggressive corneal protection immediately to prevent exposure keratopathy, which can cause permanent vision loss 1, 6
• Artificial tears every 1-2 hours while awake 6
• Ophthalmic lubricating ointment at bedtime 6
• Eye taping or patching at night if complete eye closure is impossible 1, 6
• Consider moisture chamber or protective eyewear during the day 6

Diagnostic Workup

No imaging is required for typical Bell's palsy presentation unless atypical features are present 1, 4:

Proceed directly to treatment if:

• Acute onset over hours
• Unilateral complete facial weakness
• No other neurological deficits
• No history of trauma
• No systemic symptoms (fever, weight loss, rash)

Obtain urgent MRI brain with contrast if ANY of these features:

• Gradual onset over days to weeks (suggests tumor or other mass lesion) 7
• Bilateral facial weakness 4
• Other cranial nerve involvement 1, 4
• Vesicular rash (consider Ramsay Hunt syndrome from herpes zoster) 4
• Recurrent episodes 4
• Failure to improve within 3-4 weeks 1

Pregnancy-Specific Considerations

• Bell's palsy is 3 times more common in pregnancy, particularly in the third trimester and early postpartum period 5
• Prognosis is similar to non-pregnant patients with appropriate treatment 5
• Avoid antiviral agents unless herpes zoster is confirmed, as routine antivirals for Bell's palsy have limited evidence and pregnancy safety data 5

Expected Recovery and Follow-up

• 70-85% of patients recover completely within 3-6 months with corticosteroid treatment 1
• Schedule ophthalmology follow-up within 1 week to assess corneal integrity 6
• Neurology follow-up in 2-4 weeks to assess recovery trajectory 1
• If no improvement by 3-4 weeks, obtain MRI to exclude alternative diagnoses 1, 7

Critical Pitfalls to Avoid

• Do NOT delay corticosteroids waiting for imaging or specialist consultation—treatment efficacy drops dramatically after 72 hours 1
• Do NOT dismiss eye protection as secondary—corneal ulceration can develop within 24-48 hours and cause permanent vision loss 6
• Do NOT assume this is stroke based solely on facial symptoms—the pattern of weakness (complete hemifacial including forehead) localizes this peripherally 1, 4
• Do NOT withhold corticosteroids due to pregnancy—untreated Bell's palsy carries 15-30% risk of permanent facial paralysis, which far outweighs theoretical fetal risks 5, 1