UMN Facial Palsy (Central facial palsy)

Clinical features

• Weakness of the contralateral lower face
  • Flattened nasolabial fold
  • Drooping of angle of mouth
  • Difficulty showing teeth or puffing out cheek
• Forehead is relatively spared
  • Can wrinkle forehead
  • Can raise eyebrows
  • Can usually close the eye tightly

Why is the forehead spared?

• Upper part supplying forehead and eye-closing muscles, with bilateral cortical innervation
• Lower part supplying lower facial muscles, with mainly contralateral cortical innervation

Site and side

Associated findings

• Contralateral arm and/or leg weakness
• Hyperreflexia and extensor plantar response
• Dysarthria
• Aphasia, if dominant hemisphere involved
• Hemisensory loss
• Visual-field defect

UMN versus LMN facial palsy

UMN facial palsy causes contralateral weakness of the lower face with sparing of the forehead, because the upper facial nucleus receives bilateral corticobulbar innervation, whereas the lower facial nucleus receives predominantly contralateral input.

1. Treat as acute stroke until proven otherwise

• Establish time last known well, check glucose, perform neurological examination.
• Urgent non-contrast CT head to exclude hemorrhage, with vascular and perfusion imaging when indicated.
• Admit to a stroke unit and identify the cause: ischemic stroke, hemorrhage, tumor, demyelination, etc.

2. Reperfusion treatment for eligible ischemic stroke

• IV thrombolysis for eligible patients within the appropriate time window, including selected extended-window cases guided by imaging.
• Mechanical thrombectomy for eligible large-vessel occlusion, with selection based on vessel imaging and time/imaging criteria.

3. Secondary prevention after ischemic stroke

• Antiplatelet therapy or anticoagulation for cardioembolic disease such as atrial fibrillation
• Control hypertension, diabetes, and lipids
• High-intensity statin when indicated
• Smoking cessation, physical activity, healthy diet
• Carotid evaluation and carotid revascularization in selected symptomatic carotid stenosis

4. Rehabilitation

• Early physiotherapy, occupational therapy, and speech/swallow assessment if deficits coexist
• Facial exercises and functional retraining may be used when facial weakness persists
• Treat communication, feeding, mood, and social effects of stroke

Important distinction

Treatment of UMN facial palsy is treatment of its cause, usually acute stroke management with rapid imaging, reperfusion therapy when eligible, stroke-unit care, secondary prevention, and rehabilitation. Steroids are not indicated unless there is another specific diagnosis.

Bell palsy treatment

1. Oral corticosteroids: first-line

• Prednisolone 50-60 mg orally once daily for 5 days, then taper over 5 days
  or
• Prednisolone 50 mg daily for 10 days

2. Eye protection: essential if eye closure is incomplete

• Artificial tears/lubricating drops frequently during the day
• Lubricating eye ointment at night
• Tape the eyelid closed or use an eye patch during sleep
• Protective glasses outdoors

3. Antivirals: not routine monotherapy

• Do not use aciclovir/valaciclovir alone instead of corticosteroids.
• Antiviral therapy may be considered with steroids in severe or complete Bell palsy, though the extra benefit is modest and evidence is less certain.
• If there is a painful vesicular rash in or around the ear, consider Ramsay Hunt syndrome, where combined antiviral plus steroid treatment is generally used urgently.

4. Supportive care and follow-up

• Analgesia for ear or facial pain, for example paracetamol or an NSAID if appropriate.
• Facial physiotherapy may be helpful in persistent weakness, especially chronic cases or synkinesis, but it is not a substitute for early steroids.
• Facial nerve decompression surgery is not routinely recommended.

Refer or reassess urgently if

• Forehead is spared, or there are limb weakness, speech disturbance, severe headache, diplopia, or ataxia: possible central stroke
• Facial weakness is progressive beyond 3 weeks
• No improvement by about 3 weeks, or incomplete recovery by 3 months
• Recurrent or bilateral palsy
• Hearing loss, marked vertigo, ear vesicles, systemic illness, trauma, or a parotid mass

Treat Bell palsy with oral prednisolone within 72 hours, eye lubrication and protection, analgesia, and follow-up. Add an antiviral only selectively, particularly in severe palsy or suspected Ramsay Hunt syndrome.