What is the diagnosis and management of facial polyneuritis?

Diagnosis and Management of Facial Polyneuritis

Diagnosis

Facial polyneuritis requires systematic exclusion of identifiable causes through focused history and physical examination, with Bell's palsy representing the most common form when no other etiology is found. 1, 2

Critical History Elements

• Onset timing is the single most important diagnostic feature: Bell's palsy develops rapidly over less than 72 hours, while neoplastic or infectious causes progress gradually over days to weeks, and stroke presents with sudden onset often accompanied by other neurologic deficits 1

• Document specific features including:

  • Tick bite or insect bite history (suggests Lyme disease or tick-borne meningopolyneuritis) 3
  • Vesicular eruptions on the ear (suggests Ramsay Hunt syndrome from VZV reactivation) 4, 5
  • Travel to Lyme-endemic areas 1
  • Trauma history including temporal bone fracture or surgical injury 2
  • Ipsilateral ear or facial pain, taste disturbance, hyperacusis, dry eye or mouth 1, 2

Physical Examination Approach

• Systematically assess all facial nerve branches: test forehead elevation, eye closure, smile, and cheek puffing to distinguish peripheral (lower motor neuron) from central (upper motor neuron) lesions 1

• Forehead involvement is critical: forehead/frontalis weakness indicates peripheral lesion (Bell's palsy), while forehead sparing suggests central cause (stroke) 1, 2

• Examine for red flags requiring immediate investigation:

  • Bilateral facial weakness (never idiopathic—investigate for Lyme disease, sarcoidosis, or Guillain-Barré syndrome) 1, 2
  • Other cranial nerve involvement (indicates broader pathology such as cranial polyneuritis) 1, 5
  • Progressive weakness beyond 3 weeks (suggests alternative diagnosis) 6

• Grade severity using the House-Brackmann facial nerve grading system (Grade 1 = normal to Grade 6 = total paralysis) 6, 2

Diagnostic Testing Strategy

• Routine laboratory testing and diagnostic imaging are NOT recommended for typical Bell's palsy presentations 1, 6

• Order Lyme serology in endemic areas, with travel history, or if facial swelling/erythema is present 1

• MRI with and without contrast is the imaging test of choice when indicated for atypical presentations, no recovery after 3 months, or worsening symptoms 6, 2

• Electrodiagnostic testing (ENoG and EMG) should be offered to patients with complete facial paralysis, performed 3-14 days post-onset, with >10% nerve response amplitude indicating excellent prognosis 6

Management

Oral corticosteroids must be prescribed within 72 hours of symptom onset for patients 16 years and older to significantly improve facial nerve recovery. 1, 6

First-Line Treatment

• Prednisolone 50 mg daily for 10 days OR prednisone 60 mg daily for 5 days followed by a 5-day taper 1, 6

• Evidence demonstrates 83% recovery at 3 months with prednisolone versus 63.6% with placebo, and 94.4% recovery at 9 months versus 81.6% with placebo 6

• Antiviral monotherapy should NOT be prescribed for Bell's palsy 6

• Combination therapy with oral antivirals (acyclovir 400 mg five times daily for 10 days or valacyclovir) plus corticosteroids may be offered within 72 hours, though the added benefit is minimal 6

Mandatory Eye Protection

Eye protection is mandatory for all patients with impaired eye closure to prevent permanent corneal damage. 1, 6

• Lubricating drops every 1-2 hours while awake 1, 6
• Ophthalmic ointment at bedtime 1, 6
• Eye taping/patching with proper instruction (improper technique can cause corneal abrasion) 1, 6
• Sunglasses outdoors 1, 6
• Urgent ophthalmology referral for severe impairment with complete inability to close the eye 6

Special Etiologies Requiring Different Management

• Ramsay Hunt syndrome (VZV reactivation): Acyclovir administration plus corticosteroids; consider intravenous methylprednisolone and vitamin C as ancillary treatment for cranial polyneuritis 4, 5

• Tick-borne meningopolyneuritis (Lyme disease): Antibiotic treatment accelerates recovery from the typical 3-5 month course 3

• Acute otitis media with facial palsy: Myringotomy, appropriate antibiotics, and steroid therapy (steroids with antibiotics improve middle ear exudate resolution fourfold) 4

Follow-Up and Referral

• Mandatory reassessment or specialist referral at 3 months if facial recovery is incomplete 1, 6

• Immediate reassessment required for:

  • New or worsening neurologic findings at any point 1, 6
  • Development of ocular symptoms at any point 1, 6
  • Progressive weakness beyond 3 weeks 6

• Early follow-up at 1-2 weeks is valuable for monitoring recovery progress, ensuring adequate eye protection, and identifying complications 6

Therapies NOT Recommended

• Physical therapy has no proven benefit over spontaneous recovery 6
• Acupuncture has poor quality evidence with indeterminate benefit-harm ratio 6
• Electrical stimulation of facial muscles is not advised 4

Prognosis

• Patients with incomplete facial weakness have excellent prognosis with recovery rates up to 94% 6
• Approximately 70% of patients with complete paralysis recover completely within 6 months 6
• Most patients begin showing signs of recovery within 2-3 weeks 6
• Approximately 30% may experience permanent facial weakness with muscle contractures 6