What causes facial twitching and how is it treated?

Facial Twitching: Diagnosis and Treatment

Facial twitching is most commonly caused by benign etiologies like hemifacial spasm or Bell's palsy, but can also indicate serious underlying conditions; treatment should be directed at the specific cause, with botulinum toxin injections being the most effective treatment for persistent cases. 1, 2

Causes of Facial Twitching

Facial twitching can be categorized based on etiology:

Common Benign Causes:

• Hemifacial spasm (HFS): Characterized by tonic and clonic contractions of muscles innervated by the ipsilateral facial nerve, typically starting in one eyelid and spreading to other facial muscles 2
• Chronic eyelid twitching (CET): Persists longer than 2 weeks, more common in women and during cold weather 3
• Bell's palsy: Acute unilateral facial nerve paresis or paralysis with onset in less than 72 hours 4, 5

Secondary Causes:

• Vascular compression: Tortuous vertebrobasilar arteries compressing the facial nerve root exit zone 6, 2
• Trauma: Blunt injury to facial nerve branches 7
• Neurological disorders: Including multiple sclerosis, stroke, or brain tumors 5
• Medication side effects: Tardive dyskinesia from antipsychotic medications 4

Red Flags (requiring immediate evaluation):

• Facial numbness or weakness
• Progressive symptoms
• Bilateral involvement
• Associated hearing loss or tinnitus
• Other neurological symptoms 1

Diagnostic Approach

1. Thorough history and physical examination:

   • Onset (sudden vs. gradual)
   • Duration and progression
   • Unilateral vs. bilateral involvement
   • Associated symptoms 4

2. Rule out serious causes:

   • Brain tumors
   • Stroke
   • Parotid tumors
   • Recent head/facial trauma
   • Infections 4

3. Diagnostic testing (when indicated by history/exam):

   • MRI: Preferred for evaluating facial nerve course and potential compression
   • Electrophysiological studies: May show synkinesis, delayed or absent R2 response in blink reflex, or prolonged facial nerve latency 3
   • Laboratory testing is not routinely recommended 4

Treatment Options

For Hemifacial Spasm and Persistent Facial Twitching:

• Botulinum toxin injections: First-line treatment with high efficacy and few disabling side effects 8, 2
  • Administered into affected muscles
  • Effects last 3-4 months
  • Should not be administered more frequently than every three months 8

For Bell's Palsy:

• Oral corticosteroids: Strongly recommended within 72 hours of symptom onset 1
• Eye protection: Crucial for patients with incomplete eyelid closure (artificial tears, ocular ointment, eye patching) 1
• Antiviral therapy: May be considered in combination with steroids but offers minimal additional benefit 1

For Secondary Causes:

• Treatment directed at underlying condition:
  • Microvascular decompression for vascular compression
  • Anticonvulsants for paroxysmal kinesigenic dyskinesia
  • Discontinuation of offending medications for drug-induced cases 1

Special Considerations

1. Botulinum toxin administration:

   • Potency units are specific to each preparation and not interchangeable between products
   • Proper injection technique is essential to avoid complications like eyelid ptosis
   • Lateral corrugator injections should be placed at least 1 cm above the bony supraorbital ridge 8

2. Monitoring and follow-up:

   • Patients should be reevaluated if symptoms worsen or don't improve after 3 months
   • For tardive dyskinesia, assessment for abnormal movements should occur every 3-6 months using the Abnormal Involuntary Movement Scale 4

3. Prognosis:

   • Bell's palsy: 70-94% chance of complete recovery
   • Hemifacial spasm: Typically chronic but controllable with botulinum toxin
   • Secondary causes: Prognosis depends on underlying condition 1

Differential Diagnosis

Important to distinguish facial twitching from:

• Psychogenic facial spasm
• Facial tic
• Facial myokymia
• Blepharospasm
• Tardive dyskinesia 2

The clinical pattern, electrophysiological findings, and response to treatment can help differentiate between these conditions and guide appropriate management.