What causes facial twitching and how is it treated?

Causes and Treatment of Facial Twitching

Botulinum toxin injections are the first-line treatment for persistent facial twitching, particularly for conditions like hemifacial spasm, with high efficacy and minimal side effects. 1

Causes of Facial Twitching

Facial twitching can result from various conditions:

1. Primary Causes:

   • Hemifacial spasm (62% of cases) - typically caused by vascular compression of the facial nerve 2
   • Hereditary hemifacial spasm (2% of cases) 2

2. Secondary Causes (19% of cases): 2

   • Bell's palsy (11%) - acute unilateral facial nerve paresis/paralysis
   • Facial nerve injury (6%) - including blunt trauma 3
   • Demyelinating conditions
   • Cerebrovascular events
   • Paroxysmal Kinesigenic Dyskinesia (PKD)
   • Cerebellopontine angle lesions
   • Brainstem pathology
   • Temporal bone disorders
   • Parotid tumors

3. Mimickers (18% of cases): 2

   • Psychogenic facial movements
   • Facial tics
   • Dystonia (including blepharospasm)
   • Myoclonus
   • Hemimasticatory spasm
   • Tardive dyskinesia (medication-induced, particularly antipsychotics)

Diagnostic Approach

Red Flags Requiring Immediate Evaluation:

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

Diagnostic Testing:

• MRI - preferred for evaluating facial nerve course and potential compression
• High-resolution CT of temporal bone - complementary to MRI for evaluating osseous integrity
• Electrophysiological studies - can detect conduction defects in facial nerve pathway 4

Treatment Algorithm

1. For Persistent Facial Twitching (First-line):

• Botulinum toxin injections - highly effective with few disabling side effects 1, 5, 6
  • Administered no more frequently than every three months 5
  • Typical dose: 4 Units intramuscularly into each of five sites (total 20 Units) for glabellar lines 5
  • Injection technique is critical - avoid areas near levator palpebrae superioris to prevent eyelid ptosis 5

2. For Bell's Palsy:

• Oral corticosteroids - strongly recommended within 72 hours of symptom onset 1
• Antiviral therapy - may be considered in combination with steroids, but offers minimal additional benefit 1
• Eye protection - crucial for patients with incomplete eyelid closure:
  • Artificial tears
  • Ocular ointment
  • Eye patching or taping 1

3. For Paroxysmal Kinesigenic Dyskinesia:

• Anticonvulsant medications - often effective in controlling symptoms 1

4. For Secondary Causes:

• Treatment directed at underlying condition (e.g., tumor removal, vascular decompression) 1

Special Considerations

Gender Differences:

• Women are more vulnerable to chronic eyelid twitching than men (3:1 ratio) 4
• Higher rate of prolonged facial nerve latency in women (48.5% vs 38.2%) 4

Seasonal Variation:

• Chronic eyelid twitching tends to develop more in cold weather (61.27% of cases) 4

Botulinum Toxin Administration Precautions:

• Units are specific to each preparation and not interchangeable between products 5
• Reconstitute with preservative-free 0.9% Sodium Chloride Injection 5
• Use within 24 hours after reconstitution 5
• Contraindicated in individuals with known hypersensitivity to botulinum toxin or in the presence of infection at injection sites 5
• Monitor for spread of toxin effect beyond injection site, which can cause serious adverse effects 5

Follow-up and Monitoring

• Reevaluate if symptoms worsen or don't improve after 3 months 1
• For tardive dyskinesia, assess for abnormal movements every 3-6 months using the Abnormal Involuntary Movement Scale 1

Prognosis

• Bell's palsy: 70-94% chance of complete recovery, depending on severity 1
• Hemifacial spasm: typically chronic but controllable with botulinum toxin 1, 6
• Secondary causes: prognosis depends on underlying condition 1