Hemifacial Spasm

Hemifacial spasm (HFS) is a neuromuscular condition causing involuntary twitching, contractions, and spasms of the muscles on one side of the face. Unlike blepharospasm, it affects one side only and involves muscles beyond just the eyelids. It's most commonly caused by a blood vessel compressing the facial nerve.

Understanding Hemifacial Spasm

The facial nerve (seventh cranial nerve) controls the muscles of facial expression. When this nerve is irritated, usually by compression from a nearby blood vessel, the muscles it controls start firing involuntarily, causing the characteristic twitching and spasms.

Symptoms

Typical Progression

1. Starts around the eye—twitching of eyelid
2. Spreads downward—to cheek, mouth, jaw muscles
3. May involve neck muscle (platysma)
4. Always same side of face

Characteristics

• Irregular, involuntary muscle contractions
• Twitching, pulling, spasms
• May cause eye to squeeze shut (similar to ptosis in appearance)
• Mouth may pull to the side
• Present during sleep (unlike blepharospasm)
• Triggered by stress, fatigue
• May affect hearing (ear muscle involvement)
• Often causes light sensitivity from eye closure

Severity Range

• Mild: occasional twitching, minimally bothersome
• Moderate: frequent spasms affecting function
• Severe: near-constant contractions, significantly disabling

Causes

Primary (Most Common)

Vascular compression

• Blood vessel (usually artery) pressing on facial nerve
• Where nerve exits brainstem
• Causes abnormal nerve signals
• Anterior inferior cerebellar artery most common culprit

Secondary (Less Common)

• Tumor near facial nerve
• Bell's palsy sequela
• Brainstem lesions (stroke, MS)
• Arteriovenous malformation
• After skull base surgery

Diagnosis

Clinical Features

• Unilateral facial twitching/spasms
• Typical spread pattern (eye to lower face)
• No other neurological abnormalities

Differentiating From Other Conditions

Condition	Key Features
Hemifacial spasm	One side, includes lower face, persists during sleep
Blepharospasm	Both eyes, eyelids only, resolves during sleep
Facial myokymia	Continuous undulating movement, not spasms
Eyelid myokymia	Brief twitching, one lid, benign, temporary
Tics	Suppressible, may have premonitory urge

Imaging

MRI brain with special sequences

• FIESTA/CISS sequences show nerve-vessel relationship
• Rules out tumor or other structural cause
• May see vessel loop at nerve root entry zone

Treatment

Botulinum Toxin Injections

First-line treatment for most patients

• Injected into affected facial muscles
• Weakens muscles to reduce spasms
• 85-95% get significant improvement
• Lasts 3-4 months
• Need repeat injections
• Well tolerated, low risk

Side effects:

• Temporary facial weakness
• Droopy mouth corner
• Dry eye
• Bruising

Microvascular Decompression Surgery

Definitive treatment option

• Surgical separation of blood vessel from facial nerve
• Places cushion between vessel and nerve
• Potentially curative (no more injections needed)
• 85-90% success rate

Considerations:

• Brain surgery with general anesthesia
• Small risks (hearing loss, facial weakness, rare serious complications)
• Usually reserved for:
  • Patients who want potential cure
  • Botox failures or intolerance
  • Younger patients with long expected lifespan

Oral Medications

• Generally not very effective
• Sometimes tried for mild cases
• Carbamazepine, baclofen, gabapentin
• May reduce frequency somewhat

Living with Hemifacial Spasm

Practical Tips

• Manage stress and fatigue
• Get adequate sleep
• Avoid excessive caffeine
• Wear sunglasses to reduce embarrassment
• Be open with others about the condition

Driving

• Usually safe to drive
• May be distracting but not dangerous
• Discuss with doctor if concerned

Social Impact

• Can be embarrassing or socially uncomfortable
• Most people cope well with treatment
• Support groups available

Prognosis

With Treatment

• Most achieve good control with Botox
• Surgery can be curative
• Quality of life usually good

Without Treatment

• May worsen over time
• Rarely remits spontaneously
• Not dangerous but bothersome

Natural History

• Doesn't become bilateral
• Doesn't cause permanent facial weakness
• Benign in terms of health (but affects quality of life)

Frequently Asked Questions

Is hemifacial spasm dangerous?

The condition itself is not dangerous to your health. However, it can significantly affect quality of life through embarrassment and functional impairment. The underlying cause (usually vascular compression) is also benign.

Will it spread to the other side of my face?

No. Hemifacial spasm remains unilateral. If you develop spasms on the other side, that would be a different condition (like blepharospasm) requiring re-evaluation.

Should I have surgery or Botox?

This is a personal decision weighing the desire for potential cure (surgery) against the simplicity and safety of ongoing injections (Botox). Younger patients with severe symptoms often consider surgery. Many patients are well-controlled with Botox indefinitely.

Can hemifacial spasm go away on its own?

Rarely. Spontaneous remission occurs in less than 10% of cases. Most patients need ongoing treatment.

What's the difference between this and a facial tic?

Tics are partially voluntary—you feel an urge and can suppress them temporarily. Hemifacial spasm is completely involuntary and cannot be suppressed by willpower. Tics are also often associated with other movements or vocalizations.

References