Blepharospasm and Hemifacial Spasm

Overview & Definitions - Twitchy Twins Intro

• Blepharospasm (Benign Essential Blepharospasm - BEB): Involuntary, bilateral, repetitive, forceful eyelid closure. A focal dystonia affecting orbicularis oculi.
• Hemifacial Spasm (HFS): Unilateral, intermittent, involuntary contractions of muscles innervated by CN VII (facial nerve), typically starting around the eye.
• Primary Cause Distinction:
  • BEB: Mostly idiopathic; rarely secondary to drugs (e.g., neuroleptics) or basal ganglia lesions.
  • HFS: Often vascular compression of facial nerve root exit zone; less commonly tumors or post-Bell's palsy.

⭐ Blepharospasm typically bilateral, HFS unilateral.

Essential Blepharospasm (BEB) - Squeezy Eye Saga

• Bilateral, involuntary, progressive, spasmodic eyelid closure; idiopathic focal dystonia.
• Onset: Typically 50-70 years, F > M.
• Symptoms: ↑ blinking → forceful spasms, photophobia, difficulty keeping eyes open; can lead to functional blindness.
  • Aggravated by: Bright light, stress, fatigue.
  • Relieved by: Sleep, relaxation, sensory tricks (geste antagoniste).
• 📌 BEB: Bilateral Eyelid spasms, Botox is best.

⭐ Associated with Meige syndrome (oromandibular dystonia + blepharospasm).

• Treatment:
  • 1st line: Botulinum toxin A injections (orbicularis oculi, procerus, corrugator) q 3-4 months.
  • 2nd line: Surgical (limited myectomy) if botox fails.

Hemifacial Spasm (HFS) - One-Sided Winks

• Unilateral, involuntary, intermittent contractions (clonic/tonic) of facial nerve (CN VII) muscles.
• Etiology:
  • Primary (Idiopathic): Most common.

    ⭐ Most common cause: vascular compression of CN VII root exit zone (REZ) by aberrant vessel (AICA, PICA).

  • Secondary: Post-facial palsy, CPA tumors, MS, trauma.
• Clinical Features:
  • Starts orbicularis oculi, spreads ipsilaterally.
  • "Other Babinski sign": Eyebrow lift with forced eye closure.
  • Persists during sleep.
• Investigations:
  • MRI Brain/Brainstem: Rule out secondary causes.
• Treatment:
  • Botulinum toxin A injections (first-line).
  • Medical: Carbamazepine, gabapentin (less effective).
  • Surgical: Microvascular Decompression (MVD) if refractory_cases_with_identified_vascular_loop_

Differentiating Spasms - Twitch Tell-Tale

Treatment Toolkit - Taming The Twitches

⭐ Botulinum toxin A is the first-line treatment for both BEB and symptomatic HFS.

• Botulinum Toxin A (BoNT-A):
  • Gold standard; inhibits acetylcholine release.
  • Repeated injections every 3-4 months.
  • Target muscles: Orbicularis oculi, procerus, corrugator.
• Supportive Measures: Dark glasses, FL-41 tinted lenses, stress reduction.
• Surgical Options (for refractory cases):
  • BEB: Limited myectomy or frontalis suspension.
  • HFS: Microvascular Decompression (MVD) of facial nerve.

High‑Yield Points - ⚡ Biggest Takeaways

• Blepharospasm: Bilateral, involuntary orbicularis oculi spasms; can cause functional blindness. Botulinum toxin (BoNT-A) is first-line.
• Hemifacial Spasm: Unilateral facial muscle (CN VII) twitching; often from vascular compression of the facial nerve.
• Key differentiator: Hemifacial Spasm persists during sleep.
• BoNT-A is the primary treatment for both; Microvascular Decompression (MVD) is curative for Hemifacial Spasm.
• Meige Syndrome: Blepharospasm combined with oromandibular dystonia.