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This is repetitive, irregular clonic twitching of the muscles innervated by the facial nerve on one side of the face.
- The first symptom is usually an intermittent twitching of the eyelid muscle that can lead to forced closure of the eye.
- The spasm may then gradually spread to involve the muscles of the lower face, which may cause the mouth to be pulled to one side.
- Eventually the spasms involve all of the muscles on one side of the face almost continuously.
- It is a rare condition.
- All races are affected equally.
- The disorder occurs in both men and women, although it is more frequent in middle-aged or elderly women.
- Vascular compression most commonly. Most instances of hemifacial spasm (HFS) previously thought to be idiopathic, were probably caused by aberrant blood vessels compressing the facial nerve within the cerebellopontine angle.
- Facial nerve compression by mass or Paget's disease of bone.
- Brainstem lesion such as stroke or multiple sclerosis plaque.
- Secondary to trauma or Bell's palsy. 16% of Bell's palsy sufferers are left with hemifacial spasm.
- Secondary to otitis media with effusion.
The disorder presents in the fifth or sixth decade of life:
- Usually unilaterally, although bilateral involvement may occur rarely in severe cases.
- Hemifacial spasm (HFS) generally begins with brief clonic movements of the orbicularis oculi and spreads over years to other facial muscles. Closing of the eye and drawing up of the corner of the mouth are typical.
- Involuntary facial movement is the only symptom.
- Fatigue, anxiety or reading may precipitate the movements. Stressful life events are also associated with HFS.
- Mild facial weakness and contraction appear without frank facial palsy.
- There is normal facial sensation.
- There are no other physical signs.
- Facial myokymia appears as vermicular (worm-like) twitching under the skin:
- Often with a wavelike spread.
- This is distinguished from other abnormal facial movements by characteristic electromyogram.
- Facial myokymia may occur with any pathological brainstem process.
- Most cases are idiopathic and eventually resolve without treatment.
- Myoclonic movements may arise from lesions at the brain or brainstem level.
- They are distinguished from hemifacial spasm (HFS) by the distribution of abnormal movements.
- They tend to be more generalised, possibly bilateral.
- Oromandibular dystonia (OMD) refers to dystonia affecting the muscles of the lower face.
- When OMD occurs with blepharospasm, it is called Meige's syndrome II.
- Henry Meige first described it in 1910.
- Craniofacial tremor may occur in association with essential tremor, Parkinson's disease, thyroid dysfunction or electrolyte disturbance. It occurs rarely in isolation.
- Focal motor seizures must occasionally be distinguished from other facial movement disorders, particularly HFS. Postictal weakness and greater involvement of the lower face are its distinguishing features.
- Facial chorea usually occurs within a systemic movement disorder, eg Huntington's chorea.
- Spontaneous orofacial dyskinesia of the elderly, is observed primarily in the edentulous. It usually responds to proper fitting of dentures.
- Facial tics are brief, repetitive, co-ordinated, semi-purposeful movements of grouped facial and neck muscles:
At initial evaluation, consider hemifacial spasm (HFS) as a symptom, not a diagnosis:
- An abnormal neurological examination (except for the facial movements) should prompt the search for an underlying cause, eg compressive lesion, tumour, stroke.
- Needle electromyogram (EMG) shows irregular, brief, high-frequency bursts (150-400 Hz) of motor unit potentials, which correlate with clinically observed facial movements.
- Magnetic resonance imaging (MRI) is the first-line imaging study.
- Angiography and/or magnetic resonance angiography may be necessary before a vascular surgical procedure.
Medications may be used in early hemifacial spasm (HFS):
- This is when spasms are mild and infrequent or in patients who decline botulinum toxin type A injection. Response to medication varies but can be satisfactory in early or mild cases.
- The most helpful agents are carbamazepine and benzodiazepines, eg baclofen, clonazepam. Topiramate has also been used successfully.
- Often, medication effects attenuate over time, necessitating more aggressive treatment.
- This is a chemical denervation that safely treats most patients, especially those with sustained contractions.
- It works by binding to receptor sites on the motor nerve terminals and, after uptake, inhibits release of acetylcholine, blocking transmission of impulses in neuromuscular tissue.
- The spasms usually relax 3-5 days after injection and the effect lasts approximately 6 months.
- Potential side-effects of botulinum injection are facial asymmetry, ptosis and facial weakness. These are usually transient.
- Most patients are very satisfied with their response to treatment.
- Patients should be warned that although botulinum toxin stops the spasm, the sensation of spasm often persists.
- It is now far more commonly used than surgical intervention.
- This usually consists of exploration of the posterior fossa to separate blood vessels from the VIIth cranial nerve.
- Microvascular decompression of the facial nerve can provide long-term symptom control in approximately 90% of patients with HFS.
- Operative success is improved with EMG use.
- Postoperative complications have been noted in 35% of patients, eg facial palsy, hearing deficit and low cranial nerve palsies. The more immediate and severe the facial palsy was, the more permanent it remained.
- Myectomy is rarely ever required.
Hemifacial spasm (HFS) is a progressive, but nonfatal illness. It usually responds favourably to treatment.
Further reading & references
- Gulevich S, Hemifacial Spasm, Medscape, Jun 2010
- Illingworth RD, Porter DG, Jakubowski J; Hemifacial spasm: a prospective long-term follow up of 83 cases treated by microvascular decompression at two neurosurgical centres in the United Kingdom. J Neurol Neurosurg Psychiatry. 1996 Jan;60(1):72-7.
- Han IB, Chang JH, Chang JW, et al; Unusual causes and presentations of hemifacial spasm. Neurosurgery. 2009 Jul;65(1):130-7; discussion 137.
- Peitersen E; Bell's palsy: the spontaneous course of 2,500 peripheral facial nerve palsies of different etiologies. Acta Otolaryngol Suppl. 2002;(549):4-30.
- Lavon H, Cohen-Kerem R, Uri N; Hemifacial spasm associated with otitis media with effusion: a first reported case. Int J Pediatr Otorhinolaryngol. 2006 May;70(5):947-50. Epub 2005 Nov 15.
- Johnson LN, Lapour RW, Johnson GM, et al; Closely spaced stressful life events precede the onset of benign essential blepharospasm and hemifacial spasm. J Neuroophthalmol. 2007 Dec;27(4):275-80.
- Alonso-Navarro H, Rubio L, Jimenez-Jimenez FJ; Topiramate as treatment for hemifacial spasm. Clin Neuropharmacol. 2007 Sep-Oct;30(5):308-9.
- Jost WH, Kohl A; Botulinum toxin: evidence-based medicine criteria in blepharospasm and hemifacial spasm. J Neurol. 2001 Apr;248 Suppl 1:21-4.
- Costa J, Espfrito-Santo C, Borges A, Ferreira JJ, Coelho M, Moore P, Sampaio C. Botulinum toxin type A therapy for hemifacial spasm. Cochrane Database of Systematic Reviews 2005, Issue 1. Art. No.: CD004899. DOI: 10.1002/14651858.CD004899.pub2.
- Holds JB, White GL Jr, Thiese SM, et al; Facial dystonia, essential blepharospasm and hemifacial spasm. Am Fam Physician. 1991 Jun;43(6):2113-20.
- Moffat DA, Durvasula VS, Stevens King A, et al; Outcome following retrosigmoid microvascular decompression of the facial nerve for hemifacial spasm. J Laryngol Otol. 2005 Oct;119(10):779-83.
- Sekula RF Jr, Bhatia S, Frederickson AM, et al; Utility of intraoperative electromyography in microvascular decompression for Neurosurg Focus. 2009 Oct;27(4):E10.
- Huh R, Han IB, Moon JY, et al; Microvascular decompression for hemifacial spasm: analyses of operative complications in 1582 consecutive patients. Surg Neurol. 2008 Feb;69(2):153-7.
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Dr Hayley Willacy
Dr Hayley Willacy