What is the best approach to treating a patient with facial myokymia?

Facial Myokymia Treatment

For facial myokymia, immediately investigate for underlying brainstem pathology—particularly multiple sclerosis or brainstem tumors—and if persistent and troublesome after addressing the underlying cause, treat with botulinum toxin type A injections, which have demonstrated effectiveness and safety in eliminating continuous hemifacial myokymia. 1

Initial Diagnostic Approach

Facial myokymia is an involuntary undulating, vermicular movement beneath the skin supplied by the facial nerve, and it almost always indicates intrinsic brainstem pathology rather than a peripheral nerve disorder. 2, 1

Critical diagnostic steps:

• Obtain brain MRI with focus on the pons to identify demyelinating lesions (particularly T2/FLAIR hyperintensities near the postgenu course of the facial nerve), brainstem tumors, or posterior fossa masses. 2, 3
• Consider multiple sclerosis as the primary diagnosis in patients under age 40, as MS accounts for approximately 42% of facial myokymia cases (18 of 43 patients in the largest case series). 3
• Evaluate for brainstem tumors or posterior fossa tumors, which account for approximately 14% of cases (6 of 43 patients). 3
• Rule out obstructive communicating hydrocephalus, which can rarely present with facial myokymia as a false localizing sign. 4
• Perform electromyography to confirm the characteristic pattern of myokymia and differentiate from other movement disorders like hemifacial spasm or myoclonus. 1, 3

Treatment Algorithm

Step 1: Address the Underlying Cause

• For multiple sclerosis: The facial myokymia typically resolves spontaneously within weeks to months as the demyelinating lesion improves, though it may persist for extended periods. 2, 1, 3
• For brainstem tumors: Surgical resection or appropriate oncologic management is the definitive treatment. 3
• For obstructive hydrocephalus: Ventriculoatrial or ventriculoperitoneal shunt placement results in resolution of facial myokymia. 4

Step 2: Symptomatic Treatment for Persistent Cases

When facial myokymia persists beyond 1 month and is troublesome to the patient, inject botulinum toxin type A into the affected facial muscles. 1

• Botulinum toxin A has successfully eliminated continuous hemifacial myokymia in MS patients with symptoms persisting up to 1 month. 1
• This represents the only documented effective symptomatic treatment for persistent facial myokymia. 1
• The treatment is safe and well-tolerated in this population. 1

Important Clinical Distinctions

Do not confuse facial myokymia with Bell's palsy or hemifacial spasm:

• Facial myokymia presents as continuous undulating movements, not facial weakness or intermittent spasms. 2, 1
• Unlike Bell's palsy, facial myokymia indicates central (brainstem) pathology, not peripheral facial nerve dysfunction. 2
• The electromyographic pattern of myokymia is distinct from other facial movement disorders. 1, 3

Critical Pitfalls to Avoid

• Never dismiss facial myokymia as benign fasciculations—it mandates neuroimaging to exclude serious brainstem pathology. 2, 3
• Do not delay MRI imaging in patients presenting with facial myokymia, as early detection of MS or brainstem tumors significantly impacts prognosis. 2, 3
• Recognize that facial myokymia may evolve in severity over the course of the underlying illness, particularly in multiple system atrophy where it may be initially subtle. 5
• Understand that facial myokymia can persist for years (up to 13 years documented) and may recur, requiring long-term monitoring. 3