Benign, self-limited muscle contractions usually involving the orbicularis oculi muscle in the area of the lower eyelid
There is no exact information on prevalence; usually occurs in young, otherwise healthy people.
Not associated with neurological diseases, provided that there are no other symptoms
Additional investigations are not indicated if myokymia only involves one muscle.
Symptoms and predisposing factors
Fine, continuous involuntary muscle contractions, which progress to involve the entire muscle
An EMG study shows spontaneous, rhythmic or semirhythmic unsynchronised bursts of a single motor unit.
Usually affects the lower eyelid unilaterally, but may occur in other small facial muscles as well.
May occur in other voluntary muscles of the limbs and, more rarely, the trunk.
One episode usually lasts continuously for no longer than a few hours.
Symptoms usually disappear after a few days and do not progress to involve other muscles.
In healthy individuals predisposing factors often include tiredness, stress, physical exertion or excessive caffeine intake.
Alcohol and smoking may also provoke episodes.
Investigations and treatment
No further investigations are indicated, provided that myokymia does not progress to involve other muscles (very rare).
An explanation of the benign nature of the condition and exploration of lifestyle-associated predisposing factors are usually the only treatment needed.
Magnesium is sometimes used as treatment for myokymia, although there is no actual research evidence on its effectiveness.
If the symptoms persist for several months and cause the patient discomfort, botulinum injections may be used.
Symptoms have been known to disappear completely after just one injection, but in some cases repeated treatments may be required.
References
Miller NR. Eyelid myokymia. Surv Ophthalmol 2011;56(3):277-8; author reply 278. [PubMed]