Myokymia

What it means

Myokymia consists of involuntary, fine, continuous, undulating contractions that spread across the affected striated muscle.

Myokymia is characterized electrophysiologically by rhythmic or semi-rhythmic bursts of a single motor unit discharging several times a second at a rate of 3-8 Hz. These myokymic discharges are nonsynchronous in different muscles or even in the same muscle, with intervals of 100-200 milliseconds separating individual bursts. The spontaneous discharges are not initiated by voluntary movement, although they may increase with such activity.

Rare diseases that can present with this8

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category