(HealthDay News) -- Muscle twitches, especially involving the eyelids, calf or thumb -- are fairly common.
Rarely, they can be a sign of a nervous system disorder, the U.S. National Library of Medicine says. Signals of a serious muscle problem include a change in muscle sensation, size, and a feeling of muscle weakness.
On the other hand, most muscle twitches aren't anything to worry about and only last for a few days or less. The NLM offers this list of common causes:
Having a dietary deficiency.
Getting too much caffeine.
Taking certain medications, such as steroids, estrogen hormones or diuretics.
Having anxiety or stress.