Muscles are made up of fibers that your nerves control. Muscle twitching is caused by minor muscle contraction in the area, or uncontrollable twitching of a muscle group that is served by a single motor nerve fiber. Stimulation or damage to a nerve may cause your muscle fibers to twitch. Most muscle twitches are minor and aren’t usually a cause for concern. Some are common and normal. Others are signs of a nervous system disorder.
These may include:
- Autoimmune disorders such as Isaac syndrome.
- Drug overdose (caffeine, amphetamines, or other stimulants).
- Lack of sleep.
- Drug side effect (such as from diuretics, corticosteroids, or estrogens).
- Exercise (twitching is seen after exercise).
- Lack of nutrients in the diet (deficiency).
- Medical conditions that cause metabolic disorders, including low potassium, and kidney disease, and uremia.
- Twitches not caused by disease or disorders (benign twitches), often affecting the eyelids, calf, or thumb. These twitches are normal and quite common, and are often triggered by stress or anxiety . These twitches can come and go, and usually do not last for more than a few days.
Nervous system conditions that can cause muscle twitching include:
- Amyotrophic lateral sclerosis (Lou Gehrig disease)
- Neuropathy or damage to the nerve that leads to a muscle
- Spinal muscular atrophy
- Weak muscles (myopathy)
When to Contact a Medical Professional
Call your health care provider if you have long-term or persistent muscle twitches or if twitching occurs with weakness or loss of muscle.