Muscle twitching is the presence of uncontrollable muscle contractions that can be temporary or chronic. When this occurs in the thumb, it can be called thumb twitching, and it can occur for a variety of reasons, including overuse of the muscle from playing video games or texting, nutritional deficiencies, carpal tunnel syndrome, or restricted blood flow. Other causes may include neurological disorders, prescription drug side effects, anxiety, or a chronic state of tension. Muscle twitching is very common and most cases of thumb twitching are benign, but continued twitching indicates a serious condition.
Repetitive motion injury is a very common cause of thumb twitches. Video game modules and remote controls, cell phones, and other electronic devices require constant, unnatural use of the thumb, which irritates the nerves that control the thumb muscles. The thumb may exhibit uncomfortable muscle contractions, tingling, burning, or tendinitis from constant stress.
Carpal tunnel syndrome, a type of nerve trauma in which the median nerve is inappropriately compressed, can cause thumb twitching, but is usually associated with wrist pain or burning of the wrist joint. Repetitive motion injury and carpal tunnel syndrome usually improve when the offending actions cease, although carpal tunnel syndrome can have underlying causes ranging from genetic factors to more serious physiological factors such as fibroids.
Thumb twitching can be caused by an electrolyte imbalance from nutritional deficiencies in the diet. A deficiency of calcium or magnesium has been shown to cause muscle spasms and cramps throughout the body, even in the thumbs. Medication side effects can also cause spasms in the fingers and thumbs. Drugs like corticosteroids, estrogens, diuretics, and caffeine stimulate the muscles, which could lead to spasms. Extreme anxiety releases hormones that upset the balance of the nervous system, causing muscle spasms that can include the thumbs.
Chronic thumb twitching with a gradual loss of muscle coordination is often a sign of more serious neurological disorders. Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, is a progressive and debilitating nerve disease. ALS symptoms usually begin with muscle spasms in the chest and rib area, progressing down the arm, sometimes affecting the thumb. Multiple sclerosis and Parkinson's syndrome also affect the nerves that control muscles, including the thumb. Although many cases of thumb twitching are benign and caused by environmental factors, continued twitching that becomes increasingly severe requires a medical diagnosis to determine the underlying cause.