Benign fasciculation syndrome (BFS) is a disorder characterized by fasciculation (localized, uncoordinated twitching) of various voluntary muscles in the body. The twitching can occur in any voluntary muscle group but is most common in the eyelids, arms, legs, and feet. The twitching may be occasional or may go on nearly continuously. Pain, paraesthesia, generalized fatigue, exercise intolerance and muscle cramping may or may not accompany the twitching.
Though twitching is sometimes a symptom of various serious diseases (spinal injury, muscular dystrophy, ALS, etc), it is much more often due to more benign causes (BFS, over-exertion, etc), and virtually everyone will experience some episodes of benign fasciculation during their lifetime.
In the case of BFS, the cause is unknown, though very frequently anxiety is a major contributing factor. The disorder is not life-threatening and generally not disabling, but it may be persistent enough to create some degree of disability, especially if pain is also present. In many cases, however, the accompanying anxiety is more disabling that the disease itself.
Outlook is mixed. The vast majority of cases clear up spontaneously in a few days or weeks (and in fact are never presented for diagnosis), but some may continue for years. Some degree of control of the fasciculations may be achieved with the same drugs used to treat essential tremor -- beta-blockers and anti-seizure drugs. However, often the most effective approach to treatment is to treat any accompanying anxiety.
