Causes and Treatment of Benign Fasciculation Syndrome

Man holding his calf outside

Jeannot Olivet / E+ / Getty Images

Almost all of us will have experienced a fasciculation at one time or another. A fasciculation is simply a small, involuntary muscle twitch on any part of the body. The twitch can be large enough to be felt but not generally not large enough to cause a muscle jerk.

While some people will notice a fasciculation when it happens—such as when an eyelid twitch—as many as 50% of these events will go unnoticed.

Common Causes of Fasciculation

For the most part, fasciculations are more annoying than serious. In neurological terms, fasciculations are the spontaneous firing of a motor unit, a group of nerve and muscle cells that work together to contract a muscle. With fasciculation, only one or few of these units fire.

Fasciculations can be caused by something as simple as drinking too much caffeine. They may also result from other stimulant and non-stimulant drugs such as:

  • Benadryl (diphenhydramine)
  • Dramamine (dimenhydrinate)
  • Sudafed ( pseudoephedrine)
  • Ritalin (methylphenidate)

At other times, having too little of a certain electrolyte, such as magnesium and calcium, can cause a twitch. The same applies to stress, illness, and even exercise. Exercise is, in fact, one of the more common causes of fasciculation, typically experienced after a person has completed a workout and is at home resting.

None of these should be considered worrisome or in need of urgent attention.

Serious Causes of Fasciculation

Less commonly, fasciculations may be the sign of something more serious. These may include illnesses or conditions that affect the nervous system, either directly or indirectly.

Among them:

  • Amyotrophic lateral sclerosis (also known as Lou Gehrig's disease) and other motor neuron diseases
  • Spinal muscle atrophy, a genetic disorder of the spinal nerves
  • Peripheral nerve damage
  • Spinal injury
  • Paraneoplastic syndrome, a cancer-related nerve disorder
  • Schwartz-Jampel syndrome, a genetic nervous system disorder
  • Moersch-Woltmann syndrome (also referred to as "stiff person syndrome")
  • Rabies

Within this context, the treatment of fasciculation is focused on treating the underlying condition.

Benign Fasciculation Syndrome

In addition to known causes, there is a condition called benign fasciculation syndrome (BFS) characterized by persistent tremors that can often affect a person's quality of life. With BFS, the twitching is often described as being relentless, occurring either continuously or in random episodes.

By definition, BFS is idiopathic, meaning that it has no known cause. Because of this, the diagnosis of BFS needs to be made entirely by exclusion by performing tests and examinations to rule out all other possible causes.The term "benign" is not intended to downplay the disruption BFS can cause to a person's life.

BFS is a chronic disorder and its very persistence can lead to a cascade of symptoms that further diminish a person's ability to function.

These may include:

  • Generalized fatigue
  • Generalized muscle aches
  • Exercise intolerance (inability to exercise to one's expected limit)
  • Globus sensation (the sensation of having something stuck in the throat)
  • Paresthesias (a prickly or burning sensation on parts of the body)
  • Muscle cramping, spasms, or tremors
  • Muscle stiffness
  • Myoclonic jerks (a sudden, involuntary muscle spasm)
  • Hyperreflexia (the sudden onset of high blood pressure)

When accompanied by cramps or pain, the condition is typically referred to as cramp-fasciculation syndrome (CSF).

Treating Benign Fasciculation

While some degree of control may be achieved with the use of beta-blockers and anti-seizure medications, no drug has ever been shown to entirely control the symptoms of BFS.

Managing anxiety has proven to be one of the most effective techniques for managing benign fasciculation syndrome symptoms. Anxiety has both a cause-and-effect relationship with fasciculation: it can both trigger an episode and aggravate its severity once it begins.

If the symptoms of anxiety are severe, it is best to seek help from a trained mental health professional who can assist with anxiety-reduction training or prescribe anti-anxiety drugs. The avoidance of stimulants, including caffeine, is also strongly advised.

Was this page helpful?

Article Sources

  • Simon, N. and Kiernan, M. "Fasciculation anxiety syndrome in clinicians." Journal of Neurology. 2013; 260(7):1743-7. doi:10.1007/s00415-013-6856-8.