Benign fasciculation syndrome is persistent twitching, tingling, or numbness in one or more muscles.

Benign fasciculation syndrome (BFS) is rare and can be confused with amyotrophic lateral sclerosis (ALS), which is also known as Lou Gehrig’s disease. Because of this possible confusion, it is imperative that doctors perform a thorough diagnosis.

Treatment focuses on managing symptoms and reducing stress levels to help people maintain a high standard of living.

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A fasciculation is commonly known as a muscle twitch. Muscle twitches are normal, and the majority of people will experience one at some point. Typical examples include an eyelid twitch or a leg spasm.

The twitch is usually strong enough for a person to feel. However, it will not cause a sudden jerk or full contraction in the muscle.

Muscles contain motor units, which are a group of muscle and nerve fibers that work together to contract a muscle. When the body needs them to move, they can do so instantaneously.

Fasciculations occur when one or more motor units “fire off” on their own. This activity is out of the brain’s control, and the resulting movement can be unexpected.

People with BFS experience a persistent twitch, tingling, or numbness in one or more of their muscles.

BFS causes chronic muscle twitching, which can last for extended periods of time or come back regularly. Twitches may appear in random muscles and may get better or worse with time.

BFS is rare, and the exact cause is still unknown. One theory is that BFS is a response to a viral infection.

Fasciculations themselves can have a range of causes, including the use of certain substances or medications, especially allergy drugs.

Drugs that may trigger fasciculations include:

These twitches will usually subside when the person stops taking the medication and do not cause BFS.

Muscle twitches may also be due to trauma and injury or may be symptoms of anxiety or depression. They can sometimes be linked to other stress-related symptoms such as irritable bowel syndrome, heartburn, and headache.

Some people who lack certain minerals, such as magnesium or calcium, may also develop muscle twitches.

Fasciculations may also be linked to other routine factors such as:

  • strenuous exercise
  • drinking alcohol
  • smoking cigarettes
  • fatigue
  • caffeine intake

Twitching in the calves and thighs occurs most often. However, it may happen almost anywhere in the body. Fasciculations may appear randomly or may stay in one muscle for an extended period.

The twitch will be most noticeable when the body is at rest. After some time, a person may also experience pain in the affected muscle. The muscle may not respond well to exercise, and many people report feeling weakness as well.

According to an article in the journal Neurology, more than 70 percent of healthy people experience benign fasciculations, which are rarely associated with a serious neuromuscular disorder. These people may also experience numbness and cramps in the affected muscles.

Symptoms of BFS also appear to be a cause of stress and anxiety for people who have the condition.

It is unclear if this stress and anxiety make symptoms worse, though many people report that it does. If stress does exacerbate the symptoms, then some people could find themselves in a cycle of BFS symptoms and anxiety.

Researchers noted that more studies were required to identify what effect treating BFS patients for their anxiety has on their physical symptoms.

Other symptoms can vary, and may include:

  • an inability to exercise
  • itchiness or shakiness in the muscles
  • sudden quick, jerking contractions or involuntary muscle spasms
  • stiffness
  • general fatigue
  • symptoms of anxiety, such as a lump in the throat, a headache, or shortness of breath

When diagnosing BFS, doctors will look for a variety of different things. They will test a person’s tendon reflexes and ask about their medical history, personal background, and stress levels. The doctor will usually also carry out strength and resistance tests.

Much of the diagnosis focuses on ruling out other more serious disorders, such as multiple sclerosis (MS) or ALS.

If a doctor thinks a person may have a more serious condition, they may also do neurological testing, blood work, and electromyography to rule out nerve damage. BFS is not associated with nerve damage, so finding any nerve damage would be a sign of a different disorder.

Doctors may prescribe medications to treat tremors or cramps. Some anti-inflammatory drugs or muscle relaxers may help people with pain, fatigue, and inflammation. If blood work identifies any mineral deficiency, the person may use supplements.

Because of the strong link that BFS has to stress and anxiety, it is important for people diagnosed with the condition to try to reduce their daily stress and anxiety.

A person can help reduce anxiety by:

  • meditating, practicing yoga, or listening to calming music
  • spending time with a pet, which has been shown to reduce stress, fear, and anxiety
  • eating a balanced diet rich in whole foods and nutrients
  • eating probiotics, which can be found in foods such as sauerkraut, kimchi, yogurt, miso, and kefir

Benign fasciculations may be challenging to treat. However, many people find they can manage their symptoms with lifestyle changes.

If symptoms persist, get worse, or interfere with a person’s quality of life, they should see a doctor to discuss treatment options.

BFS and ALS may display some similar symptoms. However, they are different disorders.

A key sign of ALS is what is known as muscle wasting. The affected muscles will atrophy or get smaller over time. This also means that a person with ALS will begin to feel weaker as the condition progresses. Muscle wasting does not usually occur with BFS.

While both conditions create muscle fasciculations, fasciculations appear to be more widespread in BFS. The twitching also affects the muscle while it is resting. However, it will stop when the person starts using the muscle.

In ALS, twitching can start in one place. However, it will often spread to the areas near that starting point rather than appearing in random places.

Many people with BFS fear that it can turn into ALS. However, the two disorders are different and do not seem to have any significant link to each other.

Anyone who is uncertain of their symptoms should return to their doctor for a diagnosis.

BFS has no known cause or permanent treatment, and symptoms can disrupt everyday life. There are some lifestyle changes that can help make a difference in some people.

If a person is experiencing persistent muscle twitches and has not yet been diagnosed, they should speak with a doctor. The doctor may need to rule out any other possible causes or underlying conditions.

By working directly with a doctor to diagnose BFS and develop a treatment plan, many people find they can manage their symptoms well.