What does it mean if your body twitches

Q: Many people who have muscle twitching worry that they have ALS since it’s often associated with the disease. If a person has muscle twitches a lot, or even daily, could it be the beginning of ALS?

A: Muscle twitching is very common, especially when people have had too much coffee, too much stress, or not enough sleep.  Does this sound familiar?  

Of course, the first thing many people do when they have a symptom is to run to the computer to see what Dr. Google has to say about it.  I just did that and I got 1,390,000 results in 0.25 seconds.  One of the first items that popped up was a Wikipedia definition leading to the term "fasciculations," (which means muscle twitching), suggesting the symptoms could be associated with ALS. And then of course it’s natural to panic.  So if you were not under stress at the start before you went to the Internet, you certainly would be after consulting Dr. Google.

But take a breath.  There are many things that can cause muscle twitching, including fatigue, anxiety, or even a pinched nerve in the spine. Muscle cramps, too, are very common, and can be caused by such things as over-exertion or even dehydration. Just watch any basketball game: it seems there’s always somebody on the floor dealing with a significant leg cramp.

Symptoms such as muscle twitching and muscle cramps don’t tell you much just by themselves; they are very common and non-specific.  To diagnosis ALS, a physician needs to see signs of progressive muscle weakness. 

What causes fasciculations? They originate at the very tips of the nerves, called axons, as they come close to being in contact with the muscle. The tips of the axons are thought to be overly sensitive to depolarizing (electrical firing), which is what triggers a muscle to contract.  When a nerve fires, zillions of times a day upon request, an electrical impulse starts in the nerve, moves out toward the muscle, triggers the release of a chemical (acetylcholine) that "swims" across the gap between the nerve axon and the muscle, and binds to a receptor on the muscle causing it to fire. The complicated process itself takes a small fraction of a second.  If any of this happens involuntarily, then the muscle fiber contracts without your permission and behold, a muscle twitch or fasciculation!

Some people with ALS wonder if the presence of muscle twitching means they have a bad or fast-moving version of the disease. In fact, having fasciculations doesn't correlate with how rapidly the disease progresses.

I would suggest most people with fasciculations or muscle cramps wait a few months although there’s no hard and fast rule -- before seeking a medical evaluation.  Often the twitching or cramping will just stop on its own. If it doesn’t, it makes sense to get your problem evaluated. 

An internist or a neurologist will ask you some questions, learn more about what you’ve been experiencing, and hold your limb in a relaxed position and study the twitching. He or she may then want you to have a muscle test (an EMG) to better understand what could be going on.  Blood tests might be needed as well.

Often, the results will look normal but the doctor may suggest waiting a little longer to see if anything further develops over the next few months.  Even in the 21st century, there is sometimes no instant test or procedure that can give you a clear answer about a problem. With fasciculations, this is certainly the case. 

Waiting is a challenge for most people, but the odds are heavily in your favor that you don't have ALS.  As they say, "common things are common," and ALS is not common, especially when compared to excessive caffeine use and stress. 

Edward Kasarskis, M.D., Ph.D. is Director of the multidisciplinary ALS Center at the University of Kentucky Neuroscience Center in Lexington, Kentucky, professor in the Department of Neurology at the University of Kentucky, and Chief of Neurology at the VA Medical Center in Lexington KY. 

Muscle twitches are fine movements of a small area of muscle.

Muscle twitching is caused by minor muscle contractions in the area, or uncontrollable twitching of a muscle group that is served by a single motor nerve fiber.

Muscle twitches are minor and often go unnoticed. Some are common and normal. Others are signs of a nervous system disorder.

Causes 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).
• Stress.
• Medical conditions that cause metabolic disorders, including low potassium, 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 (ALS), also sometimes called Lou Gehrig disease or motor neuron disease
• Neuropathy or damage to the nerve that leads to a muscle
• Spinal muscular atrophy
• Weak muscles (myopathy)

Symptoms of a nervous system disorder include:

• Loss of, or change in, sensation
• Loss of muscle size (wasting)
• Weakness

No treatment is needed for benign muscle twitching in most cases. In other cases, treating an underlying medical cause may improve symptoms.

Contact your health care provider if you have long-term or persistent muscle twitches or if twitching occurs with weakness or loss of muscle.

Your provider will take a medical history and perform a physical exam.

Medical history questions may include:

• When did you first notice the twitching?
• How long does it last?
• How often do you experience twitching?
• What muscles are affected?
• Is it always in the same location?
• Are you pregnant?
• What other symptoms do you have?

Tests depend on the suspected cause, and may include:

• Blood tests to look for problems with electrolytes, thyroid gland function, and blood chemistry
• CT scan of the spine or brain
• Electromyogram (EMG)
• Nerve conduction studies
• MRI scan of the spine or brain

Muscle fasciculation; Fasciculations of muscle

Deluca GC, Griggs RC. Approach to the patient with neurologic disease. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 368.

Hall JE, Hall ME. Contraction of skeletal muscle. In: Hall JE, Hall ME, eds. Guyton and Hall Textbook of Medical Physiology. 14th ed. Philadelphia, PA: Elsevier; 2021:chap 6.

Weissenborn K, Lockwood AH. Toxic and metabolic encephalopathies. In: Jankovic J, Mazziotta JC, Pomeroy SL, Newman NJ, eds. Bradley and Daroff's Neurology in Clinical Practice. 8th ed. Philadelphia, PA: Elsevier; 2022:chap 84.

Updated by: Joseph V. Campellone, MD, Department of Neurology, Cooper Medical School at Rowan University, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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