Muscle Twitches and Multiple Sclerosis

This symptom is relatively common, but it's usually unrelated to MS.

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Occasional muscle twitches are very common and rarely signal the presence of an underlying disease if they occur without other symptoms. However, if you have multiple sclerosis and experience muscle twitches—also known as fasciculations—you might wonder whether they're a symptom of your condition.

Fasciculations are rarely a symptom of MS. When they do occur, MS-related muscle twitches typically develop only in association with a flare-up or advanced disease.

If neither of these circumstances apply and you experience muscle twitching, it might represent a normal response to something like too much caffeine or not getting enough sleep.

Muscle Twitches in MS

Muscle twitching occurs when nerves misfire, causing groups of muscle fibers to contract. This occurs occasionally in most healthy people, representing nothing more than a momentary glitch. Frequent or widespread fasciculations, however, can occur with a variety of medical conditions.

Muscle twitching is a hallmark symptom of diseases that affect the lower motor neurons—nerve cells originating in the spinal cord that are involved in voluntary muscle movement. Amyotrophic lateral sclerosis, better known as ALS or Lou Gehrig disease, is an example of such a disease. Destruction of lower motor neurons in ALS causes fasciculations, a characteristic feature of the disease.

Multiple sclerosis rarely involves the lower motor neurons, which is why fasciculations are usually not a symptom of the disease.

However, people with advanced MS sometimes have lower motor neuron involvement, which can lead to muscle twitching—although this is rare.

Other Causes of Twitching Muscles

Most muscle twitches are benign and transient, meaning they are not a serious health concern, and come and go quickly. Fasciculations that are unrelated to an underlying disease or abnormality can be triggered by a number of things, including:

  • Strenuous exercise
  • Tiredness or lack of sleep
  • Too much caffeine or alcohol
  • Exposure to extreme cold
  • Hyperventilation
  • Stress or anxiety
  • Certain medications, such as water pills or steroid medicines

Two uncommon conditions called benign fasciculation syndrome and cramp fasciculation syndrome cause frequent muscle twitches and, in the latter syndrome, muscle cramps. These conditions are believed to be due to hyperexcitable nerves and are not associated with loss or nerve or muscle function.

Muscle twitching may also be a symptom of certain diseases and conditions outside the nervous system, such as:

  • an overactive thyroid gland
  • an overactive or underactive parathyroid gland
  • severe kidney disease
  • nutritional deficiencies, such as vitamin D, vitamin B12, magnesium, and potassium

Next Steps

It's always disconcerting to develop a new or unexplained symptom when you're living with MS. If you experience frequent or troublesome muscle twitches, see your doctor. There may be a simple explanation and relatively easy intervention to control this symptom. If no cause can be identified, at least you'll have the reassurance of knowing it's not something you need to worry about.


Leite MAA, Orsini M, de Freitas MRG, et al. Another Perspective on Fasciculations: When Is It Not Caused by the Classic Form of Amyotrophic Lateral Sclerosis or Progressive Spinal Atrophy? Neurology International. 2014;6(3):5208. doi:10.4081/ni.2014.5208.

Loma I, Heyman R. Multiple Sclerosis: Pathogenesis and TreatmentCurr Neuropharmacol. 2011 Sep; 9(3):409–416.

Motor Neuron Diseases Fact Sheet. National Institute of Neurological Diseases and Stroke website.

Multiple Sclerosis. Cleveland Clinic Center for Continuing Education website.

Younger DS. Motor Disorders. Brookfield, CT: Rothstein Publishing; 2015.

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