Muscle spasms (SPAH-zumz) and cramps occur when a muscle involuntarily contracts (tightens) and does not relax. Spasms and cramps can occur in part, or all, of one or more muscles. A muscle spasm or cramp is often called a charley horse.
Muscle spasms and cramps are sudden, persistent contractions. They can occur in any muscle in the body but most often occur in the legs. The most common muscle groups affected by spasms and cramps include:
Muscle spasms and cramps are often caused by muscle overuse or injury. Spasms or cramps in the calf can occur while running or while kicking when swimming. Spasms or cramps in thigh muscles are more common during running or jumping. Spasms and cramps can occur while playing tennis or golf, bowling, or performing any other exercise. They also can occur at night in bed. They can be caused by dehydration * , especially when exercising without drinking adequate fluids, or by low levels of electrolytes * (minerals), such as calcium or potassium.
Some muscle spasms are caused by irritation of a nerve connected to a muscle. For example, painful spasms in back muscles can occur when a herniated disk * in the spine irritates spinal nerves. Spasms in the cervical spine of the neck may be caused by stress.
Muscle spasms and cramps also can be caused by:
Muscle spasms and cramps are a common type of myopathy * and are not usually serious. However, muscle spasms and cramps are also symptoms of more serious myopathies—neuromuscular disorders that are usually characterized by muscle weakness caused by dysfunction of muscle fiber. Myopathies that may cause muscle spasms and cramps include:
Muscle spasms and cramps are very common. Most people have spasms and cramps at least occasionally or under certain circumstances.
When a muscle spasms or cramps, it feels very tight. It may bulge or feel hard or knotted. Spasms and cramps can be very painful. They are different from muscle twitching, which is caused by minor muscle contractions or uncontrollable twitching of a muscle group that is served by a single motor nerve fiber.
The doctor will ask about symptoms, take a medical history, and perform an examination to check for muscles that are tight, hard, or very tender. Patients will be asked about the affected muscles, whether the spasms and cramps are always in the same location, when they first began, how often they occur, and how long the spasms and cramps usually last. The doctor also will ask about additional symptoms, such as vomiting, diarrhea, excessive sweating, excessive urination, or any other possible symptoms or causes of dehydration. Patients will be asked about all of the medications and supplements that they take, about exercise routines, and about alcohol use. Blood tests may be performed to check the levels of calcium, potassium, and magnesium and to check kidney and thyroid function. Magnetic resonance imaging * (MRI) may help diagnose problems, such as back spasms, that are caused by nerve irritation.
Muscle spasms and cramps are treated by immediately stopping any activity and stretching and massaging the affected muscle. Drinking water or a sports drink can help relieve cramps caused by dehydration, and sports drinks or salt tablets can help replace lost electrolytes. Initially, heat is used to relax the muscle; once the pain has lessened, ice can be helpful. If the muscle is still sore following heat and ice treatments, nonsteroidal anti-inflammatory drugs * (NSAIDs), such as ibuprofen or naproxen, can relieve the pain. Severe cases may be treated with prescription antispasmodic medications or muscle relaxants, as well as prescription pain medications.
The underlying cause of frequent or persistent muscle spasms and cramps may require additional treatment. An irritated nerve may require physical therapy or even surgery. Some myopathies are treated with drugs, such as medications to suppress the immune system, or bracing to support weakened muscles, as well as physical therapy and/or surgery. However, for some myopathies, only supportive treatment or treatment for specific symptoms is necessary or available.
Muscle spasms and cramps almost always eventually dissipate with rest. However, a doctor should be contacted if muscle spasms and cramps:
Muscle spasms and cramps that regularly occur while exercising or playing sports can usually be prevented by drinking adequate fluids and increasing potassium intake. Bananas and orange juice are excellent sources of potassium. Stretching can improve flexibility and help prevent spasms and cramps. Exercising properly with the appropriate training is also important for preventing recurrent muscle spasms and cramps. Prevention may involve modifying an exercise program to ensure that it is within an individual's physical abilities.
See also Fluid and Electrolyte Disorders
MedlinePlus. “Charley Horse.” U.S. National Library of Medicine, National Institutes of Health. https://www.nlm.nih.gov/medlineplus/ency/article/002066.htm (accessed April 15, 2016).
MedlinePlus. “Muscle Cramps.” U.S. National Library of Medicine, National Institutes of Health. https://www.nlm.nih.gov/medlineplus/ency/article/003193.htm (accessed April 15, 2016).
National Institute of Neurological Disorders and Stroke. NIH Neurological Institute, PO Box 5801, Bethesda, MD 20824. Telephone: 301-496-5751. Toll-free: 800-352-9424. Website: http://www.ninds.nih.gov (accessed April 15, 2016).
* hamstrings are the three muscles at the back of the thigh that flex and rotate the leg and extend the thigh.
* quadriceps (KWAH-dri-seps) are the four-parted large extensor muscles of the front of the thighs that join in a single tendon at the knee.
* dehydration (dee-hi-DRAY-shun) is a condition in which the body is depleted of water, usually due to excessive loss of body fluids, such as through sweating, vomiting, or diarrhea.
* electrolytes (ee-LEK-troh-lites) are ions such as sodium, potassium, or calcium that are dissolved in bodily fluids including the blood and that regulate or affect most metabolic processes.
* herniated disk (HER-nee-ay-ted disk) is a blister-like bulging or protrusion of the contents of an intervertebral disk; also called a prolapsed, slipped, displaced, or ruptured disk.
* myopathy (MI-ah-path-ee) is any disorder that causes muscle weakening, often accompanied by muscle spasms or cramps.
* tetany (TE-tan-ee) is a nervous system disorder characterized by muscle cramps, spasms, and numbness in the arms and legs.
* magnetic resonance imaging (MRI) uses magnetic waves, instead of x-rays, to scan the body and produce detailed pictures of the body's structures.
* nonsteroidal anti-inflammatory drugs (NSAIDs) are over-thecounter and prescription medications, such as naproxen sodium and ibuprofen, for reducing pain and inflammation.