What is a muscle spasm?
A muscle spasm, or muscle cramp, is an involuntary contraction of a muscle. Muscle spasms occur suddenly, usually resolve quickly, and are often painful.
A muscle spasm is different than a muscle twitch. A muscle twitch, or fasciculation, is an uncontrolled fine movement of a small segment of a larger muscle that can be seen under the skin.
Muscle Spasm facts
- Spasms can affect many different types of muscles in the body, leading to many different symptoms.
- Spasms of skeletal muscles are most common and are often due to overuse and muscle fatigue, dehydration, and electrolyte abnormalities. The spasm occurs abruptly, is painful, and is usually short-lived. It may be relieved by gently stretching the muscle.
- If muscle spasms are especially painful, if they do not resolve or if they recur, medical care should be accessed to look for other possible underlying causes.
- Smooth muscles that are within the walls of hollow organs (like the colon) can go into spasm, causing significant pain. Often this pain is colicky, meaning that it comes and goes. Examples include the pain associated with menstrual cramps, diarrhea, gallbladder pain, and passing a kidney stone.
- A special form of muscle spasms are the dystonias where an abnormality perhaps exists with the chemicals that help transmit signals within the brain. Examples include torticollis and blepharospasm. Treatment may include medications to help restore the neurotransmitter levels to normal and Botox injections to paralyze the affected muscle and relieve the spasm.
What are common causes of muscle spasms?
There are a variety of causes of muscle spasms, and each depends upon predisposing factors, the part of the body involved, and the environment that the body is in.
Spasms may occur when a muscle is overused, tired, previously injured, or strained. The spasm may occur if the muscle has been overstretched or if it has been held in the same position for a prolonged period of time. In effect, the muscle cell runs out of energy and fluid and becomes hyperexcitable, resulting in a forceful contraction. This spasm may involve part of a muscle, the whole muscle, or even adjacent muscles.
- Overuse as a cause of skeletal muscle spasm is often seen in athletes who are doing strenuous exercise in a hot environment. This is also an occupational issue with construction workers or others working in a hot environment. Usually, the spasms will occur in the large muscles that are strained, being asked to do the work. When this occurs associated with heat exposure, the condition is also known as heat cramps.
Overuse can also occur with routine daily activities like shoveling snow, or mowing or raking grass, causing muscle spasms of the neck, shoulder, and back.
- Unfamiliar exercise activities can also cause muscle spasms to occur. Abdominal spasms can occur when a person decides to begin working their abdominal muscles by doing sit-ups and repeating too many too quickly.
- Writer’s cramps of the hand and fingers are similarly caused by prolonged use of the small muscles in the hand and the overused muscles cramp. People will routinely rest and stretch their fingers either to prevent or treat this situation.
- It is commonly thought that dehydration and depletion of electrolytes will lead to muscle spasm and cramping. Muscle cells require enough water, glucose, sodium, potassium, calcium, and magnesium to allow the proteins within them to develop an organized contraction. Abnormal supply of these elements can cause the muscle to become irritable and develop spasm.
- Atherosclerosis or narrowing of the arteries (peripheral artery disease) may also lead to muscle spasm and cramps, again because an inadequate blood supply and nutrients are delivered to the muscle. Peripheral artery disease can decrease the flow of blood to the legs, causing pain in the legs with activity. There may also be associated muscle cramps.
- Leg spasms are often seen related to exercise, but cramps may also be seen at night involving calf and toe muscles. Nocturnal leg cramps and restless legs syndrome are considered a type of sleep disturbance. Their prevalence increases with age and often a precise cause is not found.
- Chronic neck and back pain can lead to recurrent muscles spasms. Large muscle groups make up the trunk, including the neck, chest wall, upper back, lower back, arms, and legs. Spasms in these muscles can be a result of an injury or they may develop over time because of arthritic changes in the spine. Obesity can cause stress and strain of the core muscles of the trunk, resulting in muscle cramps of the neck and upper and lower back. Systemic illnesses like diabetes, anemia (low red blood cell count), kidney disease, and thyroid and other hormone issues are also potential causes of muscle spasms.
- Diseases of the nervous system, such as amyotrophic lateral sclerosis, multiple sclerosis, or spinal cord injury, can be associated with muscle spasm.
- Smooth muscle can also go into spasm. When a hollow structure filled with air or fluid is squeezed by the muscle spasm, significant pain may occur, since the fluid or air cannot be compressed. For example, smooth muscle in the intestinal wall can go into spasm, causing waves of pain called colic. Colicky pain which tends to come and go may also occur within the bile duct that empties the gallbladder and may develop after eating.
- When kidney stones try to pass through the urinary tract, the smooth muscles that are in the walls of the ureter (that connects the kidney to the bladder) may spasm rhythmically and cause significant pain. Often this type of pain is associated with nausea and vomiting and is called renal colic.
- Muscles that surround the esophagus can go into spasm when acid reflux causes irritation of the lining of the esophagus, resulting in esophagitis or GERD (gastroesophageal reflux disease).
- Diarrhea can be associated with colicky pain, where the muscles within the colon wall spasm just before a watery bowel movement.
- Menstrual cramps occur when the walls of the uterus contract forcefully.
- The coronary arteries that supply the heart muscle with blood also have smooth muscle within their walls that may go into spasm. This can cause chest pain that may be indistinguishable from the pain of coronary artery disease (where plaque has accumulated and narrowed the arteries). Coronary artery spasm often occurs in smokers or those who have high cholesterol blood levels. Coronary artery spasm may be triggered by stress, alcohol withdrawal, stimulant drug abuse (especially cocaine) or medications that can constrict or narrow blood vessels. Coronary artery spasm is also known as Prinzmetal’s angina.
- Dystonias are movement disorders where groups of muscles forcefully contract and cause twisting. Uncontrolled repetitive movements and the inability to maintain normal posture may be the result of this type of muscle spasm and cramping. The symptoms may be very mild initially but gradually progress to become more frequent and aggressive. Occasionally, there is no progression. Examples of this type of muscle spasm include torticollis (where the neck muscles spasm and cause the head to turn to one side), blepharospasm (where there is uncontrolled blinking of the eyes), and laryngeal dystonia that affects the muscles that control speech. Dystonias may be caused by abnormally functioning neurotransmitter chemicals within part of the brain called the basal ganglia. These chemicals (serotonin, dopamine, acetylcholine, and GABA) are required to properly send messages between brain cells that begin muscle contraction. Dystonia symptoms may occur as a complication of stroke.
What are risk factors for muscle spasms?
Most people are at risk for developing a muscle spasm at one time in their life, from infant colic to kidney stones. The risks differ depending upon the person’s past medical history, their occupation, and level of physical activity. Examples include the following:
- Construction and factory workers who work in hot environments are at risk for becoming dehydrated and developing heat cramps. This same situation can occur in athletes, both elite and recreational.
- Patients with peripheral artery disease can develop leg cramps at night. Risk factors are the same as for stroke and heart attack: high blood pressure, high cholesterol, diabetes, and smoking.
- Patients who have underlying neurologic disorders are at risk for developing muscle spasms.