WHAT CAUSES MUSCLE SPASM?

Spasms may affect many different types of muscles in the body, leading to many different symptoms and presentations. Spasms of skeletal muscles are most common and are often due to 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 possible underlying causes.

Smooth muscles that are within the walls of hollow organs 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.

Muscles are complex structures that cause movement in the body. There are three types of muscle in the body:

▪ Heart muscle pumps blood (cardiac muscle).
▪ Skeletal muscle moves the external body parts, like the arms and legs, neck, back, trunk, and the face.
▪ Smooth muscle moves portions of hollow structures inside the body.

Examples include the muscles that line the esophagus, stomach, and intestines, muscles that line large arteries, and the muscles of the uterus

Skeletal muscles are anchored to bone, either directly or by a tendon. When the muscle contracts, the associated body part moves. This allows arms to lift, legs to run, and the face to smile. Most of these muscles are under willful or conscious control of the brain. The contraction of a skeletal muscle requires numerous steps within its fibers and cells. The nutrients required producing energy, oxygen, electrolytes, and glucose are supplied by the bloodstream.

Smooth muscle is located in the walls of hollow internal structures in the body, like the arteries, intestines, bladder, and iris of the eye. They tend to circle the structure and when they contract, the hollow structure is squeezed. These muscles are involuntary and are controlled by the unconscious part of our brain function using the autonomic nervous system.

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 and tired, particularly if it is 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 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 does too many too quickly. Writers cramps of the hand and fingers are similarly caused by prolonged use of the small muscles in the hand.

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, and lower back. Spasms in these muscles can be a result of an injury or they may develop over time because of arthritic changes in the spine. 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 irritation occurs with reflux esophagitis or GERD.

▪ 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.

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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 or medications that can constrict or narrow blood vessels. Coronary artery spasm is also known as Prinzmetals 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 becomemore 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

The symptoms of muscle spasm depend upon the muscle involved and the circumstances leading up to the spasm. Skeletal muscle spasm usually involves muscles that are being asked to do excessive work. There is acute onset of pain as the muscle contracts. A bulging, tight muscle may be seen or felt underneath the skin where the muscle is located. Most often, the spasm resolves spontaneously after a few seconds though it may last many minutes or longer. Usually, those affected will feel the need to stretch the muscle involved, thus relieving the spasm and resolving the episode. With heat cramps, the muscle spasm may occur after the activity is completed.

A muscle fasciculation or twitch may last just a few seconds or may be a recurrent event. Usually, its just a momentary repetitive contraction of just a few muscle fibers of a larger muscle in a localized area served by one nerve fiber. This often involves the eyelid, calf, thigh, or thumb. The fasciculations often come and go and may be related to stress or anxiety. Ingestion of stimulants like caffeine and pseudoephedrine found in over-the- counter cold medications may also cause the twitch. Medications such as albuterol (Ventolin, Proventil, AccuNeb, VoSpire, ProAir) used for the treatment of asthma and medications used to treat attention deficit disorder (Adderall) may be associated with twitching. These twitches are considered harmless and are referred to as benign fasciculations.

However, muscle twitching may also be associated with neurologic disorders such as muscular dystrophy, amyotrophic lateral sclerosis, and myopathy (a primary muscle illness). With these diseases, associated symptoms include weakness, muscle wasting with loss of muscle size, and change in sensation.

Smooth muscle spasm will cause colicky pain that comes and goes. The symptoms will depend upon the organ involved Most people have experienced a skeletal muscle spasm due to overexertion, especially in a warm environment, and are able to self-diagnose. However, if the spasms are severe, last a long time, or keep recurring, it is reasonable to see a health-care professional for evaluation.

The diagnosis usually begins with history and physical examination. It is helpful to know the circumstances surrounding the muscle spasms.

▪ When did they begin? How long do they last? How frequently do they occur? Are they rhythmic or more random? Is it always the same muscle group of the body involved?

▪ Other information that is helpful includes whether there have been any recent illnesses or whether any medications have been taken, including prescription medications, over-the- counter medications, food supplements, and herbal remedies.

▪ Past medical history may give a clue as to the reason for the muscle cramps. These may include a history of diabetes, hypothyroidism, kidney disease, and spinal cord injury.

▪ Work or exercise history may be of importance.

Sometimes the physical examination may be normal since the muscle spasms may not be present during the visit. However, the physical examination may useful in detecting underlying medical issues that may be helpful in making the diagnosis. For example, if the patient is complaining of leg muscle spasm, the examination may include palpating or feeling for pulses in the feet. Atherosclerosis, or hardening of the arteries, may be associated with the loss of arterial pulse in the involved extremity.

For those having pain from smooth muscle spasm, the pain may be severe enough to present to an emergency department. The history and physical examination will be directed to finding the source of the pain, while at the same time trying to control the symptoms. Kidney stone pain (renal colic) and gall bladder pain sometimes require anti-inflammatory or narcotic pain medication. They are often associated with nausea and vomiting and these symptoms may also require treatment. Some patients with irritable bowel condition may also present with significant intestinal spasm and abdominal pain.

For patients with recurrent muscle spasm where the cause is not easily diagnosed by history and physical examination, testing may be necessary to give direction as to potential causes. Blood tests may or may not be indicated depending upon the situation and whether or not the diagnosis can be adequately attained by history and physical examination. Tests may include a complete blood count (CBC) looking for anemia, electrolytes (especially sodium, potassium, calcium and magnesium), glucose, and creatinine (to check for kidney function). Thyroid function tests may also be considered.

If muscle spasms are prolonged and ongoing, there may be a concern that muscle breakdown and damage is occurring. A creatine phosphokinase (CPK) blood test can be used to detect this. It is an enzyme released into the bloodstream by irritated or damaged muscle tissue. If there is concern that the spasms are due to a nerve or muscle disorder, electromyography (EMG) may be done to determine whether there may be an abnormality of the muscle, of the nerves, or both.

If there is concern about the potential for peripheral artery disease, tests of blood flow to the legs may be considered, including an ankle-brachial index (ABI) which compares blood pressures in the arms and legs and ultrasound and angiography (often using CT or MRI) to directly assess the blood vessels. If nocturnal leg cramps are thought to be associated with a sleep disturbance, sleep studies might be indicated. 9/10

 

Prevention

This is the key to most skeletal muscle spasm episodes. Since they are often associated with dehydration and electrolyte disturbances, it is important to keep the body well hydrated. If the fluid loss is due to an illness with fever or vomiting and diarrhea, controlling the symptoms will help limit fluid loss and prevent spasms. Similarly, for those who work or exercise in a hot environment, drinking enough fluids to keep hydrated is very important. It is often helpful as well to hydrate prior to activities in warm environments.

Muscles should also be prepared for the activity that they are expected to do. Just as athletes stretch and warm up before the game, non-athletes should warm up before heavy labor, including jobs like raking, mowing, and shoveling snow. Should a large skeletal muscle go into spasm (often referred to as a charley horse), the initial treatment is to gently stretch the muscle back to length to break the spasm cycle and resolve the acute situation. Further treatment will depend upon the underlying cause of the muscle spasms. For muscles that have been damaged or strained, medications may be required for short-term pain relief, including anti-inflammatories, narcotics, and muscle relaxants.

The treatment of smooth muscle spasm, such as bowel spasm, also depends upon the underlying cause. Nocturnal leg cramps are difficult to control and treat. Historically, quinine has been prescribed to help with the muscle spasms, but this drug can have side effects including abnormal bleeding problems. Other medications, including B-complex vitamins, gabapentin and diltiazem, may be helpful.

Many possible treatments are available for the dystonias. The decision as to which medication to use depends upon the individual situation. It may take trial and error to find the right medication in the right dose to control symptoms.

▪ Anti-Parkinsonism drugs, like trihexyphenidyl HCl (Artane) and benztropine mesylate (Cogentin), decrease acetylcholine levels.
▪ Muscle relaxants like diazepam (Valium) and baclofen (Lioresal) affect GABA receptors.
▪ Levodopa (Sinemet) and reserpine (Harmonyl) affect dopamine levels.
▪ Carbamazepine (Tegretol), a seizure-control drug, may be useful in some patients.
▪ Botulinum toxin type A (Botox) may be injected into a specific muscle to paralyze it and relieve the muscle spasm of dystonia, such as for blepharospasms.

 

Culled from medicinenet.com

Compiled by Mr AbdRoheem Sorunke

Vanguard Pharmacy Limited

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