What Is a Muscle Cramp?
As we normally use our muscles, they alternately contract and relax as we move our limbs back and forth. Similarly, the muscles that maintain our posture contract and relax in a synchronized fashion. A muscle that involuntarily contracts without our consciously willing it is called a "spasm." If the spasm is forceful and sustained, it becomes a cramp. A muscle cramp is an involuntarily and forcibly contracted muscle that does not relax. Muscle cramps cause a visible or palpable hardening of the involved muscle.
Muscle cramps can last anywhere from a few seconds to a quarter of an hour or occasionally longer. It is not uncommon for a cramp to recur multiple times until it finally goes away. The cramp may involve a part of a muscle, the entire muscle, or several muscles that usually act together, such as those that flex adjacent fingers. Some cramps involve the simultaneous contraction of muscles that ordinarily move body parts in opposite directions.
Muscle cramps are extremely common, and nearly everyone experiences a cramp at some time in their life. Cramps are common in adults and become increasingly frequent with aging. However, children also experience cramps.
Any of the muscles that are under our voluntary control (skeletal muscles) can cramp. Cramps of the extremities, especially the legs and feet, and most particularly the calf (the classic "charley horse"), are very common. Involuntary muscles, those we cannot control, of the various organs (heart, uterus, blood vessel wall, intestinal tract, bile and urine passages, bronchial tree, etc.) are also subject to spasms and cramps but will not be further considered in this review. This article focuses on cramps of the muscles that move joints, the muscles we can consciously control, the voluntary muscle known as skeletal muscle.
What Causes Muscle Cramps?
Muscle cramps are felt to be caused by excessively excited nerves that stimulate the muscles. This can occur after injury to nerve and/or muscle; dehydration; with low blood levels of calcium, magnesium, or potassium; from certain medications; and even at rest. The pain that is associated with muscle cramps caused by poor circulation to the legs that worsens with walking is referred to as claudication. Deficiencies of certain vitamins, including thiamine (B1), pantothenic acid (B5), and pyridoxine (B6), can also cause muscle cramps.
Medications that can cause muscle cramps include furosemide (Lasix, a diuretic), donepezil (Aricept for Alzheimer's disease), neostigmine (Prostigmin for myasthenia gravis), raloxifene (Evista to prevent osteoporosis in postmenopausal women), tolcapone (Tasmar for Parkinson's disease), nifedipine (Procardia for angina, high blood pressure), and the asthma drugs terbutaline (Brethine) and albuterol (Proventil, Ventolin, and others). Some medicines used to lower cholesterol, including clofibrate (Atromid-S), pravastatin (Pravachol), atorvastatin (Lipitor), and lovastatin (Mevacor), can also cause cramps.
Muscle Cramp Remedies and Treatments
A muscle cramp is a sustained muscle spasm. There are many causes of muscle cramps. The pain from muscle cramps can range from mild to incapacitating. Massaging and stretching may provide relief of muscle cramps.
What Are Risk Factors for Developing Muscle Cramps?
Risk factors for developing muscle cramps include certain medications (such as those listed in the section above), exercise, dehydration, and low blood levels of calcium, magnesium, potassium, vitamin B1, B5, or B6.
What Are Muscle Cramp Symptoms and Signs?
Muscle cramps cause the following:
- Local pain
- Firmness of the involved muscle
This disturbs the function of the involved extremity. When a hand muscle is affected, it can lead to difficulty in writing (writer's cramp) or grasping. When the muscles of the calf or foot are affected, it can lead to difficulty walking.
When Should Someone Seek Medical Care for Muscle Cramps?
Muscle cramps usually are a temporary nuisance and typically resolve on their own without treatment. When muscle cramps continually recur, it is time to seek an evaluation by a health-care professional.
What Specialists Treat Muscle Cramps?
While primary-care doctors most commonly treat muscle cramps, other specialist physicians who can be involved include orthopedists, rheumatologists, physiatrists, neurologists, and intensive-care physicians.
What Tests Do Health-Care Professionals Use to Diagnose Muscle Cramps?
The health-care professional will review your history to analyze the character, location, intensity, and frequency of your muscle cramps. Your medications will be reviewed to determine if they may be playing a role in causing your symptoms. The physical examination will include evaluation of muscle strength, dexterity, and nerve function. Blood tests for the muscle enzymes (CPK, aldolase, LDH, ALT, AST) can be helpful to determine if muscle injury is occurring. Other blood testing may include evaluation of the levels of calcium, phosphorus, potassium, and magnesium, as well as thyroid function. Occasionally, testing with a neurologist might include tests of nerve conduction velocity (NCV) and an electromyogram (EMG).
What Are Home Remedies for Muscle Cramps?
Most cramps can be stopped if the involved muscle can be stretched. For many cramps of the feet and legs, this stretching can often be accomplished by standing up and walking around. For a calf muscle cramp, the person can stand about 2-2½ feet from a wall (possibly farther for a tall person) and lean into the wall to place the forearms against the wall with the knees and back straight and the heels in contact with the floor. Another technique involves flexing the ankle by pulling the toes up toward the head while still lying in bed with the leg as straight as possible. For a writer's cramp (contractures in the hand), pressing the hand on a wall with the fingers facing down will stretch the cramping finger flexor muscles.
Gently massaging the muscle will often help it to relax, as will applying warmth from a heating pad or hot soak. If the cramp is associated with fluid loss, as is often the case with vigorous physical activity, fluid and electrolyte (especially sodium and potassium) replacement is essential. Medicines are not generally needed to treat an ordinary cramp that is active since most cramps subside spontaneously before enough medicine would be absorbed to even have an effect.
What Is the Treatment for Muscle Cramps?
The primary treatment of muscle cramps involves methods to relax the affected muscle. This typically involves stretching, massage, and heat application. Other treatments are directed toward the underlying cause of the muscle cramps and can include rehydration, electrolyte repletion, hormone treatment, calcium supplementation, etc.
Are There Medications That Treat Muscle Cramps?
Muscle relaxants such as cyclobenzaprine (Flexeril), orphenadrine (Norflex), and baclofen (Lioresal) can be helpful to relax cramping muscles. Some people benefit by drinking simple quinine-containing water (tonic water) before bedtime. In recent years, injections of therapeutic doses of botulism toxin (Botox) have been used successfully for some spastic muscle disorders that are localized to a limited group of muscles. A good response may last several months or more, and the injection may then be repeated.
Persisting muscle cramps can require blood testing and an evaluation by a neurologist. Return to your health-care professional if your muscle cramps recur.
Your follow-up with your health-care professional can be important to detect associated activities or diseases that should be addressed to stop your muscle cramping.
Is It Possible to Prevent Muscle Cramps?
Stretching is recommended before and after for cramps that are caused by vigorous physical activity. An adequate warm-up and cooldown before and after activity can help prevent muscle cramps. Adequate hydration before, during, and after physical activity is important, especially if the duration exceeds one hour, and replacement of electrolytes (especially sodium and potassium, which are major components of perspiration) can also be helpful. Excessive fatigue, especially in warm weather, should be avoided. Supplemental calcium and magnesium have each been shown to help prevent cramps associated with pregnancy. Drinking quinine (tonic water) before bedtime can alleviate night cramps.
What Is the Prognosis for Muscle Cramps?
Although cramps can be a great nuisance, they are a benign condition. Their importance is limited to the discomfort and inconvenience they cause or to the diseases associated with them. Careful attention to the preceding recommendations will greatly diminish the problem of cramps for most individuals. As mentioned, those with persistent or severe muscle cramps should seek medical attention.
Reviewed on 11/20/2017
Harrison's Principles of Internal Medicine, McGraw-Hill, Mar 2008.