Muscle Cramps

Muscle Cramps Causes

Muscle cramps are felt to be caused by excessively excited nerves that stimulate the muscles. This can occur particularly 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 that are 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.
Common medications that can cause muscle cramps include furosemide (Lasix 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 Cramps Symptoms

Muscle cramps cause local pain, tenderness, and 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 to Seek Medical Care

Muscle cramps usually cause 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.

Exams and Tests

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 muscle cramps. 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).

Muscle Cramps Treatment

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.

Self-Care at Home

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 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.

Medications

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 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.