Restless Legs Syndrome and Related Disorders - Diagnosis

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Meralgia Paresthetica. An uncommon nerve condition, meralgia paresthetica causes numbness, pain, tingling, or burning on the front and side of the thigh. It usually occurs on one side of the body, and the cause may be compression of the thigh nerve as it passes through the pelvis. It typically occurs in people aged 30 - 60 years, but it can affect people of all ages. It often goes away on its own.

Nocturnal Leg Cramps

Cramps that awaken people during sleep are very common, and they are not part of restless legs syndrome or periodic limb movement disorder. They can be very painful and may cause a person jump out of bed in the middle of the night. They typically affect a specific area of the calf or the sole of the foot.

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What Are Nocturnal Leg Cramps?

Benign nocturnal leg cramps, sometimes known as a charley horse, are muscle spasms in the calf that can occur one or many times during the night. Cramping may also occur in the soles of the feet. They typically last from a few seconds to a few minutes. Some people experience them regularly, others only on isolated occurrences.

Causes of Nocturnal Leg Cramps. In most cases, the cause of nocturnal leg cramps remains unknown. Among the conditions that might cause leg cramps are:

• Calcium and phosphorus imbalances, particularly during pregnancy
• Low potassium or sodium levels
• Overexertion, standing on hard surfaces for long periods, or prolonged sitting (especially with the legs contorted)
• Having structural disorders in the legs or feet (such as flat feet)
• Medical causes of muscle cramping include hypothyroidism, Addison's disease, uremia, hypoglycemia, anemia, and certain medications. Various diseases that affect nerves and muscles, such as Parkinson's, cause leg cramps. Peripheral neuropathy, a complication of diabetes, can cause cramp-like pain, numbness, or tingling in the legs. Patients with kidney disease undergoing dialysis are also prone to leg cramps.

Individuals at Higher Risk for Nocturnal Leg Cramps. Nocturnal leg cramps occur at all ages but peak at different times. They are particularly common in adolescence, during pregnancy, and in older age, affecting up to 70% of adults over age 50 at some point.

Pregnant women and those taking diuretics are also at risk for leg cramps because of low calcium levels and an imbalance in calcium and phosphorus.

Consequences of Nocturnal Leg Cramps. Nocturnal leg cramps, like restless legs syndrome, rarely have any serious consequences. However, they can be extremely painful and long lasting. In some cases, severe and persistent symptoms can cause chronic insomnia and considerable mental distress.

Managing Nocturnal Leg Cramps

Once a cramp begins, straighten the leg, flex the foot upward toward the knee, or grab the toes and pull them toward the knee.

Walking or shaking the affected leg, then elevating it, may also help.

If soreness persists, a warm bath or shower or an ice pack may bring relief.

Lifestyle Tips for Preventing Nocturnal Leg Cramps. Nighttime leg cramps are generally treated with lifestyle changes.

• Everyone with leg cramps should drink plenty of water (at least 6 - 8 glasses daily) to maintain adequate fluid levels.
• To prevent cramps from occurring, nightly stretching exercises may be the best preventive measure (these are generally recommended for RLS, as well). Patients should stand about 30 inches from a wall and, keeping the heels flat on the floor, lean forward and slowly move the hands up the wall to achieve a comfortable stretch. A few minutes on a stationary bicycle at bedtime may also help.
• While in bed, loose covers should be used to prevent the toes and feet from pointing, which causes calf muscles to contract and cramp. Propping the feet up higher than the torso may also help.
• During the week, swimming and water exercises are a good way to keep muscles stretched, and wearing supportive footwear is also important.

Quinine. Quinine had been widely used to prevent leg cramping. The U.S. Food and Drug Administration (FDA) banned its sale over the counter because it reportedly caused some serious, although rare, side effects. These side effects include bleeding problems and heart irregularities. Other, less serious side effects include headaches, vision problems, and rash.

The FDA has since banned the marketing of most quinine drugs, cautioning against the off-label (non-approved) use of the drug to treat nocturnal (nighttime) leg cramps. Only one form of the drug, Qualaquin, is approved for sale, for the treatment of some types of malaria. Pregnant women and those with liver problems should avoid quinine in any form. In July 2010 the FDA issued a warning of serious, potentially life-threatening side effects resulting from the use of Qualaquin for nocturnal leg cramps. These side effects include dangerously low platelet levels in the blood (platelets help the blood clot) and permanent kidney damage.

Supplements. Some small studies indicate that the mineral magnesium, taken as magnesium citrate or magnesium lactate, may provide some benefit to people with leg cramps, including pregnant women.

In one small study, taking vitamin B complex was helpful. Other supplements tried for leg cramps include vitamin E, calcium, and potassium or sodium chloride, but these do not appear to be very effective. Sodium chloride (salt) may be helpful, but Western diets already contain too much sodium.

Review Date: 10/15/2010
Reviewed By: Reviewed by: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org).