Nocturnal Leg Cramps
By Roland J. Larrabee, M.D.
Benign nocturnal leg cramps are muscle spasms in the calf (also called a charley horse). They can occur one or many times during the night, lasting from a few seconds to a few minutes. Some people experience them regularly; others only on isolated occurrences.
Causes of Nocturnal Leg Cramps
Calcium and phosphorus imbalances can cause cramping, particularly during pregnancy. Low fluid levels in the body can also result in calcium and phosphorus imbalances that can cause leg cramps. This can occur from taking diuretics, excessive perspiration, vomiting, and diarrhea. Medical causes of muscle cramping include hypothyroidism, Addison's disease, uremia, and many diseases that affect nerves and muscles. Peripheral neuropathy, a complication of diabetes, in which the nerves in the extremities are impaired, can cause painful, numb, or tingling legs.
Risk Factors for Nocturnal Leg Cramps
Nocturnal leg cramps occur at all ages but peak at different times, particularly in adolescence, during pregnancy, and in old age. One study in campers reported an incidence of 7.3% in children older than eight (but not younger). The incidence increased at 12 years old and peaked at 16 to 18 years. Most adolescents with leg cramps reported that they had them one to four times per year. Pregnant women with low calcium levels due to an imbalance in calcium and phosphorus are at risk for leg cramps. (Such women should reduce milk intake because it does not redress this imbalance and should take non-phosphate calcium supplements.)
How Are Nocturnal Leg Cramps Treated?
Everyone with leg cramps should drink plenty of water to maintain adequate fluid levels. Experts advise nightly stretching exercises as the best preventive measures for leg cramps. While in bed, loose covers should be used to prevent pointing the toes, which causes calf muscles to contract and cramp. Propping the feet up higher than the torso may help.
Once a cramp begins, the patient should straighten the leg, flex the foot up or grab the toes and pull forward. Reducing milk intake and taking non-phosphate calcium supplements may help relieve leg cramps in pregnant women. Quinine had been used to prevent leg cramping but was banned by the FDA. Studies indicate it had only a slight benefit and some serious, although rare, side effects had been reported, including bleeding problems and heart irregularities. Other, less serious side effects include headaches, vision problems, and rash. Drinking tonic soda (which contains small amounts of quinine) before bedtime may be helpful. Other drugs tried for leg cramps without much success include vitamin E and potassium chloride.
Dr. Larrabee is Associate Director of Family and Community Medicine at the Walter L. Aument Family Health Center, 317 S. Chestnut St., Quarryville.