Symptoms and causes

Symptoms

Most muscle cramps develop in the leg muscles, particularly in the calf. Besides the sudden, sharp pain, you might also feel or see a hard lump of muscle tissue beneath your skin.

When to see a doctor

Muscle cramps usually disappear on their own and are rarely serious enough to require medical care. However, see your doctor if your cramps:

  • Cause severe discomfort
  • Are associated with leg swelling, redness or skin changes
  • Are associated with muscle weakness
  • Happen frequently
  • Don't improve with self-care
  • Aren't associated with an obvious cause, such as strenuous exercise

Causes

Overuse of a muscle, dehydration, muscle strain or simply holding a position for a prolonged period can cause a muscle cramp. In many cases, however, the cause isn't known.

Although most muscle cramps are harmless, some may be related to an underlying medical condition, such as:

  • Inadequate blood supply. Narrowing of the arteries that deliver blood to your legs (arteriosclerosis of the extremities) can produce cramp-like pain in your legs and feet while you're exercising. These cramps usually go away soon after you stop exercising.
  • Nerve compression. Compression of nerves in your spine (lumbar stenosis) also can produce cramp-like pain in your legs. The pain usually worsens the longer you walk. Walking in a slightly flexed position — such as you would use when pushing a shopping cart ahead of you — may improve or delay the onset of your symptoms.
  • Mineral depletion. Too little potassium, calcium or magnesium in your diet can contribute to leg cramps. Diuretics — medications often prescribed for high blood pressure — also can deplete these minerals.

Risk factors

Factors that might increase your risk of muscle cramps include:

  • Age. Older people lose muscle mass, so the remaining muscle can get overstressed more easily.
  • Dehydration. Athletes who become fatigued and dehydrated while participating in warm-weather sports frequently develop muscle cramps.
  • Pregnancy. Muscle cramps also are common during pregnancy.
  • Medical conditions. You might be at higher risk of muscle cramps if you have diabetes, or nerve, liver or thyroid disorders.
Feb. 16, 2016
References
  1. Muscle cramp. American Academy of Orthopaedic Surgeons. http://orthoinfo.aaos.org/topic.cfm?topic=A00200. Accessed Nov. 18, 2015.
  2. Winkelman JW. Nocturnal leg cramps. http://www.uptodate.com/home. Accessed Nov. 18, 2015.
  3. Muscle cramps. Merck Manual Professional Version. http://www.merckmanuals.com/professional/neurologic-disorders/approach-to-the-neurologic-patient/muscle-cramps. Accessed Nov. 18, 2015.