Muscle cramps are involuntary and often painful contractions (movements) of the muscles.

Muscle cramps are common and may be stopped by stretching the muscle. The cramping muscle may feel hard or bulging.

Muscle spasms are different than muscle twitches, which are covered in a separate article.

Muscle spasms can cause cramps and are usually brought on by the following:

• Alcoholism
• Dehydration
• Heavy exercise
• Hypothyroidism
• Kidney failure
• Medications
• Muscle fatigue
• Metabolic problems
• Pregnancy
• Reduced levels of magnesium or calcium in the body

Slow stretching often brings relief. If muscle cramps continue, see your doctor.

Call your doctor if your muscle cramps are severe, last a long time, or keep coming back and do not go away with simple stretching.

Your health care provider will perform a physical examination and ask questions about your medical history, such as:

• When did the spasms first begin?
• How long do they last?
• How often do you experience muscle spasms?
• What muscles are affected?
• Is it always the same location?
• Are you pregnant?
• Have you been vomiting, had diarrhea, excessive sweating, excessive urine volume, or any other possible cause of dehydration?
• What medications do you take?
• Have you been exercising heavily?
• Have you been drinking alcohol heavily?

Tests that may be done include:

• Blood tests for disorders of the following:
  • Calcium, potassium, or magnesium metabolism
  • Kidney function
  • Thyroid function
• Electromyography
• Myelography
• Pregnancy test

Pain relievers (analgesics) may be prescribed.

Skorecki K, Ausiello J. Disorders of Sodium and Water Homeostasis. In: Goldman L, Ausiello D, eds. Goldman: Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 117.

Molitoris B. Acute Kidney Injury. In: Goldman L, Ausiello D, eds. Goldman: Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 121.

Barohn R. Muscle Diseases. In: Goldman L, Ausiello D, eds. Goldman: Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 447.