Muscle cramps

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Chest stretch

Muscle cramps

Definition:

Muscle cramps are involuntary and often painful contractions of the muscles which produce a hard, bulging muscle.

Muscle twitching (fasciculation) is the result of spontaneous local muscle contractions that are involuntary. Typically, these contractions only affect individual muscle groups connected to (innervated by) a particular motor neuron. This twitching does not cause pain.

Alternative Names:
Cramps - muscle
Considerations:

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Ordinary muscle cramps are common and may be stopped by stretching the affected muscle.

Muscle twitches are minor and often go unnoticed. Some are common and normal, while others indicate a neurologic disorder.

Common Causes:

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

Muscle fatigue
Heavy exercise
Dehydration
Pregnancy
Hypothyroidism
Depleted magnesium or calcium stores or other metabolic abnormalities
Alcoholism
Kidney failure leading to uremia
Medications

Muscle twitching may lead to cramping and may involve the following:

Benign, nonpathologic fasciculations (not caused by disease or disorders)
- Often affecting the eyelids, calf or thumb
- Commonly triggered by stress, anxiety
Diet deficiency
Side effects of drugs, especially diuretics or caffeine

More serious causes of fasciculations -- such as motor neuron disease, muscle diseases, or denervation -- are usually accompanied by weakness and atrophy of the affected muscle group, as well as other signs and symptoms.