Health Encyclopedia

Muscle twitching

Definition

Muscle twitches are fine movements of a small area of muscle.

Alternative Names

Muscle fasciculation; Fasciculations of muscle

Considerations

Muscle twitching is caused by minor muscle contractions in the area, or the uncontrollable twitching of a muscle group that is served by a single motor nerve fiber or filament.

Muscle twitches are minor and often go unnoticed. Some are common and normal. Others are signs of a nervous system disorder.

Common Causes

Diet deficiency
Drug overdose (caffeine)
Drug side effect (such as from diuretics, corticosteroids, or estrogens)
Exercise
Twitches not caused by disease or disorders (benign twitches)
- Often affecting the eyelids, calf, or thumb
- Normal and quite common, often triggered by stress or anxiety
- Come and go, and do not last for more than a few days

Nervous system conditions that can cause muscle twitching:

Amyotrophic lateral sclerosis (ALS - Lou Gehrig's disease)
Damage to the nerve that leads to a muscle
Muscular dystrophy
Spinal muscular atrophy
Weak muscles (myopathy)

Symptoms that suggest a nervous system disorder include:

Loss of, or change in sensation
Loss of muscle size (wasting)
Weakness

Home Care

There is usually no treatment necessary for benign muscle twitching.

Call your health care provider if

Call your health care provider if you have long-term or persistent muscle twitches.

What to expect at your health care provider's office

Your health care provider will take a medical history and perform a physical examination.

Medical history questions may include:

When did you first notice the twitching?
How long does it last?
How often do you experience twitching?
What muscles are affected?
Is it always in the same location?
Are you pregnant?
What other symptoms do you have?

Diagnostic tests vary depending on the suspected cause. Tests may include:

Blood tests to look for problems with electrolytes, thyroid gland function, and blood chemistry
Electromyogram
Nerve conduction studies
MRI of the spine, and sometimes of the brain

References

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

Review Date:11/13/2008
Reviewed By:David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Daniel B. Hoch, PhD, MD, Assistant Professor of Neurology, Harvard Medical School, Department of Neurology, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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