Spasms are contractions of the hands, thumbs, feet, or toes that are sometimes seen with muscle cramps, twitching, and convulsions (tetany). Spasms are usually brief, but they can be severe and painful.

Spasms of the hands or feet may be an important early sign of tetany, a potentially life-threatening condition. Tetany is due to a problem with the body's calcium levels, which can be linked to the following:

• Alkalosis in the body
• Ingestion of alkaline salts
• Lack of vitamin D
• Reduced function of the parathyroid glands (hypoparathyroidism)

The spasms are usually accompanied by the following symptoms:

• Cramping
• Fatigue
• Muscle weakness
• Numbness, tingling, or a "pins and needles" feeling
• Twitching
• Uncontrolled, purposeless, rapid motions

• Muscle cramps, usually caused by sports or occupational muscle injury
• Parkinson's disease
• Hypocalcemia (low calcium levels in the blood)
• Hypomagnesemia (low magnesium levels in the blood)
• Thyroid disorders
• Dystonia
• Huntington's disease
• Hyperventilation -- calcium becomes temporarily less available to the body during hyperventilation
• Damage to a single nerve or nerve group (mononeuropathy) or multiple nerves (polyneuropathy) that are connected to muscles
• Multiple sclerosis
• Use of certain medications