cramp

a prolonged and painful spasmodic muscular contraction that often occurs in the limbs but can affect certain internal organs (see COLIC and GASTRALGIA ). Cramp may result from a salt imbalance, as in heat cramp. Working in high temperatures causes excessive sweating and consequent loss of salt. It can be corrected and prevented by an increase of the salt intake. Occupational cramp results from continual repetitive use of particular muscles, e.g. WRITER'S CRAMP . Night cramp occurs during sleep and is especially common among elderly people, diabetics and pregnant women. The cause of night cramp is not known.