Tetany

: A combination of signs and symptoms, due usually to low calcium, that can include: {{}}Hyperreflexia (overactive neurological reflexes), Carpopedal spasm (spasms of the hands and feet), Cramps, and Laryngospasm (spasm of the larynx, the voice box). Tetany characteristically is considered to result from a severe degree of hypocalcemia (literally, very low calcium levels in the blood). It can also result from reduction in the ionized fraction of plasma calcium without marked hypocalcemia, as occurs in severe alkalosis (when the blood is highly alkaline). Although the calcium that is typically measured in laboratory medicine is the calcium in blood plasma, what really causes tetany is low ionic calcium in the extracellular fluid (between cells) and intracellular fluid (within cells). Tetany is characterized by sensory symptoms consisting of paresthesias (odd feelings) of the lips, tongue, fingers and feet; carpopedal spasm, which may be prolonged and painful; generalized muscle aching; and spasms of facial musculature. Tetany and tetanus sound alike and are easily confused. They both come from the same root, namely, from the Greek "tetanos" meaning convulsive tension. However, tetanus (lockjaw) is a specific disease marked by painful tonic muscular contractions caused by the toxin (tetanospasmin) made by the bacteria Clostridium tetani that acts upon the central nervous system.

* * *

A clinical neurologic syndrome characterized by muscle twitches, cramps, and carpopedal spasm, and when severe, laryngospasm and seizures; these findings reflect irritability of the central and peripheral nervous systems, usually resulting from low serum levels of ionized calcium or, less commonly, magnesium. Causes include hyperventilation, hypoparathyroidism, rickets, and uremia. SYN: intermittent cramp. [G. tetanos, tetanus]

- t. of alkalosis t. due to a loss of acid from the body or an increase in alkali, resulting in a reduction of ionized calcium in plasma and body fluids, e.g., hyperventilation t. (loss of CO₂), gastric t. (loss of HCl by vomiting), or injection or ingestion of excessive amounts of sodium bicarbonate.

- gastric t. t. associated with a gastric disorder, especially with loss of HCl by vomiting.

- hyperventilation t. t. caused by forced overbreathing, due to a reduction in CO₂ in the blood.

- hypoparathyroid t. SYN: parathyroid t..

- infantile t. t. of infants occurring usually in association with rickets, due to dietary deficiency of vitamin D.

- manifest t. t. from any cause in which neuromuscular hyperexcitability is clearly evident, as opposed to latent t.. SYN: symptomatic t..

- neonatal t. hypocalcemic t. occurring in neonates or young infants, due to transient functional hypoparathyroidism in consumption of cow's milk (high phosphorus content). SYN: myotonia neonatorum, tetanism.

- parathyroid t. t. due to lack of parathyroid function, spontaneous or following excision of the parathyroid glands. SYN: hypoparathyroid t., parathyroprival t..

- parathyroprival t. SYN: parathyroid t..

- phosphate t. t. due to the ingestion of an excess of alkaline phosphates (Na₂HPO₄ or K₂HPO₄); most commonly produced experimentally in animals by the injection of alkaline phosphate, which reduces the ionized calcium of the blood.

- postoperative t. parathyroid t. caused by injury to or excision of the parathyroids during procedures in the neck.

- symptomatic t. SYN: manifest t..

* * *

tet·a·ny 'tet-ən-ē, 'tet-nē n, pl -nies a condition of physiological calcium imbalance that is marked by intermittent tonic spasm of the voluntary muscles and is associated with deficiencies of parathyroid secretion or other disturbances (as vitamin D deficiency)

* * *

n.

spasm and twitching of the muscles, particularly those of the face, hands, and feet. Tetany is caused by a reduction in the blood calcium level, which may be due to underactive parathyroid glands, rickets, or alkalosis.

* * *

tet·a·ny (tetґə-ne) hyperexcitability of nerves and muscles due to decrease in concentration of extracellular ionized calcium, which may be associated with such conditions as parathyroid hypofunction, vitamin D deficiency, and alkalosis or result from ingestion of alkaline salts; it is characterized by carpopedal spasm, muscular twitching and cramps, laryngospasm with inspiratory stridor, hyperreflexia, and choreiform movements.