Clonus vs. Tetany — What's the Difference?

Clonus is a set of involuntary and rhythmic muscular contractions and relaxations. Clonus is a sign of certain neurological conditions, particularly associated with upper motor neuron lesions involving descending motor pathways, and in many cases is, accompanied by spasticity (another form of hyperexcitability).

Tetany or tetanic seizure is a medical sign consisting of the involuntary contraction of muscles, which may be caused by disorders that increase the action potential frequency of muscle cells or the nerves that innervate them. Muscle cramps caused by the disease tetanus are not classified as tetany; rather, they are due to a lack of inhibition to the neurons that supply muscles.

An abnormality in neuromuscular activity characterized by rapidly alternating muscular contraction and relaxation.

A condition marked by intermittent muscular spasms, caused by malfunction of the parathyroid glands and a consequent deficiency of calcium.

(medicine) A muscular spasm with regular contractions.

An abnormal condition characterized by periodic painful muscular spasms and tremors, caused by faulty calcium metabolism and associated with diminished function of the parathyroid glands.

A series of muscular contractions due to sudden stretching of the muscle, - a sign of certain neuropathies.

(medicine) A condition characterized by painful muscular spasms, caused by faulty calcium metabolism

Convulsion characterized by alternating contractions and relaxations

A morbid condition resembling tetanus, but distinguished from it by being less severe and having intermittent spasms.

Clinical neurological syndrome characterized by muscular twitching and cramps and (when severe) seizures; associated with calcium deficiency (hypoparathyroidism) or vitamin D deficiency or alkalosis