A disorder characterized by muscle twitches, cramps, and carpopedal spasm, and when severe, laryngospasm and seizures. This condition is associated with unstable depolarization of axonal membranes, primarily in the peripheral nervous system. Tetany usually results from HYPOCALCEMIA or reduced serum levels of MAGNESIUM that may be associated with HYPERVENTILATION; HYPOPARATHYROIDISM; RICKETS; UREMIA; or other conditions. (From Adams et al., Principles of Neurology, 6th ed, p1490).