The Collaborative International Dictionary of English v.0.48:

Tetany \Tet"a*ny\, n. (Med.)
   A morbid condition resembling tetanus, but distinguished from
   it by being less severe and having intermittent spasms.
   [1913 Webster]

WordNet (r) 3.0 (2006):

tetany
    n 1: clinical neurological syndrome characterized by muscular
         twitching and cramps and (when severe) seizures; associated
         with calcium deficiency (hypoparathyroidism) or vitamin D
         deficiency or alkalosis [syn: tetany, tetanilla,
         intermittent tetanus, intermittent cramp, apyretic
         tetanus]