674: LEWELLYS F. BARKER 



can he sure that tetany exists. Especially in the tetany of infancy is the 

 test for increased galvanic excitability very important, as has heen shown 

 by the exact studies of Thiemich and of von Pirquet (a) (b) in Europe and 

 by those of H. B. Wilcox, J. P. Sedgwick, J. B. Holmes, and others in 

 America. Indeed, increased electrical excitability is now regarded as the 

 most reliable sign for the detection of tetany in young infants. Marked al- 

 terations of the electrical excitability, such as we find in tetany, are not 

 observable in any other disease, and if found to be present, they are like an 

 outspoken facial phenomenon, decisive for the positive diagnosis of tetany. 

 In latent tetany, and in the intervals between attacks in acute tetany, Erb's 

 phenomenon is, however, less often found positive than is Chvostek's sign. 

 A disadvantage, too, of the electrical excitability test is its circumstantial- 

 ity. The electric battery must be at hand, and one must have some skill in 

 applying it, though this skill is very easily acquired. The test for Chvo- 

 stek's phenomenon, on the other hand, is so simple that it can be applied in 

 a moment anywhere and by any one. 



Trousseaus phenomenon is very helpful in the diagnosis of tetany, for 

 when it is positive it is exceedingly characteristic, but it is not infrequently 

 negative in undoubted cases of tetany, and may not be demonstrable even in 

 cases of acute tetany. Moreover, when the tetany begins to die down, 

 Trousseau's phenomenon tends to disappear more quickly than either 

 Chvostek's sign or Erb's phenomenon. In hysteria, a so-called pseudo- 

 Trousseau phenomenon is said sometimes to occur on pressure over the 

 ovaries or upon a spinous process of a vertebra. 



The test for the leg phenomenon of Pool, as well as that for his arm 

 phenomenon, is easy to apply. According to Schlesinger, the test for the 

 leg phenomenon will yield a positive result in some cases in which the test 

 for Trousseau's sign is negative. 



The other tetany symptoms (Hoffmann, phenomenon, galvanic hyper- 

 esthesia of the acusticus, myotonic phenomena, fibrillation of single mus- 

 cles, the tetany face, and trophic disturbances in the nails, hair, teeth and 

 crystalline lens) should all be kept in mind and should be looked for in 

 doubtful cases. In such instances, too, an injection of old tuberculin may 

 call forth an attack and this test has therefore sometimes been applied for 

 diagnostic purposes (Chvostek). 



The positive signs and symptoms in tetany are found to vary greatly, 

 presumably, according to the degree of insufficiency of the parathyroid 

 gland that exists in different cases. According to degree of intensity of 

 the tetany, the cases may be grouped as follows: 



1. Mildest cases. No symptoms of tetany present except a positive 

 Chvostek's sign. 



2. Tetanoid slate of von Frankl-IIochwart. Paresthesias, feelings of 

 stiffness in the muscles, with atypical cramps in certain circumstances 

 (extension of the trunk on grasping objects, cramps in the calves on exten- 



