TETANY 177 



relative insufficiency of the parathyroids (Jeandelize, Pineles, Escherich, 

 Erdheim, Chvostek, Jr., Rudinger, and others). 



a. Aparathyrosis or Hypoparathyrosis, Tetany 



Definition. By letany we mean an abnormally increased condition of 

 excitement of the nervous system, which is demonstrable in a heightened excitability 

 of the motor, sensible, sensory and vegetative neroes, and under certain circum- 

 stances, in paresthesias, and bilateral intermittent, for the most part painful, 

 spasms, with intact consciousness, or which becomes manifest through phenomena 

 of irritation on the part of the vegetative nerves. To the picture of tetany belong 

 also trophic and certain metabolic disturbances. The manifestations are the 

 result of an insufficiency of the parathyroid glands. 



Symptomatology/ Increase in the electric excitability is to be regarded, 

 next to spasms, as the most important cardinal symptom of tetany. It 

 affects in the first place the peripheral motor nerves (Erb), although the sen- 

 sory senses (Hoffman], and the nerves of special sense (acusticus-Chvostek, 

 Jr.), are overexcitable to electricity. This hyperexcitability is found espe- 

 cially on the use of the galvanic current; the faradic excitability is most often 

 normal. The ulnar nerve serves best for testing in adults; the peroneal 

 nerve in children. We should use Stintzing's normal electrode (3 sq. cm.) 

 and Edelmann's horizontal galvanometer. The hyperexcitability expresses 

 itself not only in a lessening of the irritation threshold against the cathodal 

 closing contraction, but also in a definite alteration of the contraction formula. 

 In normal individuals the lower limits for the C.C.C. lies at about 0.9 milli- 

 ampere for the ulnar nerves, for the A.C.C. at about 1.5 to 2 milliamperes, 

 for the A.O.C. about 2.5-3 milliamperes, for the C.C.Te about 5 milli- 

 amperes, and the C.O.C. can hardly be obtained even with high amperage. 

 Now in tetany the C.C.C. can fall to very low values (as low as o. i milli- 

 ampere, and also the values for A.C.C. fall (even to 0.5 milliampere) ; it is 

 important, however, that the value for the A.O.C. fall and eventually be- 

 come lower than that of A.C.C. and even lower than that of C.C.C. Further 

 C.C.Te occurs at very low values, and finally also C.O.C. may be ob- 

 tained. Also A.C.Te and A.O.Te may be obtained sooner. The first 

 statements as to the galvanic hyperexcitability came from Kussmaul and 

 Benedict; the first exact measurements were made by Erb. In the tetany 

 of children, first Escherich and Jauregg v. Wagner pointed out the galvanic 

 hyperexcitability. Thiemich regarded the falling of C.O.C. below 5 milli- 

 amperes as conclusive for the diagnosis. It was shown, however, by v. 

 Pirquel that this relation obtains only in the most severe cases and that the 

 slight grades of tetany are first recognized in a falling of the value for A.O.C., 

 in the so-called anodal hyperexcitability. 



ErVs phenomenon may be present in the most of the motor nerves ac- 



