PARATHYEOID GLANDS 683 



falls back upon tests for mechanical and electrical hyperexcitability of the 

 motor nerves. 



Raynaud's Disease. The sensory phenomena of Raynaud's disease 

 may simulate those of tetany, but tetany signs are not present in true Ray- 

 naud and the local anemias and asphyxias are very characteristic. Weber 

 has, however, suggested that Raynaud's disease may be a vasomotor tetany. 



IX. Prevention of Tetany 



If we are right in our belief that tetany often depends upon para- 

 thyroid insufficiency, three general principles may guide us in prophy- 

 laxis: (1) we should avoid removal of, or injury to, the parathyroid 

 glands in operations upon goiter; (2) we should avoid other conditions 

 believed to favor parathyroid insufficiency; and (3) when a predisposition 

 to tetany or a latent tetany is known to exist, the circumstances that may 

 release an attack or cause an exacerbation of the disease should be avoided. 



The operation for goiter has been so greatly improved that tetany from 

 now on will but rarely occur after thyroid operations. Any operator may, 

 of course, injure the parathyroids by accident, and, in a certain number 

 of cases, the surgeon will be compelled to remove one or more of the para- 

 thyroids on account of malignant growth. 



In the operation for goiter, resection is now done instead of total 

 lobectomy, in order to protect the parathyroid glands and the recurrent 

 laryngeal nerves and to preserve a slice of thyroid in case an operation has 

 to be performed later, possibly by another surgeon, on the opposite lobe. 

 In the resection of a lobe of the thyroid, the blood vessels undergo "ultrali- 

 gation" (well beyond the origin of the parathyroid arteries). Ligation of 

 the inferior thyroid artery is not practiced, and the wound is closed with- 

 out drainage. W. S. Halsted (e) has fully described all the improvements 

 in the operation in his recent monograph, "The Operative Story of Goitre" 

 (Baltimore, 1920). In case a parathyroid gland is accidentally removed 

 at operation and the discovery is made during the operation, it should be 

 immediately transplanted (preferably along with a small slice of thyroid) 

 into a preperitoneal pocket or at some other site where the graft may be 

 expected to grow. 



Avoidance of infection at the operation for goiter goes far toward 

 preventing scar formation with subsequent injury to the parathyroids or 

 to their blood supply. . 



We are much less well informed regarding methods of preventing the 

 forms of tetany other than postoperative tetany. Why tetany is especially 

 prevalent in certain places and "not in others we do not yet know, and it 

 is doubtful if much benefit would result from advising people to avoid 

 living in tetany towns. Even when certain of the occupants of such a place 



