CHAPTER III 

 THE THYROID AND PARATHYROIDS (continued) 



EFFECTS OF REMOVAL OF THE PARATHYROIDS 



Parathyroidectomy. If the operation is complete i.e. if it includes all four 

 parathyroids most animals die as the result of the removal ; some within 

 a few days, others within a few weeks. The most acute symptoms are 

 exhibited by carnivora such as dogs, cats, foxes, and wolves (Vincent), and 

 the young of herbivora (v. Eiselsberg, Sutherland Simpson), and are of a 

 nervous nature. For the first day or two there are no symptoms, other 

 than some loss of appetite. There then supervenes marked exaltation of 

 reflexes, which leads to the occurrence from time to time of fibrillar con- 

 tractions of muscles, and later cramp-like and clonic contractions, with 

 eventually convulsive fits; these may be of considerable violence and 

 alternate with intervals of depression. The limbs in progression and the 

 tail are stiff and exhibit quiverings. The irritability of the peripheral 

 nerves to both electrical and mechanical stimuli is markedly increased. 

 The pulse is quickened and the heart-beat becomes greatly exaggerated. 

 There is profuse salivation. The body temperature may rise two or 

 three degrees centigrade during the fit. The paroxysms are usually accom- 

 panied by rapid gasping respirations which may be synchronous with the 

 heart-beats ; sometimes by vomiting and* diarrhcea. There is considerable 

 wasting. The hair tends to be shed. In the rat, Erdheim found that the 

 growing incisors fail to be properly calcified. Deficient calcification of the 

 teeth has also been found by Fleischmann to occur in children affected by 

 tetany. Death may occur within a few days, or the affection may last a 

 long time and spontaneous recovery may occur. The fits are sometimes 

 frequent, but more often occur at long intervals; the animal, if it fails 

 to recover from the effects of the removal, usually succumbs during a 

 convulsion. 



In man the contractions of muscles tend rather to take on a tonic 

 character: this is also observed in rats and puppies. In most animals 

 they are clonic. The tonic contractions are usually associated with 

 diminution of respirations and of frequency and force of heart-beats, and 

 with fall of body temperature : the clonic with increase, as above described. 

 The meaning of these differences is not clear. 



The syndrome is usually spoken of as " tetany " (tetania parathy- 

 reopriva) ; this is in no way synonymous with " tetanus." It may be acute 



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