SPASMS OF THE DIAPHRAGM 247 



CHOREA. SAINT VITUS' DANCE. 



Definition. — Chorea, or Saint Vitus' dance, is an involun- 

 tary, rhythmic twitching of certain muscles, producing irregu- 

 lar jerking movements usually in the head, eyelids, and 

 facial muscles, and occasionally of the limbs. 



Etiology. — The cause in animals seems to be a brain neu- 

 rosis. Chorea-like twitchings sometimes result from dis- 

 temper in dogs. This, however, is a sequela of encephalitis 

 or meningo-encephalitis and is not a true chorea. 



SPASMS OF THE DIAPHRAGM. 



Definition. — A rhythmic spasmodic contraction of the 

 muscles of the diaphragm, with which is usually associated 

 clonic spasms of the abdominal muscles. 



Occurrence. — Spasms of the diaphragm are most frequently 

 noted in horses. Exceptionally cases have been described in 

 cattle. 



Etiology. — Digestive disturbances of an acute character 

 affecting the stomach (acute catarrh, bloating), bowels 

 (catarrh or constipation). Very probably toxic substances 

 absorbed from the gastro-intestinal contents reflexly stimu- 

 late the nerves of the diaphragm, producing the symptoms. 

 Overexertion, especially when accompanied by mental excite- 

 ment (runaways, overdriving, pulling an object of which the 

 horse is afraid), may also induce it. Acute inflammatory 

 diseases of the thoracic organs and pleura may be occasional 

 causes. 



Symptoms. — The symptoms are somewhat similar to those 

 of palpitation of the heart, except that the spasms do 

 not occur synchronously with the pulse. They consist in 

 rhythmic, electric-stroke-like shocks, which can be seen and 

 felt especially along the ribs, the loins, hollow of the flank, 

 and over the chest. If the hand is placed upon the patient, 

 throbs may be felt which are most intensive over the dia- 

 phragmatic attachments. While coincidentally the number 

 of beats may be equal to those of the heart, they are generally 

 less in number (ten to fifteen per minute) and do not corre- 



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