CHRONIC, HYDROCEPHALUS 247 



Course and Prognosis. — -The co.urse is usually from eight to 

 fourteen days. The mortality is over 90 per cent. Those 

 which recover are often left infirm through blindness, epilepsy, 

 permanent loin lameness or they remain "dummies." 



Treatment. — ^Treatment is of no avail. As a preventive it 

 is recommended to change the food and drinking water and to 

 keep the animals from infested pastm-es. Water from wells 

 and cisterns which are contaminated with stable seepage 

 should be especially avoided. 



CHRONIC HYDROCEPHALUS. 



Definition. — Chronic hydrocephalus is a brain disorder 

 common in horses, but rare in other animals caused by the 

 collection of serous fluid in the lateral ventricles of the brain. 

 It leads through pressure to dilatation of the lateral ventricles, 

 an increase in the size of the brain and an elevation of the 

 intracranial pressure. The condition is rarely congenital, 

 more often acquired. 



Etiology. — ^Two types of hydrocephalus may be distin- 

 guished from the standpoint of etiology: (a) Inflammatory 

 hydrocephalus, the result of acute inflammation of the brain 

 of which it is a sequel developing in about one month. In 

 this condition the fluid is an exudate, (b) A primary or 

 idiopathic hydrocephalus is probably of mechanical origin and 

 the fluid a transudate. It may be due to a congenital con- 

 striction or closing of the Sylvian aqueduct. An inherited 

 predisposition to this form of brain hydropsy is probable. 



Symptoms. — Chronic hydrocephalus in the horse is the 

 commonest cause of the so-called 'Mummy." There is 

 usually more or less disturbance in consciousness which the 

 animal shows by a number of clinical symptoms. The follow- 

 ing are the most characteristic all of which are made more 

 prominent by vigorous exercise : The attitude of the patient 

 is unphysiological, the head is held low, the limbs are fre- 

 quently misplaced, the legs being crossed, and the patient is 

 apt to stand diagonally in the stall. The patient seems 

 indifferent to its sm-roundings, is sleepy, the eyelids partially 

 closed, little attention is paid to commands, and an effort to 



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