242 DISEASES OF THE BRAIN 



follow infectious pneumonia or strangles in the horse, which 

 in some outbreaks of these diseases occurs more commonly 

 than in others. In rabies encephalitis, often hemorrhagic, is 

 occasionally well developed. 



Encephalitis may also result from sunstroke. Feeding 

 heavily on certain foodstuffs (legumes, rye) may predispose 

 the animal. 



Symptoms. — ^If encephalitis is secondary to some specific 

 infectious disease the symptoms of it may be masked by the 

 basic disorder. As a rule, the cerebral symptoms which 

 begin either gradually or quite rapidly (hemorrhage) manifest 

 themselves as disturbance in consciousness. The patient 

 appears languid, stupid, more or less oblivious of its sm-- 

 roundings, and assumes unphysiological postures. The gait 

 is staggering or the patient may be down in a soporous 

 or even comatose condition. Sometimes in the horse the 

 patient will show symptoms of cerebral excitement or even 

 rabiform sjonptoms. These are usually followed, however, 

 within a short time by stupor. The patient may show 

 forced movements. 



The topical symptoms are usually not determinable if 

 there is much mental depression. However, some of them 

 may be notable, such as paralysis of the pharynx, tongue, 

 larynx, eyelids, dilated pupils, etc. If the inflamniation of 

 the brain is diffuse a general paresis may result, the patient 

 being unable to regain its feet when down or walk without 

 support when up. If the respiratory center becomes 

 involved fatal dyspnea may result. Thq temperature is 

 usually elevated (105° F.), but the fever is mild and may be 

 entirely absent in protracted cases. The pulse is generally 

 in harmony with the temperature. Both are increased 

 during the stage of excitement. In the earliest stages the 

 appetite is good, provided the basic disease present has not 

 already interfered. If the mental depression is marked, 

 however, the patient may refuse to eat. 



Course. — ^The usual run of acute encephalitis is two to five 

 days. Subacute cases may last for weeks and chronic ones 

 for years, producing the so-called "dummy." 

 When the development is rapid, disturbance in conscious- 



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