ENCEPHALITIS— INFLAMMATION OF THE BRAIN 223 



Diagnosis. — The diagnosis depends upon the symptoms of a 

 severe brain disturbance with which is associated well-defined 

 topical symptoms such as hemiplegia, monoplegia, ataxia, 

 facial paralysis, etc. If these symptoms occur with or follow 

 an infectious disease with which a non-suppurative encepha- 

 litis is apt to occur a diagnosis is possible. On the other hand, 

 primary encephalitis is quite difficult to diagnose unless both 

 the general and topical symptoms are well developed. From 

 purulent encephalitis the non-suppurative form can usually 

 be distinguished by the absence of injury to the cranium or 

 the absence of a primary abscess in some removed organ 

 or in the cranial wall. It may be impossible to distinguish 

 between encephalitis and meningo-encephalitis in those cases 

 of encephalitis in which the topical symptoms fail. Further- 

 more, in some cases of encephalitis the meninges may be also 

 involved. Encephalitis is distinguished from chronic hydro- 

 cephalus by its more sudden development, the severity of the 

 brain symptoms, and the presence of topical symptoms. 

 Encephalitis usually follows some infectious disease. From 

 forage poisoning encephalitis is distinguished by the severity 

 of the brain symptoms, the sporadic appearance of the dis- 

 ease, the absence of intestinal symptoms, and no history of 

 the animal's having eaten food which was moldy or otherwise 

 spoiled. 



Treatment. — The treatment is the same as for meningo- 

 encephalitis, and is usually of little aid to recovery. 



Suppurative Encephalitis (Abscess of ihe Brain). — Occur- 

 rence. — Brain abscesses are most apt to occur in young horses. 

 In the other domesticated animals abscess of the brain is 

 extremely rare. 



Etiology. — The most common cause of abscess of the brain 

 is strangles, which assumes the irregular form and leads to 

 internal metastatic abscesses. It may occasionally result 

 from other infectious diseases, such as puerperal septicemia, 

 purulent pneumonia, infectious pneumonia (with secondary 

 pus infection), and pyemia. Occasionally an abscess of the 

 brain may result from direct injury to the cranium or from 

 abscesses which occur in the neighborhood of the brain. In 

 rarer instances parasites (estrus, ccenurus, echinococcus in 



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