636 Acute Non-purulent Encephalitis. 



Diagnosis. This can only be based on the appearance of 

 general or local sjanptoms indicating that the brain is involved 

 in diseases in wliich there is a known tendency for pyogenic 

 bacteria to invade the brain. The very acute cases cannot be 

 disting-nished from cases of acute meningitis. Cases in which 

 the course of the disease is slower can be differentiated by their 

 longer duration, the striking improvements which occur at 

 times, the absence of sensitiveness over the cranium and the 

 special local symptoms which not rarely make their appear- 

 ance. The presence of a primary abscess in some part of the 

 body is in itself no proof that the occurrence of cereljral sjanp- 

 toms is due to purulent encephalitis, because meningitis may 

 also occur under the same circumstances. One must also not 

 lose sight of the fact that in many cases of suppurative en- 

 cephalitis an animal that was previously apparently in perfect 

 health may become seriously ill owing to secondary meningitis 

 and succumb to it in a very short time. In cases of tumor for- 

 mation in the brain differential diagnosis can always be based 

 on the absolutely negative history of the disease, its slow de- 

 velopment, the presence of a primary growth in some other 

 organ, or in neighboring portions of the cranium, and finally 

 from the engorgement of the optic disc. A periodical rise of 

 temperature also indicates suppurative encephalitis. 



An accurate analysis of the focal symptoms that may be 

 present in cases that are not very acute renders a localization 

 of the disease possible, but a very careful investigation appears 

 to be necessary in this connection. 



Treatment. Provided a correct diagnosis has been made 

 regarding the nature and localization of the disease, and this in 

 the present state of knowledge is of rare occurrence, surgical 

 interference may be resorted to. Good results have followed 

 this treatment in the liuman subject. At the most a favorable 

 result might be expected in the case of an encapsuled abscess 

 superficially placed in a hemisphere; operation appears to be 

 hopeless from the outset in cases where there are multiple ab- 

 scesses deeply placed. 



Literature. Cad^ac, J. Vet., 1897, 28; 1907, 588.— Dexler, Nervcnkrkh. d. 

 Pferdes, 1899, 200 (Lit.).— Johne, S. B., 1879, 14.— Kofler, Monh., 1908, XIV, 

 71._Niei3g]^ Pj., Mt., 1856-57, 122.— Noack, S. B., 1893, 125.— Picard, Ann., 1904, 

 531. 



(b) Acute Non-purulent Encephalitis. Simple acute encephalitis. 



Acute non-purulent encephalitis results from an infection 

 or intoxication which in many cases is the result of an infectious 

 disease. In the majority of cases tliere are numerous centers 

 of disease and these may be hemorrhagic in character. 



Historical. In 1878 a case was recorded in the horse by Fried- 

 berger, and this was followed later by cases described by Thoraassen, 



