224 DISEASES OF THE BRAIN 



sheep ; Estrus bovis in cattle, and gastrophilus in the horse) 

 are causes. 



Symptoms. — The symptoms of brain abscess may develop 

 either very rapidly or gradually. In the former case the 

 symptoms are acute; in the latter, subacute. When the 

 symptoms develop rapidly the patient shows fever and not 

 infrequently mental excitement, even amounting to rabiform 

 symptoms. These may be followed by mental depression or 

 may persist until the death of the animal. The muscles may 

 twitch or undergo clonic spasms; forced movements are not 

 infrequently observed. The patient usually dies in a few days 

 or in less than two weeks. In other instances, as noted, the 

 symptoms develop gradually, the patient showing disturbance 

 in consciousness, forced movements, usually walking in a 

 circle. There may be occasional manifestations of cerebral 

 excitement; epileptiform attacks with intervals between dur- 

 ing which the patient appears normal. The temperature may 

 not be increased, although usually it is intermittent or remit- 

 tent in type (pus temperature) . Topical symptoms, such as 

 sudden blindness in one or both eyes; the pupils may react 

 unsymmetrically. Hemiplegia has also been observed. The 

 head of the patient is often held to one side and attempts to 

 straighten it cause symptoms of excitement. Some patients 

 show vertigo, irregular gait, and a tendency to fall while in 

 motion. Sometimes pressure on the poll produces epilepti- 

 form convulsions. 



Diagnosis. — The diagnosis depends very largely upon the 

 history of the case, i. e., whether or not the patient has 

 suffered from a disease of suppurative character (strangles, 

 puerperal septicemia) . The acute form of abscess of the brain . 

 cannot be distinguished from many cases of acute encepha- 

 litis or meningo-encephalitis. On the other hand, brain abscess 

 which assumes a subacute course may be distinguished by the 

 periodicity of the brain attacks between which the animal 

 may seem in good health, a remittent fever (take temperature 

 for several days), the absence of sensitiveness of the poll, and 

 the peculiar topical symptoms shown. As meningo-encepha- 

 litis may also result from a primary abscess the presence of such 

 an abscess does not necessarily speak for abscess of the brain. 



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