Infection, in traumas, meningitis, encephalitis, strangles, etc.
Symptoms: evidence of trauma, chill, hyperæsthesia irritability,
drowsiness, giddiness, stupor, spasms, paresis, coma, dilated pupils,
congested mucosæ, vomiting. Location indicated by muscular groups
involved. Treatment: As in meningitis: trephining in hopeful cases.
The formation of abscess in the cranial cavity has been referred to in
connection with injuries to the cranium and meningo-encephalitis. It may
here be said in general terms that this abscess is a product of
infection. In the horse the most common cause is strangles, and
especially such cases as run a tardy or irregular course with imperfect
softening and limited suppuration in the submaxillary or pharyngeal
region. It is to be looked on as an extension of the purulent infection
so as to cause a secondary abscess. The same may occur in case of
ordinary abscess in any distant organ. In the brain as elsewhere
suppuration may result from direct local injury as in the case of blows
by clubs, or yokes, running against walls or posts, falls, the effects
of butting, injuries by bullets and otherwise. In these cases, as
noticed under concussion, there may be two points of injury (and two
abscesses) one, in the seat of the injury, and one in a deeper part of
the brain, at the opposite wall of the cranium. Again abscess may result
in the brain from extension from a similar process going on in the
vicinity. Thus otitis extends through the middle and internal ear to the
brain, and its starting point may have been more distant, namely, in the
Eustachian tube, or pouch, or in the pharynx.
The _symptoms_ vary according to the size of the abscess, the rapidity
of its formation and the amount of attendant congestion. In the common
cases resulting from strangles, I have usually found the animal down,
unable to rise, blind, amaurotic, with dilated pupils, congested mucous
membranes, and occasional spasmodic movements of the limbs, neck and
head. The symptoms may, however, vary through hyperæsthesia,
irritability, drowsiness, giddiness, stupor, local or general paralysis
with occasional spasms or convulsions. There may be an initial
shivering, and a rise of temperature, yet as pressure on the brain
increases it may become normal or subnormal. In circumscribed abscess
the symptoms may be much less severe, not perhaps exceeding
irritability, drowsiness, and some paresis or local paralysis.
In some such cases one can trace the connection to some primary disease,
(traumatic injuries to the cranium, abscess of the diplöe or sinus,
parasites in the sinus, otitis, or pharyngeal disease) which serve as an
indication of the true state of things. In others there may be
circumscribed local manifestations, (anæsthesia, hyperæsthesia,
hemiplegia, paralysis of special muscular groups, or spasms of the same
) which may indicate more or less accurately the exact seat of the
lesion. When well defined, this localization of the resultant phenomena,
serves to distinguish this and other local lesions, from meningitis
which is apt to be much more general in its diffusion. In the carnivora
and omnivora vomiting is a marked symptom.
_Treatment_ of brain abscess is usually hopeless, yet the attendant
inflammation may be met as in other cases of meningitis. If the seat of
abscess can be ascertained surgical interference is fully warranted.