Definition. Causes: leaps, trips, falls, blows. Symptoms: fall,
insensibility, flaccidity, suspended respiration, tumors, vomiting,
recovery, signs of cerebral congestion. Pathology: anæmia followed by
congestion. Diagnosis: from fracture, epilepsy. Treatment: quiet,
rubbing of limbs, ammonia, cold to head, or heat; for congestion,
bromides, depletion, ice pack, derivatives.
_Definition._ Concussion is the condition produced by mechanical jar or
shock of the cerebral mass, and manifested by modification of the brain
functions of any grade from a simple dazed condition to that of complete
unconsciousness.
_Causes._ The most familiar cause is the stroke of the butcher’s pole
axe, producing sudden and absolute insensibility. A horse in leaping,
trips and falls on his head or running against a wall sustains a
concussion, which leaves him for some seconds without any signs of life.
The same will happen to other animals, but above all to rams which in
their combats, back for a number of yards and running together meet with
a shock from the effect of which even their thick skulls cannot save
them. Other blows upon the head operate to the same end.
_Symptoms._ Concussion is manifested by different grades of symptoms. At
first there is usually a fall with complete insensibility. The animal
lies flaccid, utterly insensible to external irritation and there is
suspension of respiration. The heart continues to beat and a frequent
weak pulse may be often detected. In slight cases, breathing may be
reestablished at the end of a minute or two, with muscular tremors and
movements of the limbs; then the animal rises, shakes his head, neighs,
and walks at first unsteadily and afterward with greater and greater
firmness. In vomiting animals, emesis occurs.
In some cases this may be followed, after an hour or two, by signs of
congestion, heat of the head, redness of the eyes, irritability, or
dullness and stupor and perhaps muscular twitching. This may improve or
it may terminate in death preceded by spasms, general convulsions,
rolling of the eye balls, and stupor or coma with general muscular
relaxation.
The primary condition is usually an anæmia of the cerebral matter as
seen in the brain of the animal suddenly killed by the blow of a hammer.
The return of consciousness or semi-consciousness is connected with the
resumed freedom of the cerebral circulation. The later convulsions,
stupor or coma, usually imply active congestion or the effusion of blood
on the brain surface, or in its substance.
_Diagnosis_ from fracture must be made mainly by manipulation of the
bone in the seat of the blow, and by the absence of the increasing
stupor and coma which attend on pressure from a gradually increasing
blood clot. From epilepsy it is to be distinguished by the evidence of
mechanical injury, by the absence of spasms at the first, by the
suspension of breathing and the absence of froth about the lips.
_Treatment._ Keep the patient still and prostrate until there are signs
of returning respiration and free cerebral circulation. This may be
hastened, however, by active rubbing of the limbs and body, by giving
guarded inhalations of ammonia, or even by friction of the skin with
ammonia and oil. Sometimes reaction is favored by dashing cold water on
the head, while in other cases hot water to the poll will prove more
effective, or the two may be used alternately with good results.
If, after partial recovery, there is marked restlessness, or
irritability it may be met with bromides. If secondary unconsciousness
supervenes effusion of serum or blood is to be feared, or extreme
congestion, and blood may be drawn from the jugular or by cups from the
cranium, and ice bags or cold water may be applied to the head. Hot foot
baths or mustard embrocations applied to the limbs, and even derivation
toward the bowels may be used. The indications for treatment come to be
for meningo-encephalitis.