membranes or cerebral masses, it is the pressure from the distended and
engorged blood vessels and the rapid accumulation of inflammatory
products that endangers the life of the animal in even the very early
stage of the disease. The earlier the treatment is commenced to lessen
the danger of fatal pressure from the engorged blood vessels, the less
effusion and smaller number of inflammatory products we have to contend
with later. The leading object, then, to be accomplished in the
treatment of the first stage of encephalitis, meningitis, or cerebritis,
and before a dangerous degree of effusion or exudation has taken place,
is to relieve the engorgement of the blood vessels and thereby lessen
the irritation or excitability of the affected structures. If the
attempt to relieve the engorgement in the first stage has been only
partially successful, and the second stage, with its inflammatory
products and exudations, whether serous or plastic, has set in, then the
main objects in further treatment are to keep up the strength of the
animal and hasten the absorption of the exudative products as much as
possible. To obtain these results, when the animal is found in the
initial stage of the disease, if there is unnatural excitability or
stupor with increase of temperature and quickened pulse, we should apply
cold to the head in the form of cold water or ice. For this purpose
cloths or bags may be used, and they should be renewed as often as
necessary. If the disease is still in its early stages and the animal is
strong, bleeding from the jugular vein may be beneficial. Good results
are to be expected only during the stage of excitement, while there is a
strong, full pulse and the mucous membranes of the head are red from a
plentiful supply of blood. The finger should be kept on the pulse and
the blood allowed to flow until there is distinct softening of the
pulse. As soon as the animal recovers somewhat from the shock of the
bleeding the following medicine should be made into a ball or dissolved
in a pint of warm water and be given at one dose: Barbados aloes, 7
drams; calomel, 2 drams; powdered ginger, 1 dram; tincture of aconite,
20 drops.
The animal should be placed in a cool, dark place, as free from noise as
possible. When the animal becomes thirsty half an ounce of bromid of
potash may be dissolved in the drinking water every six hours.
Injections of warm water into the rectum may facilitate the action of
the purgative. Norwood's tincture of veratrum viride, in 20-drop doses,
should be given every hour and 1 dram of solid extract of belladonna
every four hours until the symptoms become modified and the pulse
regular and full.
[Illustration: PLATE XIX.
THE NERVOUS SYSTEM.]
If this treatment fails to give relief, the disease will pass into the
advanced stages, or, if the animal has been neglected in the early
stages, the treatment must be supplanted with the hypodermic injection
of ergotin, in 5-grain doses, dissolved in 1 dram of water, every six
hours. The limbs may be poulticed above the fetlocks with mustard. Warm
blanketing, to promote perspiration, is to be observed always when there
is no excessive perspiration.
If the disease becomes chronic (encephalitis or meningitis), we must
place our reliance upon alteratives and tonics, with such incidental
treatment as special symptoms may demand. Iodid of potassium in 2-dram
doses should be given three times a day and 1 dram of calomel once a day
to induce absorption of effusions or thickened membranes. Tonics, in the
form of iodid of iron in 1-dram doses, to which is added 2 drams of
powdered hydrastis, may also be given every six or eight hours, as soon
as the active fever has abated. After the disappearance of the acute
symptoms, blisters (cantharides ointment) may be applied behind the
poll. When paralytic effects remain after the disappearance of all other
symptoms, sulphate of strychnia in 2-grain doses, in combination with
the other tonics, may be given twice a day and be continued until it
produces muscular twitching. In some cases of paralysis, as of the lips
or throat, benefit may be derived from the moderate use of the electric
battery. Many of the recoveries will, however, under the most active and
early treatment, be but partial, and in all cases the animals become
predisposed to subsequent attacks. A long time should be allowed to pass
before the animal is exposed to severe work or great heat. When the
disease depends upon mechanical injuries, they have to be treated and
all causes of irritation to the brain removed. If it is due to stable
miasma, uremic poisoning, pyemia, influenza, rheumatism, toxic agents,
etc., they should receive prompt attention for their removal or
mitigation.
Cerebral softening, abscess, and sclerosis are practically inaccessible
to treatment, otherwise than such relief as may be afforded by the
administration of opiates and general tonics, and, in fact, the
diagnosis is largely presumptive.
CONGESTION OF THE BRAIN, OR MEGRIMS.
Congestion of the brain consists in an accumulation of blood in the
vessels, also called hyperemia, or engorgement. It may be active or
passive--active when there is an undue accumulation of blood or
diminished arterial resistance, and passive when it accumulates in the
vessels of the brain, owing to some obstacle to its return by the veins.
_Causes._--Active cerebral congestion may be from hypertrophy of the
left ventricle of the heart, excessive exertion, the influence of
extreme heat, sudden and great excitement, artificial stimulants, etc.
Passive congestion may be produced by any mechanical obstruction which
prevents the proper return of blood through the veins to the heart, such
as a small or ill-fitting collar, which often impedes the blood current,
tumors or abscesses pressing on the vein in its course, and organic
lesions of the heart with regurgitation.
Extremely fat animals with short, thick necks are peculiarly subject to
attacks of cerebral congestion. Simple congestion, however, is merely a
functional affection, and in a slight or moderate degree involves no
immediate danger. Extreme engorgement, on the contrary, may be followed
by rupture of previously weakened arteries and capillaries and cause
immediate death, designated then as a stroke of apoplexy.
_Symptoms._--Congestion of the brain is usually sudden in its
manifestation and of short duration. The animal may stop very suddenly
and shake its head or stand quietly braced, then stagger, make a plunge,
and fall. The eyes are staring, breathing hurried and stertorous, and
the nostrils widely dilated. This may be followed by coma, violent
convulsive movements, and death. Generally, however, the animal gains
relief in a short time, but may remain weak and giddy for several days.
If it is due to organic change of the heart or the disease of the blood
vessels in the brain, then the symptoms may be of slow development,
manifested by drowsiness, dimness or imperfect vision, difficulty in
voluntary movements, diminished sensibility of the skin, loss of
consciousness, delirium, and death. In milder cases effusion may take
place in the arachnoid spaces and ventricles of the brain, followed by
paralysis and other complications.
_Pathology._--In congestion of the brain the cerebral vessels are loaded
with blood, the venous sinuses distended to an extreme degree, and the
pressure exerted upon the brain constitutes actual compression, giving
rise to the symptoms just mentioned. On post-mortem examinations this
engorgement is found universal throughout the brain and its membranes,
which serves to distinguish it from inflammations of these structures,
in which the engorgements are confined more or less to circumscribed
portions. A prolonged congestion may, however, lead to active
inflammation, and in that case we find serous and plastic exudations in
the cavities of the brain. In addition to the intensely engorged
condition of the vessels we find the gray matter of the brain redder
than natural. In cases in which several attacks have occurred the blood
vessels are often found permanently dilated.
_Treatment._--The animal should be taken out of harness at once, with
prompt removal of all mechanical obstructions to the circulation. If it
is caused by venous obstruction by too tight a collar, the loosening of
the collar will give immediate relief. The horse should be bled freely
from the jugular vein. If due to tumors or abscesses, a surgical
operation becomes necessary to afford relief. To revive the animal if it
becomes partially or totally unconscious, cold water should be dashed on
the head. Give a purge of Glauber's salt. If the limbs are cold,
tincture of capsicum or strong mustard water should be applied to them.
If symptoms of paralysis remain after two or three days, an active
cathartic and iodid of potassium will be indicated, to be given as
prescribed for inflammation of the brain. In confirmed cases, treatment
is not advisable, as there is considerable danger to the owner should an
attack occur in a crowded street.
_Prevention._--Well-adjusted collar, with strap running from the collar
to the girth, to hold down the collar when pulling upgrade; regular feed
and exercise, without allowing the animal to become excessively
plethoric; moderate checking, allowing a free-and-easy movement of the
head; well-ventilated stabling, proper cleanliness, pure water, etc.
SUNSTROKE, HEAT STROKE, OR HEAT EXHAUSTION.
The term sunstroke is applied to affections occasioned not exclusively
by exposure to the sun's rays, as the word signifies, but by the action
of great heat combined generally with humid atmosphere. Exhaustion
produced by long-continued heat is often the essential factor, and is
called heat exhaustion. Horses on the race track undergoing protracted
and severe work in hot weather often succumb to heat exhaustion. Draft
horses which do not receive proper care in watering, feeding, and rest
in shady places and are exposed for many hours to the direct rays of the
sun suffer very frequently from sunstroke.
_Symptoms._--Sunstroke is manifested suddenly. The animal stops, drops
his head, begins to stagger, and soon falls to the ground unconscious.
The breathing is marked with great stertor, the pulse is very slow and
irregular, cold sweats break out in patches on the surface of the body,
and the animal often dies without having recovered consciousness.
The temperature becomes very high, reaching 105 deg. to 109 deg. F.
In heat exhaustion the animal usually requires urging for some time
prior to the appearance of any other symptoms, generally perspiration is
checked, and then the horse becomes weak in its gait, the breathing
hurried or panting, eyes watery or bloodshot, nostrils dilated and
highly reddened, assuming a dark, purple color; the pulse is rapid and
weak, the heart bounding, followed by unconsciousness and death. If
recovery takes place, convalescence extends over a long period of time,
during which incoordination of movement may persist.
_Pathology._--Sunstroke, virtually active congestion of the brain, often
accompanied with effusion and blood extravasation, characterizes this
condition, with often rapid and fatal lowering of all the vital
functions. In many instances the death may be due to the complete
stagnation in the circulation of the brain, inducing anemia, or want of
nourishment of that organ. In other cases it may be directly due to the
excessive compression of the nerve matter controlling the heart's
action, and cause paralysis of that organ. There are also changes in the
composition of the blood.
_Treatment._--The animal should be placed in shaded surroundings. Under
no circumstances is blood-letting permissible in sunstroke. Ice or very
cold water should be applied to the head and along the spine, and half
an ounce of carbonate of ammonia or 6 ounces of whisky should be given
in 1 pint of water. Cold water may be used as an enema and should also
be showered upon the body of the horse from the hose or otherwise. This
should be continued until the temperature is down to 103 deg. F. Brisk
friction of the limbs and the application of spirits of camphor often
yields good results. The administration of the stimulants should be
repeated in one hour if the pulse has not become stronger and slower. In
either case, when reaction has occurred, preparations of iron and
general tonics may be given during convalescence: Sulphate of iron, 1
dram; gentian, 3 drams; red cinchona bark, 2 drams; mix and give in feed
morning and evening.
_Prevention._--In very hot weather horses should have wet sponges or
light sunshades on the head when at work, or the head may be sponged
with cold water as many times a day as possible. Proper attention should
be given to feeding and watering, never in excess. During the warm
months all stables should be cool and well ventilated, and if an animal
is debilitated from exhaustive work or disease it should receive such
treatment as will tend to build up the system. Horses should be
permitted to drink as much water as they want while they are at work
during hot weather.
An animal which has been affected with sunstroke is very liable to have
subsequent attacks when exposed to the necessary exciting causes.
APOPLEXY OR CEREBRAL HEMORRHAGE.
Apoplexy is often confounded with cerebral congestion, but true apoplexy
always consists in rupture of cerebral blood vessels, with blood
extravasation and formation of blood clot.
_Causes._--Two causes are involved in the production of apoplexy, the
predisposing and the exciting. The predisposing cause is degeneration,
or disease which weakens the blood vessel; the exciting cause is any one
which tends to induce cerebral congestion.
_Symptoms._--Apoplexy is characterized by a sudden loss of sensation and
motion, profound coma, and stertorous, difficult breathing. The action
of the heart is little disturbed at first, but soon becomes slower, then
quicker and feebler, and after a little time ceases. If the rupture is
one of a small artery and the extravasation limited, sudden paralysis of
some part of the body is the result. The extent and location of the
paralysis depend upon the location within the brain which is
functionally deranged by the pressure of the extravasated blood; hence
these conditions are very variable.
In the absence of any premonitory symptoms or an increase of temperature
in the early stage of the attack, we may be reasonably certain in making
the distinction between this disease and congestion of the brain, or
sunstroke.
_Pathology._--In apoplexy there is generally found an atheromatous
condition of the cerebral vessels, with weakening and degeneration of
their walls. When a large artery has been ruptured it is usually
followed by immediate death, and large rents may be found in the
cerebrum, with great destruction of brain tissue, induced by the
forcible pressure of the liberated blood. In small extravasations
producing local paralysis without marked general disturbance the animal
may recover after a time; in such cases gradual absorption of the clot
takes place. In large clots atrophy of the brain substances may follow,
or softening and abscess from want of nutrition may result, and render
the animal worthless, ultimately resulting in death.
_Treatment._--Place the animal in a quiet, cool place and avoid all
stimulating feed. Administer, in the drinking water or feed, 2 drams of
the iodid of potassium twice a day for several weeks if necessary.
Medical interference with sedatives or stimulants is more liable to be
harmful than of benefit, and blood-letting in an apoplectic fit is
extremely hazardous. From the fact that cerebral apoplexy is due to
diseased or weakened blood vessels, the animal remains subject to
subsequent attacks. For this reason treatment is very unsatisfactory.
COMPRESSION OF THE BRAIN.
_Causes._--In injuries from direct violence a piece of broken bone may
press upon the brain, and, according to its size, the brain is robbed of
its normal space within the cranium. It may also be due to an
extravasation of blood or to exudation in the subdural or arachnoid
spaces. Death from active cerebral congestion results through
compression. The occurrence may sometimes be traced to the direct cause,
which will give assurance for the correct diagnosis.
_Symptoms._--Impairment of all the special senses and localized
paralysis. All the symptoms of lessened functional activity of the brain
are manifested to some degree. The paralysis remains to be our guide
for the location of the cause, for it will be found that the paralysis
occurs on the opposite side of the body from the location of the injury,
and the parts suffering paralysis will denote, to an expert veterinarian
or physician, the part of the brain which is suffering compression.
_Treatment._--Trephining, by a skillful operator, for the removal of the
cause when due to depressed bone or the presence of foreign bodies. When
the symptoms of compression follow other acute diseases of the brain,
apoplectic fits, etc., the treatment must be such as the exigencies of
the case demands.
CONCUSSION OF THE BRAIN.
This is generally caused by falling over backward and striking the poll,
or perhaps falling forward on the nose, by a blow on the head, etc.
Train accidents during shipping often cause concussion of the brain.
_Symptoms._--Concussion of the brain is characterized by giddiness,
stupor, insensibility, or loss of muscular power, succeeding immediately
upon a blow or severe injury involving the cranium. The animal may rally
quickly or not for hours; death may occur on the spot or after a few
days. When there is only slight concussion or stunning, the animal soon
recovers from the shock. When more severe, insensibility may be complete
and continue for a considerable time; the animal lies as if in a deep
sleep; the pupils are insensible to light; the pulse fluttering or
feeble; the surface of the body cold, muscles relaxed, and the breathing
scarcely perceptible. After a variable interval partial recovery may
take place, which is marked by paralysis of some parts of the body,
often of a limb, the lips, ear, etc. Convalescence is usually tedious,
and frequently permanent impairment of some organs remains.
_Pathology._--Concussion produces laceration of the brain, or at least a
jarring of the nervous elements, which, if not sufficiently severe to
produce sudden death, may lead to softening or inflammation, with their
respective symptoms of functional derangement.
_Treatment._--The first object in treatment will be to establish
reaction or to arouse the feeble and weakening heart. This can often be
accomplished by dashing cold water on the head and body of the animal;
frequent injections of weak ammonia water, ginger tea, or oil and
turpentine should be given per rectum. In the majority of cases this
will soon bring the horse to a state of consciousness. In more severe
cases mustard poultices should be applied along the spine and above the
fetlocks. As soon as the animal gains partial consciousness stimulants,
in the form of whisky or capsicum tea, should be given. Owing to
severity of the structural injury to the brain or the possible rupture
of blood vessels and blood extravasation, the reaction may often be
followed by encephalitis or cerebritis, and will then have to be treated
accordingly. For this reason the stimulants should not be administered
too freely, and they must be abandoned as soon as reaction is
established. There is no need for further treatment unless complications
develop as a secondary result. Bleeding, which is so often practiced,
proves almost invariably fatal in this form of brain affection. We
should also remember that it is never safe to drench a horse with large
quantities of medicine when he is unconscious, for he is very liable to
draw the medicine into the lungs in inspiration.
_Prevention._--Young horses, when harnessed or bitted for the first few
times, should not have their heads checked high, for it frequently
causes them to rear up, and, being unable to control their balance, they
are liable to fall over sideways or backwards, thus causing brain
concussion when they strike the ground.
ANEMIA OF THE BRAIN.
This is a physiological condition in sleep. It is considered a disease
or may give rise to disease when the circulation and blood supply of the
brain are interfered with. In some diseases of the heart the brain
becomes anemic, and fainting fits occur, with temporary loss of
consciousness. Tumors growing within the cranium may press upon one or
more arteries and stop the supply of blood to certain parts of the
brain, thus inducing anemia, ultimately atrophy, softening, or
suppuration. Probably the most frequent cause is found in plugging, or
occlusion, of the arteries by a blood clot.
_Symptoms._--Imperfect vision, constantly dilated pupils, frequently a
feeble and staggering gait, and occasionally cramps, convulsions, or
epileptic fits occur.
_Pathology._--The exact opposite of cerebral hyperemia. The blood
vessels are found empty, the membranes blanched, and the brain substance
softened.
_Treatment._--Removal of the remote cause when possible. General tonics,
nutritious feed, rest, and removal from all causes of nervous
excitement.
HYDROCEPHALUS, OR DROPSY OF THE BRAIN.
This condition consists in an unnatural collection of fluid about or in
the brain. Depending upon the location of the fluid, we speak of
external and internal hydrocephalus.
External hydrocephalus is seen chiefly in young animals. It consists in
a collection of fluid under the meninges, but outside the brain proper.
This defect is usually congenital. It is accompanied with an
enlargement of the skull, especially in the region of the forehead. The
pressure of the fluid may cause the bones to soften. The disease is
incurable and usually fatal.
Internal hydrocephalus is a disease of mature horses, and consists in
the accumulation of an excessive quantity of fluid in the cavities or
ventricles of the cerebrum. The cause of this accumulation may be a
previous inflammation, a defect in the circulation of blood through the
brain, heat stroke, overwork, excessive nutrition, or long-continued
indigestion. Common, heavy-headed draft horses are predisposed to this
condition.
_Symptoms._--The symptoms are an expression of dullness and stupidity,
and from their nature this disease is sometimes known as "dumminess" or
"immobility." A horse so afflicted is called a "dummy." Among the
symptoms are loss of intelligence, stupid expression, poor memory, etc.
The appetite is irregular; the horse may stop chewing with a wisp of hay
protruding from his lips; he seems to forget that it is there. Unnatural
positions are sometimes assumed, the legs being placed in clumsy and
unusual attitudes. Such horses are difficult to drive, as they do not
respond readily to the word, to pressure of the bit, or to the whip.
Gradually the pulse becomes weaker, respiration becomes faster, and the
subject loses weight. Occasionally there are periods of great excitement
due to temporary congestion of the brain. At such times the horse
becomes quite uncontrollable. A horse so afflicted is said to have
"staggers." The outlook for recovery is not good.
Treatment is merely palliative. Regular work or exercise and nutritious
feed easy of digestion, with plenty of fresh water, are strongly
indicated. Intensive feeding should not be practiced. The bowels should
be kept open by the use of appropriate diet or by the use of small
regular doses of Glauber's salt.
TUMORS WITHIN THE CRANIUM.
Tumors within the cranial cavity and the brain occur not infrequently,
and give rise to a variety of symptoms, imperfect control of voluntary
movement, local paralysis, epilepsy, etc. Among the more common tumors
are the following:
Osseous tumors, growing from the walls of the cranium, are not very
uncommon.
Dentigerous cysts, containing a formation identical to that of a tooth,
growing from the temporal bone, sometimes are found lying loose within
the cranium.
Tumors of the choroid plexus, known as brain sand, are frequently met
with on post-mortem examinations, but seldom give rise to any
appreciable symptoms during life. They are found in horses at all ages,
and are slow of development. They are found in one or both of the
lateral ventricles, enveloped in the folds of the choroid plexus.