the cord, but generally it is more intense in some places than others;
when due to mechanical injury, the inflammation may remain confined to a
small section. The cord is swollen and congested, reddened, often
softened and infiltrated with pus cells, and the nerve elements are
degenerated.
_Treatment._--Similar to that of spinal meningitis.
SPINAL CONGESTION.
This condition consists in an excess of blood. As the blood vessels of
the pia mater are the principal source of supply to the spinal cord,
hyperemia of the cord and of the meninges usually go together. The
symptoms are, therefore, closely allied to those of spinal meningitis
and congestion. When the pia mater is diseased, the spinal cord is
almost invariably affected also.
_Cause._--Sudden checking of the perspiration, violent exercise, blows,
and falls.
_Symptoms._--The symptoms may vary somewhat with each case, and closely
resemble the first symptoms of spinal meningitis, spinal tumors, and
myelitis. First, some disturbance in movement, lowering the temperature,
and partial loss of sensibility posterior to the seat of the congestion.
If in the cervical region, it may cause interference in breathing and
the action of the heart. When in the region of the loins, there may be
loss of control of the bladder. When the congestion is sufficient to
produce compression of the cord, paraplegia may be complete. Usually
fever, spasms, muscular twitching, or muscular rigidity are absent,
which will serve to distinguish spinal congestion from spinal
meningitis.
_Treatment._--Hot-water applications to the spine, 1-dram doses fluid
extract of belladonna repeated every four hours, and tincture of aconite
root 20 drops every hour until the symptoms become ameliorated. If no
inflammatory products occur, the animal is likely to recover.
SPINAL ANEMIA.
This may be caused by extreme cold, exhausting diseases, spinal embolism
or plugging of a spinal blood vessel, an interference with the
circulation through the abdominal aorta, from compression, thrombosis,
or aneurism of that vessel; the spinal vessels may be caused to contract
through vasomotor influence, a result of peripheral irritation of some
nerve.
Spinal anemia causes paralysis of the muscles used in extending the
limbs. When the bladder is affected, it precedes the weakness of motion,
while in spinal congestion it follows, and increased sensibility, in
place of diminished sensibility, as in spinal congestion, is observed.
Pressure along the spine causes excessive pain.
If the exciting cause can be removed, the animal recovers; if this
fails, the spinal cord may undergo softening.
SPINAL COMPRESSION.
When caused by tumors or otherwise, when pressure is slight, it produces
a paralysis of the muscles used in extending a limb and contraction of
those which flex it. When compression is great it causes complete loss
of sensibility and motion posterior to the compressed part of the cord.
Compression of a lateral half of the cord produces motor paralysis,
disturbance of the circulation, and difficulty of movement, an increased
sensibility on the side corresponding to the compressed section, and a
diminished sensibility and some paralysis on the opposite side.
_Treatment._--When it occurs as a sequence of a preceding inflammatory
disease, iodid of potassium and general tonics are indicated. When due
to tumors growing within the spinal canal, or to pressure from displaced
bone, no form of treatment will result in any benefit.
SPINAL HEMORRHAGE.
This may occur from changes in the wall of the blood vessels, in
connection with tumors, acute myelitis, traumatic injuries, etc. The
blood may escape through the pia mater into the subarachnoid cavity, and
large clots be formed.
_Symptoms._--The symptoms are largely dependent upon the seat and extent
of the hemorrhage, as they are principally owing to the compression of
the cord. A large clot may produce sudden paraplegia, accompanied with
severe pain along the spine; usually, however, the paralysis of both
motion and sensation is not very marked at first; on the second or third
day fever is liable to appear, and increased or diminished sensibility
along the spine posterior to the seat of the clot. When the bladder and
rectum are involved in the symptoms it indicates that the spinal cord is
compressed.
_Treatment._--In the occurrence of injuries to the back of a horse,
whenever there is any evidence of paralysis, it is always advisable to
apply bags of ice along the spine to check or prevent hemorrhage or
congestion, and 2 drams of the fluid extract of ergot and 20 drops of
tincture of digitalis may be given every hour until three doses have
been taken. Subsequently tincture of belladonna in half-ounce doses may
be given three times a day. If there is much pain, 5 grains of sulphate
of morphia, injected under the skin, will afford relief and lessen the
excitability of the animal. In all cases the animal should be kept
perfectly quiet.
SPINAL CONCUSSION.
This is rarely observed in the horse, and unless it is sufficiently
severe to produce well-marked symptoms it would not be suspected. It may
occur in saddle horses from jumping, or it may be produced by falling
over an embankment, or a violent fall upon the haunches may produce it.
Concussion may be followed by partial paralysis or spinal hemorrhage;
generally, however, it is confined to a jarring and some disturbance of
the nerve elements of the cord, and the paralytic effect which ensues
soon passes off. Treatment consists in rest until the animal has
completely recovered from the shock. If secondary effects follow from
hemorrhage or compression, they have to be treated as heretofore
directed.
SPINAL TUMORS.
Within the substance of the cord glioma or the mixed gliosarcomata are
found to be the most frequent, tumors may form from the meninges and the
vertebrae, being of a fibrous or bony nature, and affect the spinal cord
indirectly by compression. In the meninges we may find glioma, cancers,
and psammoma, fibromata; aneurisms of the spinal arteries have been
discovered in the spinal canal.
_Symptoms._--Tumors of the spinal canal cause symptoms of spinal
irritation or compression of the cord. The gradual and slow development
of symptoms of paralysis of one or both hind limbs or certain muscles
may lead to a suspicion of spinal tumors. The paralysis induced is
progressive, but not usually marked with atrophy of the muscles or
increased sensibility along the spine. When the tumor is within the
spinal cord itself all the symptoms of myelitis may be present.
_Treatment._--General tonics and 1-dram doses of nux vomica may be
given; iodid of iron or iodid of potassium in 1-dram doses, three times
a day in feed, may, in a very few cases, give some temporary benefit.
Usually the disease progresses steadily until it proves fatal.
NEURITIS, OR INFLAMMATION OF A NERVE.
This is caused by a bruise or wound of a nerve or by strangulation in a
ligature when the nerve is included in the ligation of an artery. The
changes in an inflamed nerve are an enlargement, reddening of the nerve
sheath, spots of extravasated blood, and sometimes an infiltration of
serum mixed with pus.
_Symptoms._--Acute pain of the parts supplied by the nerve and absence
of swelling or increased heat of the part.
_Treatment._--Hypodermic injections of from 3 to 5 grains of morphia to
relieve pain, hot fomentations, and rest. If it is due to an inclusion
of a ligature, the nerve should be divided above and below the ligature.
NEUROMA, OR TUMOR OF A NERVE.
Neuroma may be from enlargement of the end of a divided nerve or due to
fibrous degeneration of a nerve which has been bruised or wounded. Its
most frequent occurrence is found after the operation of neurotomy for
foot lameness, and it may appear after the lapse of months or even
years. Neuroma usually develops within the sheath of the nerve with or
without implicating the nerve fibers. It is oval, running lengthwise
with the direction of the nerve.
_Symptoms._--Pain of the affected limb or part is manifested, more
especially after resting a while, and when pressure is made upon the
tumor it causes extreme suffering.
_Treatment._--Excision of the tumor, including part of the nerve above
and below, and then treat it like any other simple wound.
INJURIES TO NERVES.
These may consist in wounding, bruising, laceration, stretching,
compression, etc. The symptoms which are produced will depend upon the
extent, seat, and character of the injury. Recovery may quickly take
place, or it may lead to neuritis, neuroma, or spinal or cerebral
irritation, which may result in tetanus, paralysis, and other serious
derangements. In all diseases, whether produced by some form of external
violence or intrinsic causes, the nerves are necessarily involved, and
sometimes it is to a primary injury of them that the principal fault in
movement or change of nutrition of a part is due. It is often difficult
or impossible to discover that an injury to a nerve has been inflicted,
but whenever this is possible it may enable us to remedy that which
otherwise would result in permanent evil. Treatment should consist in
relieving compression, in hot fomentations, the application of anodyne
liniments, excision of the injured part, and rest.
FORAGE POISONING, OR SO-CALLED CEREBROSPINAL MENINGITIS.
This disease prevails among horses in nearly all parts of the United
States. Its appearance in America is by no means of recent occurrence,
for the malady was reported by Large in 1847, by Michener in 1850, and
by Liautard in 1869 as appearing in both sporadic and enzootic form in
several of the Eastern States. Since then the disease has occurred
periodically in many States in all sections of the country, and has been
the subject of numerous investigations and publications by a number of
the leading men of the veterinary profession. It is prevalent with more
or less severity every year in certain parts of the United States, and
during the year 1912 the Bureau of Animal Industry received urgent
requests for help from Colorado, Georgia, Iowa, Kansas, Kentucky,
Louisiana, Maryland, Missouri, Nebraska, New Jersey, North Carolina,
Oregon, South Carolina, South Dakota, Virginia, and West Virginia. While
in 1912 the brunt of the disease seemed to fall on Kansas and Nebraska,
other States were also seriously afflicted. In previous years, for
instance in 1882, as well as in 1897, the horses of southeastern Texas
were reported to have died by the thousand, and in the following year
the horses of Iowa were said to have "died like rats." However, Kansas
seems to have had more than her share of this trouble, as a severe
outbreak that extended over almost the entire State occurred in 1891,
while in 1902 and again in 1906 the disease recurred with equal severity
in various portions of the State.
This condition consists in a poisoning and depression of the nervous
system from eating or drinking feed or water containing poison generated
by mold or bacteria. It has been shown to be owing to eating damaged
ensilage, corn, brewers' grains, oats, etc., or to drinking stagnant
pond water or water from a well contaminated by surface drainage. Horses
at pasture may contract the disease when the growth of grass is so
profuse that it mats together and the lower part dies and ferments or
becomes moldy.
In England a similar disease has been called "grass staggers," due to
eating rye grass when it is ripening or when it is cut and eaten while
it is heating and undergoing fermentation. In eastern Pennsylvania it
was formerly known by the name of "putrid sore throat" and "choking
distemper." A disease similar in many respects which is very prevalent
in Virgina, especially along the eastern border, is commonly known by
the name of "blind staggers," and in many of the Southern States this
has been attributed to the consumption of worm-eaten, corn. Horses of
all ages and mules are subject to this disease.
_Symptoms and lesions._--The symptoms which typify sporadic or epidemic
cerebrospinal meningitis in man are not witnessed among horses, namely,
excessive pain, high fever, and early muscular rigidity. In the
recognition of the severity of the attack we may divide the symptoms
into three grades. In the most rapidly fatal attacks the animal may
first indicate it by weak, staggering gait, partial or total inability
to swallow solids or liquids, impairment of eyesight; twitching of the
muscles and slight cramps may be observed. As a rule, the temperature is
not elevated--indeed, it is sometimes below normal. This is soon
followed by a paralysis of the whole body, inability to stand, delirium
in which the animal sometimes goes through a series of automatic
movements as if trotting or running; the delirium may become very
violent and the unconscious animal may bruise his head very seriously in
his struggles; but usually a deep coma renders him quiet until he
expires. Death in these cases usually takes place in from 4 to 24 hours
from the time the first symptoms become manifest. The pulse is variable
during the progress of the disease; it may be almost imperceptible at
times, and then again very rapid and irregular; the respirations
generally are quick and catching. In the next form in which this disease
may develop it first becomes manifest by a difficulty in swallowing and
slowness in mastication, and a weakness which may be first noticed in
the strength of the tail; the animal will be unable to switch it or to
offer resistance when we bend it up over the croup. The pulse is often a
little slower than normal. There is no evidence of pain; the
respirations are unchanged, and the temperature little less than normal;
the bowels may be somewhat constipated. These symptoms may remain
unchanged for two or three days and then gradual improvement may take
place, or the power to swallow may become entirely lost and the weakness
and uncertainty in gait more and more perceptible; then sleepiness or
coma may appear; the pulse becomes depressed, slow, and weak, the
breathing stertorous, and paroxysms of delirium develop, with inability
to stand, and some rigidity of the spinal muscles or partial cramp of
the neck and jaws. In such cases death may occur in from 6 to 10 days
from the commencement of the attack. In many cases there is no evidence
of pain, spasm, or fever at any time during the progress of the disease,
and finally profound coma develops and death follows, painless and
without a struggle.
In the last or mildest form the inability of voluntary control of the
limbs becomes but slightly marked, the power of swallowing never
entirely lost, and the animal has no fever, pain, or unconscious
movements. Generally the animal will begin to improve about the fourth
day and recovers.
In a few cases the spinal symptoms, manifested by paraplegia, may be the
most prominent symptoms; in others they may be altogether absent and the
main symptoms may be difficulty in mastication and swallowing; rarely it
may affect one limb only. In all cases in which coma remains absent for
six or seven days the animal is likely to recover. When changes toward
recovery take place, the symptoms usually leave in the reverse order to
that in which they developed, but local paralysis may remain for some
time, rarely persistent.
On post-mortem the number of lesions observable to the naked eye is in
marked contrast to the severity of the symptoms noted. The pharynx and
larynx are inflamed in many cases, and sometimes coated with a
yellowish-white glutinous deposit, extending at times over the tongue
and occasionally a little way down the trachea. The lungs are normal,
except from complications following drenching or recumbence for a long
period. The heart is usually normal in appearance, except an occasional
cluster of hemorrhagic points on the outer surface, while the blood is
dark and firmly coagulated. The lining of the stomach indicates a
subacute gastritis, while occasionally an erosion is noted. An edema is
observed in the submucosa of such cases. The first few inches of the
small intestines likewise may show slight inflammation in certain cases,
while in others it is quite severe; otherwise the digestive tract
appears normal, excluding the presence of varying numbers of bots,
_Strongylus vulgatus_, and a few other nematodes. The liver is congested
and swollen in some cases, while it appears normal in others. The spleen
is, as a rule, normal, and at times the kidneys are slightly congested.
The bladder is often distended with dark-colored urine, and occasionally
a marked cystitis has been observed. The adipose tissue throughout the
carcass may show a pronounced icteric appearance in certain cases. On
removing the bones of the skull the brain appears to be normal
macroscopically in a few instances, but in most cases the veins and
capillaries of the meninges of the cerebrum, cerebellum, and
occasionally the medulla is distinctly dilated and engorged, and in a
few cases there are pronounced lesions of a leptomeningitis. An
excessive quantity of cerebrospinal fluid is present in most of the
cases. On the floor of the lateral ventricles of several brains there
was noted a slight softening caused by hemorrhages into the brain
substance. There is always an abundance of fluid in the subarachnoid
spaces, ventricles, and at the base of the brain, usually of the color
of diabetic urine, and containing a limited number of flocculi, but in a
few cases it was slightly blood tinged. The spinal cord was not found
involved in the few cases examined.
_Treatment._--One attack of the disease does not confer immunity. Horses
have been observed which have recovered from two attacks, and still
others that recovered from the first but died as a result of the second
attack.
Inasmuch as a natural immunity does not appear after an attack of
cerebrospinal meningitis, it might be anticipated that serum of
recovered cases would possess neither curative nor prophylactic
qualities. Nevertheless, experiments have been made along these lines
with serum from recovered cases, but without any positive results.
Similar investigations have been conducted by others in Europe with
precisely the same results. With the tendency of the disease to produce
pathological lesions in the central nervous system, it seems scarcely
imaginable that a medicinal remedy will be found to heal these foci, and
even when recovery takes place considerable disturbance in the
functions, as blindness, partial paralysis, dumbness, etc., is liable to
remain. Indeed, when the disease once becomes established in an animal,
drugs seem to lose their physiological action. Therefore, with all the
previously mentioned facts before us, it is evident that the first
principle in the treatment of this disease is prevention, which consists
in the exercise of proper care in feeding only clean, well-cured forage
and grain and pure water. These measures when faithfully carried out
check the development of additional cases of the disease upon the
affected premises.
While medicinal treatment has proved unsatisfactory in most cases,
nevertheless the first indication is to clean out the digestive tract
thoroughly, and to accomplish this prompt measures must be used early in
the disease. Active and concentrated remedies should be given,
preferably subcutaneously or intravenously, owing to the great
difficulty in swallowing, even in the early stage. Arecolin in one-half
grain doses, subcutaneously, has given as much satisfaction as any other
drug. After purging the animal the treatment is mostly symptomatic.
Intestinal disinfectants, particularly calomel, salol, and salicylic
acid, have been recommended, and mild, antiseptic mouth washes are
advisable. Antipyretics are of doubtful value, as better results are
obtained, if the temperature is high, by copious cold-water injections.
An ice pack applied to the head is beneficial in case of marked psychic
disturbance. One-ounce doses of chloral hydrate per rectum should be
given if the patient is violent or if muscular spasms are severe. If the
temperature becomes subnormal, the animal should be warmly blanketed,
and if much weakness is shown this should be combated with stimulants,
such as strychnin, camphor, alcohol, atropin, or aromatic spirits of
ammonia. Early in the disease urotropin (hexamethylenamin) in doses of
25 grains, dissolved in water and given by the mouth every two hours,
appeared to have been responsible for the recovery of some cases of the
malady. During convalescence tonic treatment is indicated.
_Hygienic measures needful._--Whenever this disease appears in a stable
all the animals should be removed as soon as possible. They should be
provided with clean, well-ventilated, and well-drained stables, and each
animal should receive a laxative and be fed feed and given water from a
new, clean source. The abandoned stable should be thoroughly cleansed
from all waste matters, receive a coat of whitewash containing 4 ounces
of carbolic acid to the gallon of water and should have time to dry
thoroughly before the horses are replaced. A complete change of feed is
of the very greatest importance on account of the belief that the cause
resides in diseased grain, hay, and grass.
TETANUS, OR LOCKJAW.
This disease is characterized by spasms affecting the muscles of the
face, neck, body, and limbs and of all muscles supplied by the
cerebrospinal nerves. The spasms or muscular contractions are rigid and
persistent, yet mixed with occasional more intense contractions of
convulsive violence.
_Causes._--This disease is caused by a bacillus that is often found in
the soil, in manure, and in dust. This germ forms spores at the end of
the organism and grows only in the absence of oxygen. It produces a
powerful nerve poison, which causes the symptoms of tetanus. The germ
itself multiplies at the point where it is introduced, but its poison is
absorbed and is carried by the blood to all parts of the body, and thus
the nervous system is poisoned. Deep wounds infected by this germ are
more dangerous than superficial wounds, because in them the germ is more
remote from the oxygen of the air. Hence, nail pricks, etc., are
especially dangerous. In the majority of instances the cause of tetanus
can be traced to wounds, especially pricks and wounds of the feet or of
tendinous structures. It sometimes follows castration, docking, the
introduction of setons, inclusion of a nerve in a ligature, etc. It may
come on a long time after the wound is healed--three or four months.
Horses with a nervous, excitable disposition are more predisposed than
those of a more sluggish nature. Stallions are more subject to develop
tetanus as the result of wounds than geldings, and geldings more than
mares.