Spinal caries in old horses, sprains, fractures, infections; caries
often confined to articulating processes: anatomical form:
Axoido-atloid caries from poll evil, concussions, fights, rachitis.
Tubercle of bone and intervertebral cartilage in cattle. Symptoms:
distortion, stiffness, rigidity; stands day and night, sensory and
motor paralysis: localization of lesion; dyspnœa; spastic palsy back
of lesion; effect on tail, sphincters. Diagnosis: progressive
tenderness and stiffness of spine, distortion, localized exaltation or
depression of nervous function, osteoporosis, rachitis, caries,
tubercle, melanoma, abscess, infectious disease. Treatment: Sling in
narrow stall, good food, pure air, sunshine, tonics, phosphates.
As seen in the human subject spinal caries is usually tubercular and is
known as “_Pott’s disease_.” As seen in old horses it appears to be
rather a result of other infections, especially purulent, and may have
started in connection with traumatic or mechanical injuries to the bones
and ligaments. In such cases I have seen it repeatedly in hollow backed
horses in which the line of the spine descended abruptly and extremely
from the withers and rose again to the sacrum. The distortion was so
great that the back appeared as if it could barely sustain the weight of
the animal and yet the patients were kept at work and proved useful for
light driving. Post mortem examination showed extensive caries and
suppuration of the vertebral bodies, confined, however, to one or two
segments as if due to a mechanical lesion. In the region of the loins it
is much more likely to affect the articulations of the vertebral rings,
because of the manner in which these are wedged into each other when the
spine is pressed downward. In the neck where the normal movement is so
much freer such injuries are much less common. Caries affecting the
articular surfaces of the axoido—atloid joint is by no means uncommon.
It may follow poll evil, or injuries sustained when a horse runs against
a wall, or in the fights of bulls or rams. Disease of the vertebræ may
be of the nature of rachitis occurring in this case in early life.
In cattle the disease is liable to be tubercular in which case, not only
is the bone invaded but the morbid process extends to the intervertebral
cartilage and projecting, presses on the spinal meninges and cord. It
may even encircle the entire spinal cavity and strangle the cord. If the
pus should extend downward it may form abscess under the spine, and
rupture into an internal cavity or externally.
_Symptoms._ Injuries and disease of the vertebræ may last for a length
of time without implicating the spinal cord or nerves. They may then
cause only distortion, with stiffness or rigidity of the spinal column.
When, however, the displacement of the injured, carious or tubercular
bones, the distension of the abscess or the increase of the hyperplasia
leads to pressure on the nerve roots, the meninges or cord, nervous
symptoms are likely to be developed. Compression of the nerve
roots—sensory or motor—may cause sensory or motor paralysis or both,
limited to particular areas the outline of which will point to the
precise seat of the lesion. If in the recti of the head and other
muscles of the neck, it points to the anterior cervical vertebræ. If in
the fore limbs, it points to the posterior bones of the neck. The
implication of the diaphragm would incriminate the fourth and fifth
cervical vertebræ. If in the crural muscles or those of the quarter and
thigh, the lumbar vertebræ must be looked to. The implication of the
nerves of the back, while impairing the functions of the intercostal and
abdominal muscles, produce less marked symptoms than when the limbs are
involved.
When the disease extends deeper so as to implicate the meninges and
especially the cord, there is evidence of impairment or interruption of
conduction in the cord in addition to the simple involving of the nerves
that emerge at that point. Thus serious disease or pressure on the
cervical part of the cord in front of the fourth vertebra will make
respiration difficult or impossible and speedy asphyxia may ensue. The
paralysis of all parts behind the lesion is overlooked, in view of the
fatal nature of the paralysis of the intercostals and diaphragm. If the
interruption of conduction is incomplete there may be spastic paralysis
and hyperæsthesia in the limbs and trunk back of the lesion.
If the dorsal cord is involved so as to render conduction imperfect
there will be at first imperfect control of parts posterior to the
lesion, and when still further implicated, flaccid or spastic paralysis,
especially of the hind limbs and tail. When it implicates the lumbar
region in addition to the paralysis named for the dorsal, there will be
incontinence of urine and even relaxation of the anal sphincter. In a
case of acute tuberculosis in a cow, supervening on an ancient
tuberculous lesion, as seen by the author, there were imperfect control
of the hind limbs and uncertain gait, with tenderness of the dorsal
region as if the animal had sprain of the back.
_Diagnosis_ of these cases of vertebral disease may not always be
possible in the early stages, yet the symptoms of progressive tenderness
and stiffness in the region of the spine, the distortion in some
instances of the spinal column, the subsequent appearance of localized
motor and sensory symptoms, and later still the spasms or spastic
paralysis in all parts behind the seat of the lesion, will be strongly
suggestive of such a disease. When indications exist of osteoporosis,
rachitis, or tuberculosis, of caries, abscess, or infectious lesions of
the cervical or dorsal spinal region, the inference is still stronger.
Then if reaction occurs under the tuberculin test, or if the urine
contains an excess of phosphates in the herbivora, the case may be
diagnosed with certainty.
_Treatment._ This will rarely be admissible on account of the expense
and uncertainty of result. Some meat animals may be killed for food. If
otherwise, keep in narrow stall where the animal cannot turn even the
head, feed from moderate level to avoid movement of the spine by the
upward and downward movements of the head. Gentle brushing is useful as
a means of cleanliness, and of toning up the muscular system. Nourishing
food of an easily digestible kind is essential, and pure air and
sunshine are important auxiliaries. A course of cod liver oil with
bitters may be given to improve the general health, calcium sulphide may
be tried in case of suppurative caries, and calcium phosphate will
usually be desirable to improve the nutrition and consistency of the
osseus system. In case of a valued patient which it is desirable to
preserve for reasons of sentiment or affection, or for breeding
purposes, one might be warranted in continuing a long and expensive
course of treatment, but in the regular run of cases considerations of
humanity and economy would counsel the prompt destruction of the animal.