Part 32

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.

SLOW COMPRESSION OF SPINAL CORD. PARALYSIS.

Causes: Caries, vertebral diseases and lesions, neoplasms, actinomycosis, tubercle, abscess, organizing exudates, parasites. Melanoma, cholesteatoma, sarcoma, papilloma, lipoma, glioma, chrondroma. Symptoms: advance insensibly, or by sudden leap with exudate, spasm, paresis, transverse, senses clear, muscular atrophy, advance from behind forward. Cervical, dorsal, lumbar lesions. Bladder, sphincters, tail. Symptoms increased by movement. Treatment: according to lesion. Tumors, hopeless. Blood clots, Actinomycosis. Analgesics. Electricity.

Causes. Slowly progressive compression of the cord has been already noted as resulting from caries and other diseases of the vertebræ. It remains to notice such as result from the growth of tumors and other neoplasms in the spinal canal. In the horse these are commonly melanoma (in white horses), sarcoma, encephaloid, papilloma, cholesteatoma, and osteoma; in cattle, beside tubercle and actinomycosis, have been found sarcoma, lipoma, osteoma and glioma; and in dogs sarcoma and chondro-sarcoma. Chronic abscesses may be met with in all animals determining the same class of symptoms by slow pressure. In the same manner exudates in process of organization contract, and are liable to compress the myelon. Cadeac draws attention to a calcic degeneration of exudates in the dura mater of the dog (ossifying pachymeningitis), and of ossification of the intervertebræ cartilages with vegetations on their surfaces. Parasites also exercise a growing pressure, especially echinococcus, in cattle cysticercus mediocanellata, in sheep and dogs cœnurus, and in pigs and dogs cysticercus cellulosa.

=Melanoma.= In gray and white horses, with disseminated melanosis, the spinal canal is often involved, the pigmentary sarcoma appearing in small formations and sometimes large enough to determine injurious pressure. In the early stages these may cause stiffness and lameness referable to particular muscles or groups, varying in situation, even as to the limbs affected, at successive dates, and finally merging into paraplegia.

=Cholesteatoma= is less common than in the encephalon, yet one is reported by Dexler as attached to the pia mater and possessed of great firmness, crisply crackling under the knife. It doubtless secures accretions under meningeal exudates like those of the choroid plexus.

=Sarcoma= and =encephaloid= are usually found in connection with the dura mater, and of small size, but numerous. They often surround the roots of the spinal nerves, and here as on the cord exert sufficient pressure to impair nervous function.

=Papilloma= has been found connected with the pia mater and of marked vascularity. The author has found one in the ewe in a case of the neurasthenia of advanced gestation.

=Lipoma= is also rare. Osseous growths are common, being favored by sprains and injuries. All show a marked predilection for the lumbar and last dorsal vertebræ. This may be partly explained by the liability to injury and to disease invasion through the interlocking of the joint surfaces of the rings. Osteophytes growing from the intervertebral cartilage are common in the dorsal region as well.

=Glioma= has been found in cattle, occupying the substance of the cord itself and growing to the size of a hen’s egg or even of the closed fist. The cord is gradually atrophied and paraplegia is inevitable.

=Chrondro-sarcoma= has been found growing from the intervertebral fibro cartilage of dogs.

The Symptoms may be deferred for a length of time on account of the accommodation of the myelon to the slowly increasing pressure. When they do become manifest, it is usually at first by insensible gradations so that for a time their existence is questionable. Yet a case will sometimes reach a sudden climax, by reason of a blood extravasation or inflammatory exudate, and the signs of sudden pressure or acute myelitis or meningitis supervene. In the absence of sudden access of trouble, the symptoms are those of a slow increase of motor troubles (local paresis, paralysis, paraplegia), or sensory (hyperæsthesia, anæsthesia). Spasms may occur early or even later in the disease. From disorders due to cerebral lesions the morbid phenomena are distinguished by being paraplegic rather than hemiplegic; sensori-motor rather than sensory or motor; local rather than general; with intelligence and special senses clear, rather than dull or abolished; associated with marked muscular atrophy in the affected parts; advancing from behind forward rather than uniform throughout the body.

The area of nervous disorder points more or less clearly to the seat of the lesion. Early implication of the fore limbs, and then later of the hind, suggests lesion of the cervical region. Dyspnœa tumultuous heart action, or vertigo may coincide. Tardy movements of the hind limbs, imperfect balancing, dragging, swaying, knuckling, involuntary flexions of stifle or hock, flexor contractions, standing on toe, cramps, paraplegia, indicate lesion in the dorsal or lumbar region. There may be palsy of the rectum, anus, bladder, sphincter vesicæ, penis, and vulva. Paralysis or other nervous disorder of the tail and sphincters ani and vesicæ, without implication of the hind limbs or quarters, may bespeak lesion in the terminal end of the spinal cord.

With paralysis of the bladder the penis may be pendent out of the sheath, or being retained within it, the urine may dribble constantly into and from that cavity, and the vulva may be soft and flaccid. When the anus is involved, the adjacent part of the rectum usually participates becoming overloaded, the sphincter is soft and lax and allows a constant oozing, and the exposure of the mucosa. The paralytic tail hangs between the thighs, limp and flaccid, and becomes saturated with manure and in females with urine.

Even in the earlier stages the symptoms are usually greatly aggravated by compulsory movements like turning in a circle, walking up hill, or (in dogs) up a stair, the arched back, the pendent head, and hesitating planting of the foot suggests walking on pins. For a more exact localization of the lesion the reader may consult the table indicating the functions of the different parts of the spinal cord. The early fatigue under exercise grows as in other progressive spinal lesions.

Treatment. In most cases this is hopeless. Tumors, bony and calcic growths, tubercles, degenerations and absorption of nervous tissue are practically beyond remedy. A blood extravasation may be largely absorbed, leaving only the permanent changes in the nervous tissue. In this time is the main element. Actinomycosis may sometimes be successfully met by a course of potassium iodide, when, if the nervous lesions are slight, a fair recovery may be secured. In the majority of cases, however, the practitioner is limited to measures for palliation of suffering by atropia, chloral, phenacetin, etc., or by nerve stimulants like nux in small doses, or by weak currents of electricity. In meat producing animals, it is often the best course to fatten rapidly, or to turn over at once to the butcher.

DILATATION OF THE CENTRAL CANAL OF THE SPINAL CORD. SYRINGOMYELIA.

This means literally a cavity in the spinal cord but is applied to cavities formed by dilatation of the central spinal canal, or by an excavation in the nervous tissue immediately adjacent and usually communicating with a dilated segment of the canal. In man it is usually the result of an active proliferation of the epithelial cells of the canal, blocking the same, or extending into the adjacent nervous tissue in the form of a glioma. In different cases in dogs it occurred as the result of pressure. It has been seen in dogs, cats and Guinea pigs, as a casual lesion and as the result of experiment.

In a case reported by Lienaux it extended for practically the whole length of the cord, varying in form and size at different points. In the lumbar portion it was only slightly dilated, in the dorsal it was very irregular with prolongations into the gray matter, toward the cervical enlargement, its transverse section resembled an inverted V, and in the anterior cervical part it was unevenly rounded. Notable changes were cell proliferation and subsequent degeneration with the formation of cavities, thickening of the neuroglia, and compression and even obliteration of the vessels with circumscribed areas of necrosis, terminating also in cavity formation.

Symptoms. These vary with the nervous structures invaded, atrophied or destroyed. Invasion of the anterior horns of gray matter, causes trembling and muscular wasting. The implication of the superior horns determines more or less marked anæsthesia. Hyperæsthesia, spasms, paresis and paraplegia are also seen but no symptom nor group of symptoms is diagnostic of the exact lesion.

Treatment is manifestly hopeless.

NEURASTHENIA IN PREGNANT EWES.

Causes: inactivity, lowered muscular and nervous tone, twin pregnancy, approach of parturition, dry (clover hay) ration, concurrent diseases. Symptoms: moping, anorexia, depression, stupor, blindness, paresis, lethargy. Prevention: open air life, exercise, high muscular condition, avoidance of debilitating and relaxing conditions. Treatment: hygienic, nerve tonics, attend to concurrent diseases.

Neurasthenia has been defined as an incompetency of the nervous system, leading to early fatigue, and inability to recuperate from the prostrate condition. Pending a better knowledge of the affection, I have given this name to an asthenic affection seen in pregnant ewes when nearing the completion of the period of gestation.

Causes. In a large number of cases I have found several conditions so constant, not to say invariable, that they seem to deserve special attention in the list of causes: