Causes: Stimulating food to excess, sexual over-stimulation, violent
overexertion, hot sun, chill, rheumatism, traumas, injury to spinal
nerves, vertebral caries, microbian infection, narcotics, vegetable
poisons, cryptogams. Lesions: discoloration of white or gray matter,
swelling, friability, softening, extravasations in points, leucocytes
in excess, nerve cells cloudy, granular, nucleus enlarged, stain
highly, chromophile granules irregular, neuroglia thickened. Symptoms:
Hyperthermia, rigor, hyperæsthesia, tonic contractions in neck and
limbs, intense lameness, paresis, palsy, muscular atrophy, areas of
heat followed by coldness, such parts may not perspire, palsy less
complete than in broken back, circulation and breathing accelerated or
slow, paraplegia in large herbivora. Diagnosis: progressive onset,
hyperæsthesia or rigidity merging into palsy, retention and later
incontinence of urine, extreme spinal tenderness, rapid atrophy of
affected muscles, skin sloughing. Prognosis, always grave. Treatment:
purgation, bleeding, hot fomentations, ice bags, compresses,
derivatives, bromides, chloral, potassium iodide, atropia, ergot,
electricity, strychnia, soft laxative food, bitters, phosphates.
_Causes._ Like congestion this may be a result of =plethora= in overfed
animals, in those subjected to specially stimulating food like gluten
meal, cotton seed meal, beans, peas, vetches in excess, animal food for
herbivora (the waste of hotels and restaurants for cows, compressed meat
products for pigs), a period of absolute rest on full rations in horses
habituated to hard work and full feeding; of =sexual over-stimulation=
in males (stallion, bull, ram); of =violent overexertion=, especially if
=under a hot sun=; of =sudden chill= when over-fatigued and perspiring;
of =cold rain storms= (Freirier); of =rheumatism= (Kowalski); of
=traumatism= (fractures, sprains, slipping with overdistension); of
=falls upon the point of the ischium=; of blows upon the back (Cruzel,
Trasbot); of =tumors implicating the cord=; of =too violent efforts in
serving= by stallions; of =injuries of the great nerve trunks= passing
off from the cord (Gull, Trasbot, etc.); of extensions from =caries or
suppurations of the vertebræ= (Decoste, Trasbot); of =microbian
infection=, as in rabies, distemper, tubercle, dourine, louping ill,
milk sickness, contagious pneumonia, influenza, and suppurations; of
=narcotic poisoning=, as from ergot, smut, the poisons of the cryptogams
and bacteria of mouldy bread, musty fodder, spoiled meats, fish, etc.;
also the poisons of =lolium=, =vetch=, =lupin=, =astragalus=,
=oxytropis=, =arsenic=, etc.
_Lesions._ These consist in a yellow or pink discoloration of the white
and especially of the gray matter, and a special prominence of the
puncta vasculosa in the affected part. Swelling or distortion of the
part is not usual. This may involve only a single gray horn, the two
horns on the same side, the two inferior horns, or all four at once, or
the white matter adjacent may also show the rosy tint, the large puncta,
and a characteristic softness and friability. Minute blood
extravasations are very significant. Microscopically examined leucocytes
are found in abundance in the perivascular spaces and in the neuroglia.
The neurons (nerve ganglion cells) are degenerated, being cloudy,
swollen, with enlarged nucleus, stain highly, and show enlargement of
the chromophile granules. In a more advanced stage the cell has an
indefinite outline and the nucleus is indistinct and may fail to take a
stain; the chromophile granules are irregular and do not radiate evenly
from a centre and many vacuoles appear. This may lead to fatty
softening, or to fibrous increase of the neuroglia, and sclerosis.
_Symptoms._ These vary greatly in different cases according to the part
involved, the meninges or some special region of the cord, to the
essential cause of the inflammation and its acuteness. Usually the
attack sets in slowly in contradistinction to the abrupt attack of
congestion. =Hyperthermia= and =rigor= are usually among the first
symptoms, though in many cases =hyperæsthesia= is the most marked early
symptom. The skin covering the muscles which derive innervation from the
affected section of the cord is the most sensitive. This is often so
extreme along the vertebral column that percussion on the spinous
processes or pinching between the fingers and thumb causes the most
pronounced wincing and dropping of the back. Copland and Laposso have
noticed that a sponge of hot water drawn along the line of the vertebræ
causes acute pain and contractions of the muscles of the back and limbs,
which are almost tetanic in their force. This probably implies the
existence of meningitis, since the absence of rigidity of the muscles of
the neck, back and limbs, usually implies the absence of meningeal
inflammation. It may, however, occur in localized or commencing
myelitis. The existence of unilateral lesions and rigidity determines
intense lameness, which is further characterized by the most marked
hyperæsthesia.
The =morbid phenomena of the motor system= are more characteristically
paretic or paralytic than spasmodic. When rigidity or spasm ushers in
the attack it is superseded in a few hours or in two or three days by
flaccidity of the muscles of the affected part, with imperfect control
or even complete paralysis. The muscles affected will depend on the seat
of the spinal lesion. If in the neck it may affect fore and hind limbs,
and even the chest and abdomen; if in the back or loins it will induce
paraplegia, the anterior limit of which will correspond to the seat of
the lesion; if near the caudal extremity of the cord, (lumbar portion),
paralysis of the tail and of the sphincters ani and vesicæ may be
prominent features. Retention of urine and fæces (spasm) may precede
incontinence (palsy).
=Common sensation= may be dull or abolished on one or on both sides. If
on one side only, the other may show hyperæsthesia.
=Trophic modifications= are very marked though they may not be
noticeable at first. The paralytic muscles waste rapidly and the
impaired nutrition is manifested in the rapid formation of sloughing and
intractable sores where pressure comes in recumbency (the hips, stifles,
hocks, shoulders, etc.). This is especially noticeable on parts supplied
by the cord at or behind the seat of the lesions.
=Vaso-motor changes= are usually marked by a preliminary hyperthermia of
the affected parts, followed by a corresponding hypothermia. Sometimes
the affected part of the skin will remain quite dry while the rest of
the body is covered by perspiration.
=Choked optic disc= and retinitis are sometimes present.
The =febrile reaction= which is at first moderate, gradually increases
in force; the animals become dull, drowsy, careless of food, and the
hyperæsthesia merges into paresis or paralysis. This is rarely so
complete as in fracture of the vertebræ. If the inflammation is
restricted to the lower columns only, there may be akinesis without
change of the sensitiveness or with hypersensitiveness. If restricted to
the upper columns there may be sensory paralysis only on the opposite
side.
The =heart sounds and pulse= are usually altered, palpitations may
appear early with acceleration and sharpness of the pulse, and this may
alternate with a tardy slow pulse with intermissions. =Breathing= also
becomes accelerated and in violent cases with trembling, though in
moderate inflammation with effusion, softening and degeneration, it is
liable like the heart beats to become slow and tardy.
When =vertigo= appears it may be attributed to extension to the bulb or
cerebellum, or to the sympathetic implication of these organs.
The frequency with which paraplegia occurs in the large herbivora
suggests a special susceptibility of the lumbar portion of the cord,
probably in connection with severe muscular effort of the hind limbs.
In protracted cases the fever may run very high, being complicated by
septic poisoning from the numerous cutaneous sloughs and sores, as well
as by cystitis and nephritis.
_Diagnosis._ This may be based on the progressive onset, unlike the
sudden attack of congestion; on the occurrence of primary fever with
hyperæsthesia or even muscular rigidity, merging into a later paresis or
paralysis; on the retention of urine, followed by incontinence; on the
torpor of the rectum; on the extreme tenderness of the spine in the
region of the inflammatory lesion; and on the tendency to rapid atrophy
of the affected muscles, and the death and sloughing of the skin under
pressure over the prominent parts of the body. The definite localization
of the muscular symptoms, and the different temperature and secretion of
the affected part of the skin, from the unaffected, are further
confirmatory of myelitis.
_Prognosis._ While always grave, myelitis induced by narcotic elements
in the food which can quickly be eliminated from the system, and that
which has not caused compulsory decubitus, or persistent retention of
urine and fæces, may be considered as hopeful. When, on the other hand,
the nature and extent of the lesions have entailed a prolonged
paralysis, or in the large animals, (especially solipeds), a
persistently recumbent position, there is little to be hoped for. The
degenerated myel, and the badly wasted muscles, combine to prevent
rising and the use of the limbs, the sloughing bed sores quickly poison
the blood and general system, and the animal sinks beyond hope of
remedy. Again, if the fæces accumulate in the rectum causing general
retention of the bowel contents and fermentation, the shock to the
nervous system and the toxins absorbed add materially to the prostration
and danger. Finally the retained urine infected through the blood or by
a catheter, quickly passes into ammoniacal fermentation, with softening
and detachment of the cystic epithelium, septic infection of the mucosa,
and the extension of this infection through the ureters of the kidneys.
The complication of infective inflammation of bladder and kidneys
introduces one of the most dangerous conditions possible.
_Treatment._ In an acute case, at the outset, elimination of any
extraneous poison should be sought as the first step toward a
restoration of the normal spinal functions. Purgatives may be employed
to this end, and if the case is urgent and without spasms immediate
action may be sought by a hypodermic injection of 1½ gr. eserine and 2
grs. of pilocarpin. Meanwhile the horse may receive a dose of aloes or
the cow one of Epsom salts. Abundance of watery or demulcent liquids
given by the mouth, or as enemas, should not be omitted.
When plethora has been a prominent factor and symptoms are urgent, a
free bleeding (4 to 5 quarts for horse or cow) from the jugular vein may
serve to relieve the vascular tension, dilute the vital fluid, and
moderate the inflammation. Hot fomentations or sinapisms to the limbs,
and even cupping on the neck and chest, may contribute to relieve the
tension on the spine. When the temperature is already high, bags of ice
may be applied to the tender parts of the spine or those indicated to be
the inflamed parts by the groups of rigid or paretic muscles. Wet
compresses or evaporating lotions may be substituted. In the absence of
mustard, tartar emetic, biniodide of mercury, or euphorbium may be used,
or even croton oil in a carefully guarded manner, but cantharides, oil
of turpentine, and other agents calculated to irritate the kidneys are
to be avoided.
Bromides, hydrobromic acid, potassium iodide, chloral, or belladonna may
be availed of. Some prefer ergot, but this, like strychnia, is of
doubtful effect or positively injurious in most cases in the early
stages. Even in the early stages electricity may be used in the form of
a constant current, which tends to vaso-motor contraction and a better
tone of the capillaries. The electrodes may be applied along the
affected side of the spine so that the current may traverse the affected
part. It may be kept up for ten to twenty minutes at a time and repeated
daily. Any undue suffering under the current may be accepted as a demand
for the reduction of its force or its suspension for the time being.
When the hyperthermia has subsided and the occurrence of paresis or
paralysis demands nervous stimuli, these may be sought in
counter-irritants, strychnia, and interrupted currents of electricity.
The blisters already mentioned may be used. Strychnia may be used
internally (horse or ox 2 grs., sheep ¼ gr., dog ¹⁄₅₀ to ¹⁄₁₆ gr.) or
hypodermically (horse 1½ gr., sheep ⅛ gr., dog ¹⁄₁₀₀ to ¹⁄₃₀ gr.).
Should this excite the animal or aggravate the symptoms it must be
stopped and deferred until the inflammation shall have more completely
subsided. The same remark applies to electricity which may be tried in
the interrupted current, and graduated to the endurance of the patient
or entirely abandoned for the time.
If the patient is able to support itself on its limbs, it is best kept
in a sling to avoid the formation of sloughs and sores. If it cannot so
support itself a very thick soft bed of litter is essential to avoid the
sloughing and septic poisoning. Food must be laxative and easily
digestible such as mashes, hay tea, and boiled or pulped roots. Fresh
green grass may be employed when obtainable.
During convalescence a course of bitters with calcium phosphate and
carefully regulated exercise are important. In tardy cases Trasbot
especially recommends cauterization.