Part 33

1st. =Enforced inactivity.= In every instance that has come under my notice the ewes have been confined for several months to a barn or at most a confined yard so that exercise became impossible. The muscular system was flabby and soft, although as a rule there was abundance of fat, and the number of red globules did not vary much from the normal. In an animal that is naturally so active, and so accustomed to outdoor life the reduction of tone and vigor is to be expected. The same evil shows in other directions, thus after a snowy winter and close confinement the crop of lambs will sometimes perish of goitre without exception, while in subsequent years, with enforced exercise of the ewes, practically all escape.

2d. =Twin lambs= have been found in the womb of almost every case examined. The extra drain upon the system, and the depressing action of the load on an atonic ewe together with the symptomatic irritation are to be noted.

3d. The near approach of the =completion of gestation=, the cumulative effect of a long pregnancy, and perhaps the absorption of metabolic products from the fœtal membranes in course of preparation for detachment, and of leucomaines from the physiologically active or developing mammæ, doubtless have a prostrating influence on the susceptible nervous system.

4th. All had been fed on =clover hay= either as an exclusive diet or as part of their ration. This is sufficiently nutritive, as testified by the fat condition of the patients, but it may be that it was too nitrogenous for such an inactive life. Again the clover hay usually abounds in cryptogams and bacteria and their products, which may have contributed somewhat to the asthenia.

5th. =Concurrent diseases=, in individual cases or flocks, manifestly contributed to the general loss of nervous power. In some the bowels were studded with the nodules of the œsophagostoma, in others œstrus larvæ had extensively invaded the nasal sinuses, one had congestion of the mucosa of the small intestines, some had congestion and fatty degeneration of the liver, others had fatty kidneys, and one had a papilloma pressing on the spinal cord. Manifestly diseases and degenerations of various kinds would still further undermine nervous energy and add to the atony.

Cold and heat did not seem to dominate, as most were kept in warm barns, and wore heavy winter fleeces, while one clipped early in December, and kept in an atmosphere of 40° to 55°, was attacked in the second week of January.

As this experience was had in a goitre district it may become a question whether the poison of this disease was a causative factor. Goitre was not a prominent feature in either ewes or lambs.

Symptoms. Variable. The most prominent are, leaving the flock, moping alone, grinding the teeth, drooping and trembling of head and ears, temperature normal or subnormal (100.5°), respiration 24, pulse 80, feeds and ruminates sparingly, bowels normal, buccal mucosa pale, conjunctiva hyperæmic, in some cases stupor and partial blindness, the animal walking against racks or fences, walk is slow and unsteady, the muscles feel soft and flabby, the abdomen may be full, but its walls are quite flaccid so that the lambs can be easily felt. As the disease advances all symptoms are aggravated, food is no longer taken, rumination ceases, the ewe remains recumbent, cannot be made to rise, and when lifted and carried makes no struggle. After 24 hours of this helpless condition death supervenes. In some instances labor pains have come on and the ewe has perished in a vain effort at delivery. Illness lasted about a week.

Prominent lesions have been noted under causes. It need only be added that no notable difference from the normal was found in making a count of the red globules, and the size of the individual globule was normal or only perceptibly smaller as is to be expected in a dense plasma. In different cases there was found congestion of the abomasum, small intestine, liver and brain.

Prevention. The most important measure is to maintain a strong, well-developed muscular system, and a vigorous nervous tone by a sufficiency of out door exercise during the winter months. Half a mile or a mile at least should be given daily to the breeding ewes, no matter what the attendant difficulties. If clover hay is musty it should be replaced in whole or in part by another kind. Parasites and other diseases which tend to lower the general tone should be appropriately treated.

Treatment. When once established, the disease has not been successfully treated. Nerve tonics are indicated.

NEURITIS. PERINEURITIS.

Definition. Causes: traumas, poke, stanchions, collar, yoke, interfering, neurectomy, fractures, tumors, callus, rheumatism, gout, violent overdistension. Lesions: nerve sheath red, swollen, exudate, leucocytes in excess, fibroid thickening, nerve atrophy, degeneration, axis granular, myelin in oily globules, peripheral extension. Muscular degeneration and atrophy. Symptoms: tenderness, swelling, muscular atony, wasting, spasms, twitching, decreased excitability, paralysis, in section swelling on proximal end. Prognosis: disability for weeks, months or year; response to electric current, operability of tumors, curability of rheumatism or gout, hopeful conditions; long standing degeneration, etc., unpromising. Treatment: rest, soothe, anodynes, splint with soft pad, essential oils, lead and opium lotion, ice, snow; derivatives; laxatives; diuretics, anti-rheumatics, Faradisation.

Definition. Inflammation of a nerve leading to paralysis of the parts to which it is distributed.

Causes. Traumatism is the most common factor. Among the common examples are injury of the seventh nerve above the angle of the lower jaw, by a poke worn in pasture by the horse, or by stanchions in the cow. Hogs may suffer from blows of the triangular neck gear worn to prevent them from breaking through fences. Blows by the yoke, incised and contused wounds implicating the nerve, such as neurectomy, and the blows received in interfering, and compression by tumors or bony growths, are familiar examples. Fractures with displacement, notably those of the sacrum and proximal end of the coccyx with caudal paralysis, are not uncommon. In fractures of the limbs the pressure upon or wounding of a nerve. Again, the callus on the seat of fracture may induce neuritis by pressure, as may also the projection of the end of a bone in luxation. Rheumatism affecting the nerve sheaths and, in birds and swine, gout, are additional factors. Violent overdistension, and even chronic muscular spasm, are quoted as causes.

Lesions. The early changes are mainly in the connective tissue sheath, which becomes hyperæmic, red and swollen, with a gelatinoid exudate and a great multiplication of leucocytes. Later, the interfibrillar connective tissue is involved and the nervous substance proper undergoes hyperæmia and degeneration. The axis cylinder undergoes granular degeneration and the myelin breaks up into oil-like globules. The lesions are at first limited in extent, though there may be more than one focus, and the resulting degeneration of the nervous filaments advances toward the periphery in accordance with Waller’s law by which disease changes proceed rapidly in parts cut off from their trophic cells.

The muscles supplied by the inflamed nerves also rapidly degenerate. The fibres shrink in size, and lose their striated appearance, becoming distinctly granular, and pale. Round cells are formed in excess in the sarcolemma and muscular fibre, and if the morbid condition persists there is fibroid degeneration, cirrhosis and contraction.

Symptoms. In the absence of the subjective element of pain, which is the most constant symptom in man, we must rely mainly on the exquisite tenderness on pressure along the line of the nerve, but localized at some particular point, on the swelling at such tender point and on the loss of muscular power or even of sensation in the tissues corresponding to its peripheral distribution. The muscles may be hypersensitive and are usually flaccid if not from actual paralysis, still from the pain which attends on their contraction. In some cases they are the seat of clonic spasms or twitching. Under a current of electricity they show a decreased irritability which bears a direct relation to the grade of degeneration which has occurred in the nerve fibres. In cases of deep-seated neuritis paralysis may be the only appreciable symptom. In traumatic injuries like bruises of the seventh nerve or fracture of the sacrum the local swelling and tenderness are marked initial symptoms, upon which supervene the paralysis and atrophy of the muscles cut off from full innervation. In neurectomy the tender swelling in the stump which is still in connection with the nerve centre may amount to a distinct neuroma, while the peripheral and detached portion of the nerve steadily loses its irritability as shown by electric stimulus.

Prognosis. This will depend on the nature of the lesion. A single transverse section of a nerve, without loss of substance may be repaired in a few months, while with loss or degeneration of a considerable part of its substance it may maintain a paralysis for years or even permanently. Lesions due to slight bruises may recover in a few weeks, while the more severe ones will persist for months or years. The response to electric stimulus distal of the lesion, is a guarantee of the absence of degeneration and a feature hopeful of recovery. Pressure by bony displacement or neoplasia must be done away with as the first condition of improvement in such cases. Rheumatic and gouty cases will persist until these constitutional infirmities are corrected.

If the neuritis and paralysis have lasted for any length of time, the degeneration of the muscles will keep up a degree of muscular weakness (and if in the limbs lameness) after the repair of the nerve has been completed.

Treatment. Rest is the first consideration accompanied by soothing and anodyne application to the inflamed nerve. When neuritis exists in a limb a softly padded splint may be useful at first. The skin over the inflamed nerve may be rubbed by one or a combination of the anodyne essential oils, (oil of cajeput, oil of peppermint, oil of lavender). If the pain and tenderness are extreme, a bag of ice or snow may give relief and should be kept applied for a length of time. Or hot fomentations with a lotion of lead and opium may be preferred especially in rheumatic cases. If blisters seem to be called for, aqua ammonia and oil of turpentine may be added to the essential oils, or muriatic acid may be applied with a glass rod in points along the line of nerve. A laxative of Epsom or Glauber salts will often prove of great value at the outset and may be followed by diuretic doses of potassium iodide, potassium nitrate or acetate, and in rheumatic cases sodium salicylate. In these last forms, as also in gout, the carbonates and acetates of the alkalies, colchicum, and salicylates are especially to be persisted with. In these, too, rubefacients and blisters are often of essential value and may be repeated again and again.

Faradism is of little account during the active stage of neuritis excepting as a test of the progress and extent of the degeneration, but when inflammation has subsided nothing contributes more to the restoration of the tone and healthy nutrition of both nerve and muscle. The current is to be sent along the line of the paretic nerve and muscles for ten or fifteen minutes at a time and not less than once a day.

NEURALGIA.

Intermittent or remittent pains, in line of nerve without inflammation, or other structural lesion. Diagnosis: lameness, stiffness of particular muscles having a common nerve. Unnatural position habitual. Pain of inflammation and of neuralgia. No functional change. Rheumatism. Tumors. Causes: lead, rheumatism, gout, auto-poisons, cold, anæmia, reflex. Facial neuralgia, occipito-cervical, dorso-intercostal, lumbo-abdominal, sciatic. Treatment: elimination, of lead, etc.; intestinal antiseptics, tonics, hot water, anodynes, arsenic.

This is characterized by pain paroxysmal, intermittent or remittent situated in the course of given nerves. It must be a pure neurosis and unaccompanied by any specific structural lesion like inflammation, degeneration, atrophy, hypertrophy, tumor or the like. It is therefore manifested subjectively and cannot be easily identified in the lower animals. Nevertheless, Lafosse, Zundel, Genée, and others have recorded cases, their conclusion being deduced from symptoms which were held to indicate nervous suffering in the absence of any structural lesion whatever. A priori one can with difficulty escape the conviction that neuralgia must exist in the lower animals as in man, and the only drawback to its recognition is the difficulty of diagnosis.

The first step in such diagnosis must usually be the presence of lameness, stiffness or indisposition to free movement of some particular muscle or group of muscles deriving their innervation from a particular nerve. Or there may be a particular position habitually assumed such as semi-closed eyelids, drawn back ears, laterally inclined neck which strongly suggests nervous suffering. Next, there must be the exclusion of any appreciable structural cause and especially of inflammation. The three prominent features of the pain of inflammation is that it is aggravated by pressure, it is heightened by movement, and it is accompanied by some decided alteration of the function of the part. If there are at the same time exudation and swelling, inflammation is all the more certainly indicated. In a neuralgic pain on the contrary pressure does not increase the pain: it may even alleviate it: movement of the part may be rather satisfactory to the patient than painful; and the disturbance of function, contractile, secretory, trophic, is not perceptible. There is no local exudation nor swelling to account for the nervous disorder.

The liability to confound the affection with a neuritis more centrally situated, but the pain of which is referred to the periphery of the nerve, is to be obviated by a tracing of the nerve along its course to the nerve centre so as to identify any centre of tenderness, and also by the implication of all the peripheral branches coming off ectal of that point.

Again, rheumatism may be easily confounded with neuralgia, but here the affected nerve and muscle and even the skin over it is liable to be very tender to the touch or pinch, and if at all acute some hyperthermia is present. Like rheumatism, neuralgia shows a tendency to shift from place to place.