Part 17

In cases of =gastric vertigo= an active cathartic, followed by smaller laxative doses or a laxative diet and a course of bitters may prove useful. Such cases should never be worked on a full stomach but should be left at rest for at least an hour after a meal.

In =aural vertigo= special attention must be given to the throat, and external ear. Bromides may often be useful, and sometimes benefit may be derived from an occasional blister or light firing back of the ear.

In =cœnurus cerebralis= in sheep the only resort is to trephine and remove the parasite.

CONCUSSION OF THE BRAIN.

Definition. Causes: leaps, trips, falls, blows. Symptoms: fall, insensibility, flaccidity, suspended respiration, tumors, vomiting, recovery, signs of cerebral congestion. Pathology: anæmia followed by congestion. Diagnosis: from fracture, epilepsy. Treatment: quiet, rubbing of limbs, ammonia, cold to head, or heat; for congestion, bromides, depletion, ice pack, derivatives.

Definition. Concussion is the condition produced by mechanical jar or shock of the cerebral mass, and manifested by modification of the brain functions of any grade from a simple dazed condition to that of complete unconsciousness.

Causes. The most familiar cause is the stroke of the butcher’s pole axe, producing sudden and absolute insensibility. A horse in leaping, trips and falls on his head or running against a wall sustains a concussion, which leaves him for some seconds without any signs of life. The same will happen to other animals, but above all to rams which in their combats, back for a number of yards and running together meet with a shock from the effect of which even their thick skulls cannot save them. Other blows upon the head operate to the same end.

Symptoms. Concussion is manifested by different grades of symptoms. At first there is usually a fall with complete insensibility. The animal lies flaccid, utterly insensible to external irritation and there is suspension of respiration. The heart continues to beat and a frequent weak pulse may be often detected. In slight cases, breathing may be reestablished at the end of a minute or two, with muscular tremors and movements of the limbs; then the animal rises, shakes his head, neighs, and walks at first unsteadily and afterward with greater and greater firmness. In vomiting animals, emesis occurs.

In some cases this may be followed, after an hour or two, by signs of congestion, heat of the head, redness of the eyes, irritability, or dullness and stupor and perhaps muscular twitching. This may improve or it may terminate in death preceded by spasms, general convulsions, rolling of the eye balls, and stupor or coma with general muscular relaxation.

The primary condition is usually an anæmia of the cerebral matter as seen in the brain of the animal suddenly killed by the blow of a hammer. The return of consciousness or semi-consciousness is connected with the resumed freedom of the cerebral circulation. The later convulsions, stupor or coma, usually imply active congestion or the effusion of blood on the brain surface, or in its substance.

Diagnosis from fracture must be made mainly by manipulation of the bone in the seat of the blow, and by the absence of the increasing stupor and coma which attend on pressure from a gradually increasing blood clot. From epilepsy it is to be distinguished by the evidence of mechanical injury, by the absence of spasms at the first, by the suspension of breathing and the absence of froth about the lips.

Treatment. Keep the patient still and prostrate until there are signs of returning respiration and free cerebral circulation. This may be hastened, however, by active rubbing of the limbs and body, by giving guarded inhalations of ammonia, or even by friction of the skin with ammonia and oil. Sometimes reaction is favored by dashing cold water on the head, while in other cases hot water to the poll will prove more effective, or the two may be used alternately with good results.

If, after partial recovery, there is marked restlessness, or irritability it may be met with bromides. If secondary unconsciousness supervenes effusion of serum or blood is to be feared, or extreme congestion, and blood may be drawn from the jugular or by cups from the cranium, and ice bags or cold water may be applied to the head. Hot foot baths or mustard embrocations applied to the limbs, and even derivation toward the bowels may be used. The indications for treatment come to be for meningo-encephalitis.

LIGHTNING STROKE. ELECTRIC SHOCK.

Fatal. Non-fatal. Herbivora at pasture under tree. Symptoms: dazed for a few minutes, unconscious for hours, permanent paresis or paralysis. Lesions: lines of burned hair, skin or muscles, rigor mortis slight, decomposition rapid, bluish black venous and capillary congestion, extravasations, blood fluid. Diagnosis. Treatment: ammonia, ether, alcohol, caffein, nerve stimulants.

While a stroke of lightning is usually fatal, yet in certain cases, the victim is but temporarily stunned and recovers with more or less remaining paralysis. The subject has also great importance in connection with the claim of the owner against a company which may have insured his stock against lightning.

Any animal may be struck, but the herbivora which are turned out to pasture are especially liable to such injuries, because they seek shelter under trees, which operate as lightning rods.

Symptoms. In slight cases of shock whether by lightning or the current of a hanging live electric wire, the subject may be simply dazed and may or may not fall to the ground, and recover itself in a very few minutes. In other cases there is a more violent shock which prostrates the animal to the earth, where it may lie unconscious for some hours and yet quickly and completely recover. In still other cases after such prostration recovery is incomplete and the animal remains affected with paresis or paralysis of one or more, commonly of both hind, or all four limbs. In the more violent shocks death is instantaneous.

Often the impact and course of the current are marked by visible lesions. Sometimes the skin is wounded exposing a bluish black tissue beneath. More commonly there is an area of burnt hair, or straight, radiating or angular lines of raised and frizzled hair marking the course of the current. In a horse killed by an electric light wire in Ithaca recently the current had burned to a depth of several inches in the muscles of the shoulder which rested on the wire.

Lesions are often rather indefinite. There may be no appreciable change in the nervous system. Rigor mortis is slight; it passes off rapidly and decomposition sets in early. The venous system and capillaries are usually filled with liquid blood of a dark bluish black color, and at intervals are points, spots and patches of blood extravasation. The uniformly liquid state of the blood is one of the most marked phenomena of death from electricity. The dark blue congestion of the radical veins is also very pathognomonic, the part struck or traversed by the main current, being the seat of the most elaborate arborescent network. This arborescent appearance of the dark colored veins, and the petechiæ are often marked in the internal organs (brain, kidneys, liver, lungs).

Diagnosis. The environment of the animal will often clear the diagnosis. The patient is found helpless, or dead under a tree, by a pole, or under a hanging wire, and if a tree there are evidences of the electric shock in scattered leaves and branches, stripping off of the bark, or perhaps rending of the tree in pieces. In case of wires attached to or passing near such a tree, the supporting poles show similar splitting and rending. Add to these the fluidity of blood in the carcase, the thickly ramifying network of the minute dark bluish, red veins, the petechiæ and the comparative absence of cadaveric rigidity, and we have a picture very significant of lightning stroke.

Treatment in such cases is according to the condition. The primary unconsciousness is met by inhalations of ammonia or ether, or the injection of brandy or alcohol subcutem. Caffein, atropine or hyoscyamin may be used as substitutes. If consciousness returns recovery is usually rapid and complete. Should paresis or paralysis remain it must be treated like any ordinary case of these affections.

INTRACRANIAL HÆMORRHAGE AND THROMBOSIS. APOPLEXY. SOFTENING OF THE BRAIN.

Definition. Causes: Nature: intracranial rupture, with pressure, serous effusion, excessive congestion, experimental cases, anæmia from pressure, comparative immunity of horse, heart disease, Bright’s disease, atheroma, degeneration, emboli, age, blood tension, severe exertion, excitement, concussion, insolation, venous obstruction, toxins, neoplasms. Lesions: blood clots, small and multiple, large and solitary, brain absorption, cavities, cysts. Symptoms: dullness, swaying, trembling, elevation of head, turning in circle, sudden fall, spasms, unequal dilated or contracted pupils, eyes turned to affected side, congested or anæmic mucosæ, stertor, puffing cheeks except in solipeds, pulse slow, soft, full, vomiting, stupor, coma, unconsciousness, paralysis, monoplegia, hemiplegia, sequelæ. Diagnosis: sudden unconsciousness, with little spasm, but paralysis, history, sign of trauma, deep coma, eyes turned to one side, pupils unequal, stertor, slow breathing and pulse; from uræmia, pulmonary apoplexy, œdema or anthrax. Treatment: bleeding, ice pack, snow, cold water, rest, derivatives to limbs, later purge, bromides, potassium iodide, tonics, open air life.

Definition. Cerebral apoplexy has been defined as a sudden loss of sensation and voluntary motion, from pressure originating within the cranium and followed by paralysis, often unilateral. The definition is somewhat insufficient as regards the early symptoms as the same conditions attend on convulsions and epilepsy (haut mal), and it is only by excluding these by their characteristic features of sudden seizure with clonic spasms and their intermittent and paroxysmal habit that we reach an easy and satisfactory distinction. Later the paralysis tends to identify the apoplectic attack.

Causes and Nature. The immediate cause and essential lesion of apoplexy has been generally held to be the rupture of an intracranial artery and the formation of a considerable blood clot which presses upon (and abolishes the functions of) the brain. There are cases, however, in which the characteristic symptoms are present, and yet a complete recovery ensues at an early date, too early to allow for the absorption of a considerable clot. Moreover, in fatal cases perhaps no blood clot is to be found, but in place a serous effusion, or an internal congestion which exercised the fatal pressure on the brain. So far, therefore, as clinical phenomena are concerned, we must allow that apoplexy may arise from any sudden pressure on the brain substance. Pagenstecher produced the symptoms of the disease by injecting, at a regulated pressure, melted wax and tallow between the skull and dura mater in the dog. In the moderate cases there were drowsiness, psychic depression and general muscular weakness. In the more severe ones there were added sleep and unilateral paralysis. In the more extreme cases death followed in a few hours after coma set in, though in some of these a partial recovery ensued if the waxy mass was scooped out before the fatal symptoms appeared. Cases ended fatally only when the injection pressure equalled that of the blood, and convulsions occurred only when the pressure was unsteady. The temperature fell as it does in apoplexy in man, at the outset, but it continued falling to the fatal issue contrary to what takes place in man.

Duret injected water into the cranium of animals so as to produce great tension of the occipito-atloid membrane causing thereby arrest of the respiration and slowing of the heart’s action. On tearing the membrane so as to allow escape of the water, respiration began anew and consciousness was gradually restored.

Edes sustains the view that apoplexy is directly due to anæmia of a lesser or greater portion of the brain substance, and that this need not be in any one particular seat nor of any definite extent. This anæmia is usually induced by pressure and may be caused by effused blood, or serum, or by the extreme congestion due to narcotic poisons, or other cause. Embolism of a cerebral vessel, however, by cutting off the blood from the part of the brain which it supplies may give rise to the apoplectic phenomena.