Symptoms. Premonitory indications of apoplexy are less commonly recognized in the lower animals than in man, doubtless largely because of the impossibility of appreciating subjective symptoms. The first observed indications are usually dullness, some lack of coördination of movement, swaying, unsteady gait, trembling and a tendency to deviate to one side or to move in a circle. In the majority of cases, however, the first symptoms noticed are a complete loss of consciousness or nearly so, a sudden fall and often more or less convulsive movements of the limbs aggravated by any excitement. The eyes remain dilated, the pupils enlarged or sometimes contracted, and in case of unilateral effusion the axis of vision of both eyes is turned to the affected side, right or left. The pupil of one eye is likely to be more widely dilated than that of the other. Rolling of the eyeballs is not uncommon. Convulsions may occur, the head and hind limbs being drawn back forcibly as in oposthotonos, or the animal may lie flaccid and comatose from the first. The nasal, buccal and orbital mucous membranes are usually congested, deep red or livid, yet sometimes they are anæmic and pale (Shock). The breathing is usually characteristic, being deep, slow, labored, irregular and stertorous and accompanied by puffing out of the cheeks at each expiration (except in solipeds). Yet there are cases in which stertor is absent. The pulse is usually slow, full and soft, and, in the carotids, throbbing, but it may be weak and imperceptible. There may be complete unconsciousness, and again from the first, or nearly so, there may be a slight response to a stimulus, which cannot be referred altogether to reflex action. In vomiting animals, emesis may ensue. Stupor and coma are more or less marked, though liable to intermissions under any cause of irritation.
Along with the above symptoms the spasms and sequent paralysis, are significant. If confined to given muscles or groups of muscles (monoplegia) it usually implies pressure on some special cortical convolutions presiding over these muscles, and convulsions are to be expected. If there is hemiplegia it is suggestive of implication of the medulla or pons on the opposite side, or of a clot on the corpus striatum or extensively on one side of the cerebrum. A clot in the lateral ventricle tends to profound coma. So liable, however, is pressure to be extended from one side of the brain to the other, and irritation on the one side to rouse a corresponding condition on the opposite side, or in related ganglia, that deductions of this kind cannot always be implicitly relied on.
Though an animal should recover from an attack there is liable to remain some modification of the nervous functions, partial anæsthesia, circumscribed paresis, dullness, lack of energy, irritability, or muscular atrophy.
Cerebral embolism and thrombosis and their sequelæ, infarction and softening, give rise to corresponding symptoms, according to the seat of the lesion, and like lesions of the blood vessels predispose to subsequent attacks.
Diagnosis is based largely on the appearance, usually sudden but sometimes slow, of a more or less profound unconsciousness, attended or followed by paralytic troubles. The history of the case may assist, any blow on the head, or sustained by falling, striking a wall or post, or wearing a yoke, is to be noted. Any extraordinary exertion or excitement must be considered. Any sign of injury about the head; the congestion of the cephalic mucous membranes in contrast with the pallor of shock; the onset of the attack without convulsions (or with them as in epilepsy); the deep coma indicating cerebral hæmorrhage or narcotic poisoning; the absence of the odor of alcohol, opium, or other narcotic from the breath; the turning of the eyes to one side and the inequality of the pupils on the two sides; the turning of the head to the same side as the eyes; the slow, labored, usually stertorous breathing; the slow, full, soft pulse; the occasionally rigid condition of the muscles and finally the paralysis, hemiplegic, and less frequently monoplegic or paraplegic, make up the diagnostic picture.
Uræmia and diabetic coma may be excluded by examination of the urine, pulmonary apoplexy or œdema by the predominance of respiratory troubles, and fulminant anthrax by the examination of the blood and by the fact that this disease does not prevail in the locality.
Treatment is very unsatisfactory in the lower animals, as the disease is very fatal, and unless recoveries are complete, they are not pecuniarily desirable. It is only in the slighter cases, therefore, that treatment can be recommended. At the very outset nothing is better than a full bleeding in a large stream from the jugular vein or temporal artery. Ice, snow, or cold water should meanwhile be applied to the cranial region. Absolute rest should be given, any harness that would impede circulation or respiration removed, and hot water or stimulating embrocations applied to the limbs.
When consciousness returns and the patient can swallow, an active purgative may be administered, or barium chloride or eserine may be given subcutem. Any recurring heat of the head may be met by renewal of cold applications, and the force of the circulation may be kept in check by small doses of bromides or aconite. In case of the formation of a clot, iodide of potassium and other alkaline agents may be resorted to. Quiet and the avoidance of all excitement together with a laxative non-stimulating diet must be secured throughout. A course of vegetable or mineral tonics and an occasional blister to the side of the neck may prove a useful sequel.
CEREBRAL HYPERÆMIA.
MENINGO—ENCEPHALIC CONGESTION.
Passive and active hyperæmia. Causes: passive: obstacles to return of blood: anæmia: active: brain excitement, sun-stroke, violent exertion, fear, abdominal tympany, ptomaines, narcotics, lead, darnel, millet, leguminous seeds partly ripened, tumors, parasites. Symptoms: horse: variable, vertigo, stupor, convulsions, apoplexy, irritability, disorderly movements, strong, hard pulse, congested mucosæ, heat of head, dulness, drowsiness, lethargy, coma, alternating periods of violence, aggravated by what tends to increase vascularity of brain, congested optic disc: cattle: parallel, with special heat of horns: dogs: similar, with desire to move, or wander, or has nausea, howls, snaps. Treatment: cold to head, derivation to limbs and bowels, chloral, bromides, ergot, bleeding, darkness, coolness, non-stimulating food.