Part 21

Even after recovery from the acute or violent symptoms there is liable to remain some aberration or perversion of function, due to the persistence of some encephalic or meningeal lesion. The general hebetude known as immobility may bespeak dropsy of the ventricles, pressure of a tumor or clot, or degeneration of ganglionic centres. Diseases of the eyes (amaurosis, glaucoma, cataract), or of the ear (deafness, disease of the internal or middle ear) are less frequent results.

The supervention of general or facial paralysis or of hemiplegia during the active progress of the malady, is an extremely unfavorable symptom.

Duration. A fatal result may take place at any time by self inflicted injuries (dashing the head against a wall, or falling backward and striking the head on a solid body). Apart from this, death may come within twenty-four or thirty-six hours. If the animal survives two to seven days recovery is more probable. Hering records a case of recovery after five weeks illness. Hot weather hastens a fatal result, while cool, cloudy weather is favorable.

Prognosis. Under rational treatment about one-fourth recover. One-half of the victims make a partial recovery but remain in a condition of dementia or hebetude, blindness, deafness, local or general paralysis which renders them more or less useless. Not more than one-fifth or at most one-fourth of all cases recover. Even in these there is left an increased predisposition to recurrence. It is noted by Trasbot that the mortality is higher in highbred, nervous, irritable animals, which show a tendency to greater frequency, force and duration of the paroxysms of excitement. When decubitus is constant, death may take place from septic poisoning starting from bed sores, and gangrenous sloughing. In other cases there is fatal starvation from inability to eat.

Lesions. In =pachymeningitis= due to mechanical injury there is usually cutaneous and subcutaneous, blood extravasation, and there may be fracture of the cranial bones. The dura mater is dark red, hyperæmic, thickened, covered with exudation and small blood clots mixed with pus cells, and has contracted strong adhesions to the cranial bone. Bony spicula may project into the fibrous neoplasm.

=Leptomeningitis= usually coexists from extension of the inflammation into the adjacent arachnoid and pia mater. There is then a reddish serous effusion into the arachnoid and beneath it, and the substance of both membranes is thickened by exudate, and discolored by congestion and minute hæmorrhages. Whenever the pia mater is thus inflamed, the superficial layer of the brain is implicated, œdematous, soft and doughy. The extension is also made into the ventricles and a serous effusion takes place often to two, three or more times the normal amount (82 grammes Schütz). The choroid plexus forms a yellowish gelatinoid mass, and the ganglia (corpora striata, optic thalamus, etc.), are flattened.

In =encephalitis= the affected superficial gray matter of the ganglia or convolutions, is deepened in color, usually in limited areas corresponding to the disease of the meninges. Sometimes the color becomes of a distinctly reddish tinge, and when cut into shows unusually prominent red points where the capillaries have been cut. Somewhat larger areas of blood staining indicate hæmorrhagic extravasations. The nervous substance is more or less infiltrated with liquid and softened. The nerve cells are swollen, and in process of granular degeneration and the same is true of the myelin, while the axis cylinder is uneven in its outline. Apart from the numerous minute petechial hæmorrhages there is an abundant migration of leucocytes which are found scattered in the degenerating and softened nervous tissues.

The softening of the nervous tissue may result in a pulpy material, which in the comparative absence of blood is grayish (=gray softening=), if abundantly infiltrated with blood is red (=red softening=), if older and discolored is yellow, as in an old extravasation, (=yellow softening=), if thick and viscous is =gelatinoid softening=. If the exudate becomes organized into fibrous material it is a =connective tissue sclerosis= or a =cicatrix=. If the softening exudate becomes purulent it constitutes a =cerebral abscess=. Cerebral abscess is especially common as secondary abscess in strangles or contagious rhino-adenitis in the horse, but may occur as the result of the presence of any pyogenic germ.

Diagnosis. While there is a certain similarity to =rabies=, the horse with encephalo-meningitis is distinguished by the absence of the extreme hyperæsthesia and irritability, of the persistent neighing and squealing, of the rapid alterations of the voice, hoarse and shrill, of the hallucinations, as following imaginary objects with the eyes, of the readiness to attack with teeth or heels when in any way disturbed or excited, of the disposition to get violently excited when a dog is brought near, or in the case of a stallion to show generative excitement.

From =cerebral congestion= it is to be distinguished by the greater severity of the paroxysms, or the deeper character of the stupor, but above all by the presence of the hyperthermia and other indications of fever.

=Immobility= which presents the symptoms of drowsiness, stupor and hebetude, is also unattended by fever, or anorexia, shows a healthy condition of the functions, of respiration, digestion and assimilation and a restful condition when left quiet and still.

The cerebral excitement that sometimes appears in =influenza= is really an encephalitis complication, but its specific cause is recognized in the local prevalence of the infectious disorder, and the inflammatory or catarrhal condition of the mucous membranes.

The diagnostic manifestations of meningitis and encephalitis respectively are given under symptoms.

Symptoms in Cattle. In cattle encephalo-meningitis supervenes on congestion, and sometimes comes on abruptly in connection with traumatic injuries, acute gastric disorder, leadpoisoning, or narcotism. The cases of cerebral parasitism are usually slow in their onset.

Upon the preliminary dullness and somnolence there supervenes excitement, manifested by loud bellowing, pushing the horns, forehead or teeth against the wall, labored often stertorous breathing, a fixed eye often with dilated pupil giving it a peculiar glaring appearance, movements of the jaws, frothing at the lips, tremors, muscular spasms, twitching, or a restless disposition to move, in a circle, in a straight line or less frequently backward. The patient seems to see nothing and is utterly regardless of obstacles. Sometimes the animal plunges violently into manger or rack, against or through the partition of his box, through fences, into ponds, pits, quarries and other dangerous places that may be accidentally in his way. The paroxysms may be intermitted by intervals of comparative calm, and tend to merge into a condition of dulled sensation, staggering, stupor, hebetude and paralysis. The congested conjunctiva and, when it can be seen, the optic disc will correspond to the cerebral congestion. These cases usually proceed to a fatal issue in a few hours. Some cases, however, make a good recovery after a few days of dullness and prostration. In cases that are connected with lead poisoning, or the toxic action of narcotics in the fodder, the attendant circumstances will assist in the diagnosis. From malignant catarrh implicating the encephalon, it may be distinguished by the absence of the catarrhal inflammation of the conjunctiva, pituita, sinuses, buccal mucous membrane, and genito-urinary passages. Also of the tendency to implication of the hair follicles and the keratogenous tissue of the frontal horns.

In the Edinburgh Veterinary Review, Dundas describes a form of alcoholism in cows caused by feeding these animals on “burnt ales” in the vicinity of distilleries. The ale is given by steeping straw in it, and the animals will also drink it freely. They often sleep soundly after such a beverage or give evidence of intoxication. The head is turned singularly to one side and slightly elevated. The pupils are widely dilated, and the eyes have a remarkably wild appearance. On being approached the animals wink rapidly and tremble. There is marked heat of head, horns, and ears. When pressed with the finger in the axilla they fall instantly and when pulled by the head they incline to turn over. The pulse is 70 to 80 per minute. Delirium and loss of coördination of the muscular movements set in, and in case of survival various forms of chronic brain disease are manifested. In one cow the violent symptoms came on with the near approach of parturition. The post mortem lesions consisted in ramified redness and punctiform blood extravasations in the pia mater and meninges. The brain substance was softened and clots of blood were found in the lateral ventricles. Congestion and extravasations were also found around the cervical myelon. (See Alcoholic Intoxication).

Symptoms in Sheep. The sheep is often drowsy, dull and stupid, lying by itself with head low or laid backward. During the periods of excitement it works the jaws, froths at the mouth, carries the head turned in one direction, upward or lateral, bleats piteously, pushes against the wall, has uncertain, stiff or staggering gait, or convulsions, and finally paralysis. The head is hot, and the eye fixed, congested or sometimes rolled upward or squinted. Symptoms in the goat are nearly the same. The cœnurus disease is more gradual in its onset, and produces periodic paroxysms corresponding to the activity of the heads of the parasite when protruded into the brain substance. It is mainly confined to sheep of one year and under and that are kept where dogs have access.

Symptoms in Swine. Pigs may at first have a period of dullness or restlessness, the latter merging into active delirium. The patient champs his jaws, froths at the mouth and nose, sometimes vomits, squeals, raises himself with fore feet on the wall, walks round and round, or falls and rolls over, has tremors or convulsions.

Symptoms in the Dog. There may be preliminary indications of illness, anxiety, restlessness, irritability and a desire for seclusion. Vomiting may occur. This is liable to merge into prostration, a dullness of the special senses, utter inattention to calls, yet a disposition to resent any interference, a readiness to bite, at least to howl, when handled. Some will constantly howl or moan. The eye is fixed, the pupils dilated, the conjunctiva deep red, the head and roots of the ear are hot. The expression of the face is pinched and drawn, the muscles may twitch, the eyes roll, twitching of the neck or limbs may appear, and even epileptiform attacks. In exceptional cases the symptoms approximate to those of rabies, in the tendency to seek seclusion, to wander off, to bite on any interference, and even to gnaw the bars of the cage or any object within reach. After more or less of such excitement, the period of stupor, coma, paresis, or paralysis comes on, and the animal dies in a state of complete nervous prostration. In cases associated with the linguatula tænioides the sneezing, nasal discharge and nasal congestion, even in the early stages, betray the true character of the disorder.

The rabiform cases usually lack the intense heat of the head, the deep conjunctival congestion, the depraved appetite, the alteration of the voice, and the mischievous desire to attack without reason which characterize rabies.

Treatment. In all cases of phrenitis, quiet, darkness, and coolness are especially demanded. For the horse a roomy, loose box or a well fenced yard may be secured, and if he can be secured by a halter from a point above the level of the head and in the centre of the box it will obviate the increase of congestion by hanging of the head. The application of cold to the cranium in the form of wet cloths, ice bags or irrigation is always in order, and should be continued so long as heat of the head and other indications of cranial hyperæmia last.

In the horse suffering, as is so often the case, from narcotic poisoning an active purgative is one of the first considerations to clear away any remains of the poison from the prima viæ. An ounce of aloes may be safely given, as there is in this case little danger of superpurgation, and, to secure an even more prompt response, eserine (1½ grain) or barium chloride (½ drachm) may be given subcutem. Or an ounce or two of glycerine by the rectum might be used as a substitute for these last. The action of the purgative proves not only eliminant and therefore antidotal, but it is a most effective derivative from the brain. When the restlessness or excitement is very great we may use acetanilid, trional, sulphonal or some one of the many brain sedatives and antithermics. Sedatives, or anodynes like opium, which tend to increase cerebral congestion are dangerous.

Bleeding from the jugular or temporal artery, has been objected to on the ground that it tends to increase the exudate and therefore the pressure and cerebral anæmia. On the other hand it often proves of great value in vigorous, muscular and plethoric horses in temporarily lessening the blood pressure in the brain, and affording the walls of the overcharged capillaries an opportunity to resume a more normal tone and to control that very exudation which is so much dreaded. It is most effective in the early stages when little or no exudation has taken place and may then be pushed to the extent of producing a perceptible softening of the pulse (4, 6 or 8 quarts). Even in the advanced stages when exudation has led to stupor or coma a moderate and carefully guarded bleeding may favor reabsorption of the liquid exudate. In weak and anæmic cases in which general bleeding appears to be contra-indicated the shaving of the cranial surface followed by leeching or wet cupping can be safely resorted to.

Counter-irritants like bleeding are denounced and advocated by different practitioners. In cases of extreme hyperæsthesia where excitement and fever would be dangerously increased by their use, they must be discarded, or used only in the modified form of soothing hot fomentations to the extremities. Where there is less sensitiveness mustard poultices or pulp applied on the sides of the neck, or upon the limbs, or even more energetic blisters will be of great service.

After the action of the purgative the bowels may be kept free by calomel in ½ drachm doses twice daily and as much sulphate of soda as may be necessary.

Iodide of potassium (1–2 drs. twice a day) is beneficial as an antithermic a circulatory sedative, an eliminant, and probably at times as an antidote but it cannot be given while calomel is used. Certain it is that it often seems to act well in succession to the purgative, in cases of poisoning by ryegrass and leguminosæ.

When fever runs very high it may sometimes be admissible to give aconite, but the coal tar products are much more prompt and powerful, and may therefore be more hopefully employed for a short time.

In conditions of extreme prostration, stupor, or coma, stimulants are resorted to, but too often with no good effect, the exudation and compression which many times cause such symptoms being rather aggravated than benefited by such agents.