Part 12

Epilepsy is the name given to a class of cases characterized by a sudden and transient loss of consciousness with a convulsive seizure, partial or general. It appears to be due to a sudden explosive discharge of convulsive nervous energy, which may be generated by a great number of causes of morbid irritation—pathological, traumatic, or toxic. As a rule the epileptic seizure is but the symptomatic expression of a complex derangement which may be extremely varied as to its nature and origin.

Frequency in different animals. The affection is far less frequent in the domestic animals than in man, doubtless because of the absence of the special susceptibility which attends on the more highly specialized brain, the disturbing conditions of civilization, and the attendant vices.

Among domestic animals, dogs are the most frequent victims in keeping with their relatively large cerebral development, their emotional and impressionable nature and the unnatural and artificial conditions in which as house pets they are often kept. Their animal food and the consequent uric acid diathesis is a probable cause, as it is in man. In ten years of the dog clinic at Alfort they made an average of 3 per cent. of all cases. Next to the dog the pig kept in confinement is the most frequent victim, while cattle and horses come last. At the Alfort clinic epileptic horses were not more than 1 per 1000 patients. It is not at all infrequent in birds, especially canaries and parrots. Reynal has seen it in sparrows.

Divisions. The disease has long been divided into petit mal and grand mal (haut mal). The =petit mal= (slight attack) is usually a transient seizure affecting a group of muscles only and associated with only a momentary or very transient loss of consciousness. The loss of consciousness is uncertain as to many cases. Under partial epilepsies must be included the hemi-epilepsy, or Jacksonian epilepsy, which is confined to one side of the body.

The =grand mal= (severe attack) is one in which the loss of consciousness is complete, and the convulsions are general in the muscles of animal life.

Another division is into =symptomatic= and =idiopathic= cases, and if this distinction could always be made it would be of immense value in the matters of prognosis and treatment as the removal of the morbid state of which epilepsy is the symptom will usually restore the patient to health. Thus the removal of worms from the alimentary canal, of indigestible matters from the stomach, of a depressed bone or tumor from the surface of the brain may in different cases be the essential condition of a successful treatment.

Morbid Anatomy and Pathology. The literature of epilepsy is very rich and extensive and yet no constant lesions of the nervous system can be fixed on as the local cause of the disease. A review of the whole literature leads rather to the conclusion that irritations coming from lesions of the most varied kind, acting on a specially susceptible brain will rouse the cerebral centres to an epileptic explosion. Thus epilepsy has been found to be associated with lesions of the following kinds:

1st. Brain lesions of almost every kind, including malformations.

2nd. Lesions of the walls of the cranium.

3d. Disorders of the cerebral circulation.

4th. Lesions of the spinal cord.

5th. Morbid states of the circulating blood (excess of urea, uric acid, creatinin, lead poisoning).

6th. Reflected irritation, as from dentition, worms, sexual excesses, injuries to certain nerves, notably the sciatic, or to particular parts of the skin.

1st. =Brain lesions.= Those which affect the medulla and the cortical convolutions around the fissure of Rolando would be expected to be implicated because these centres preside over the principal motor actions of the body and limbs. Yet though these parts are found to be affected with various morbid lesions in a certain number of cases of epilepsy, such lesions are exceptional, rather than the rule. In 20 cases of epilepsy in man, 15 showed no lesion whatever of the brain. Blocq and Marinesco, pupils of Charcot, recently made a critical examination of the medulla and Rolandic cortex in nine cases that died during the fit. All showed granular bodies (degenerated myelin or blood pigment) in the perivascular sheaths but they found these in disseminated sclerosis and even in healthy brains as well. The neuroglia cells of the first cortical layer contained black granules. Otherwise four cases had no change, while five showed sclerosis of the cortex. The medulla was sound in all cases excepting one which showed punctiform hæmorrhages. Visible lesions may be present in other parts of the brain; Wenzel long ago claimed constant lesion of the pituitary body. Beside the cerebral cortex, lesions have been found in the bulb, the hypoglossal nucleus, the olivary body, the hippocampi, the thalamus, the corpus striatum, the quadrigemini, the cerebellum, etc. Hughlings-Jackson who made an extended investigation of the subject concludes that any part of the gray matter of the encephalon may become over-excitable and give rise to a convulsive attack. Not only may the lesion be in any part of the brain, but it may be of any kind: meningitis, cerebritis, softening, tubercle, tumor, hydatid, embolism, or dropsy. Marie Bra found an extreme asymmetry of the cerebral lobes in epileptics. Kussmaul and others found stenosis of the vertebral canal and asymmetry of the two lateral halves of the medulla.

2nd. =Cranial lesions.= These consist largely in blows or falls upon the head, with osteitis, periostitis, fractures with depressions, fibrous neoplasia implicating or not the meninges and pressing on the brain, hæmorrhages from minute arteries, etc. The diagnosis of such lesions will often open a way to a successful treatment. Baker found most of the severe cases from head injuries.

3d. =Disorders of the cerebral circulation.= Burrows, Kussmaul and Turner showed that in animals, loss of consciousness and epileptiform convulsions followed on cerebral anæmia caused by profuse bleeding or by compression of the carotids. The same has been observed in surgical cases after ligation of one common carotid. Hermann caused convulsions in a rabbit by ligating both anterior and posterior venæ cavæ.

4th. =Lesions of the Spinal Cord.= Brown-Sequard determined epileptiform convulsions by transverse section of one-half of the spinal cord, or of its superior, lateral or inferior columns. The later development of the doctrine of interrupted spinal inhibition, suggests that, many of the seizures in question are but exaggerated spinal reflexes, which are no longer restrained by cerebral inhibition. That all are not of this spurious kind may be fairly inferred from his further demonstration that bruising of the great sciatic in animals tended to produce epilepsy. In such cases., the irritation of certain areas by pinching the skin, served to produce a seizure. Not only so, but the animals in which such artificial epilepsy had been induced tended to transmit the infirmity to their progeny. The prevailing view of epilepsy however, would consider such lesions as sources of peripheral irritation by which the brain is affected sympathetically, while the real explosion is the result of the sudden discharge of the pent up excitement caused in the encephalic centres by the irritation at such distant points.

5th. =Morbid States of the Circulating Blood.= Certain poisons, when brought in contact with encephalic nerve centres produce epileptic seizures. Gallerani and Lussana applied creatinin directly to the cerebral cortex and quickly induced epileptiform convulsions and choreiform movements. Injected subcutaneously it failed to produce the same effect. Cinchonoidin acted on the basal ganglia of the brain producing convulsions but no choreiform movement. Poisoning with lead, ergot, nitro-pentan, nitro-benzol and a number of other poisons brings about intermittent convulsive seizures. The same may be inferred of ptomaines and toxins, in the convulsions that appear in the advanced stages of infectious diseases (canine distemper, hog cholera, etc.).

6th. =Reflex Irritation.= Perhaps no peripheral irritation more frequently causes epilepsy, than parasites. In young dogs worms in the intestines (tænia cœnurus, tænia tenuicollis, tænia serrata, tænia echinococcus, and ascarides) have been especially incriminated. Also linguatula tænioides in the nasal sinuses. In young pigs the echinorrhynchus gigas, ascarides and trichocephalus. In horses ascarides have been principally blamed.

Wounds implicating nerves, and tumors pressing on nerves, have served as sources of nervous excitement which accumulates in the cerebral ganglia and bursts forth as an epileptic explosion. Bourgelat mentions the case of a horse which fell in a fit the moment he was touched on his tender withers, also a case in which a seizure coincided with an attack of recurrent ophthalmia. Gerlach saw a horse which had an epileptic fit the instant he was touched on his sensitive withers. In kittens and puppies the irritation attendant on dentition is a common cause of attacks. In nervous dogs and pigs indigestion or constipation may serve as the occasion of an explosion. In the experimental cases of Brown-Sequard, not only did the injury to the sciatic nerve develop in the brain a latent tendency to epilepsy, but the subsequent pinching of the skin in certain areas (epileptigenous zones) promptly brought about a seizure.

=Causes.= Most of the causes of epilepsy have been given above under the head of pathology and morbid anatomy. The nervous predisposition may, like any other peculiarity or function, become hereditary. In the human race nothing is more certain than the tendency to some form of nervous disorder (insanity, dementia, alcoholism, morphinism, epilepsy, chorea, etc.) in a special family line. Reynal records the case of an epileptic cat (belonging to an employe of the Alfort veterinary school) the progeny of which for three generations, became affected with epilepsy and mostly died before they were a year old. Also four epileptic dogs (3 males and 1 female) which produced a number of epileptic puppies. LaNotte records the cases of two bulls affected with epilepsy, in the progeny of which numerous cases of epilepsy appeared; the cows being attacked after the first calving, and the oxen soon after they were first put to work. Breeding stallions are particularly liable to attacks, the high feeding, lack of muscular work in the open air, and above all the oft repeated nervous excitement attendant on copulation being directly exciting causes. The heredity of the artificial epilepsy induced by Brown-Sequard in Guinea pigs, serves to strengthen the doctrine of heredity in ordinary forms.

Among emotional causes fear easily heads the list. Bernard states that a horse became epileptic in connection with the terror caused by the giving way of a wooden bridge over which he was passing. Bourgelat and Reynal adduce instances, in cavalry horses when first put under fire. Reynal records the case of another which had his first attack when facing a moving locomotive, and which never again could see an engine in motion without suffering another attack. La Notte mentions the case of a horse attacked when frightened by a sky rocket; Romer, the case of a horse scared by the sudden display of a white sheet in front of him, and Friedberger and Fröhner relate cases of attacks caused by intense rays of light, as in racing toward the declining sun, or the dazzling reflection from the surface of water. Liedesdorf saw it in a dog scared by a locomotive.

A strong impression like that caused by transition from bright light into darkness, by seeing shadows of trees crossing the road, or violent suffering caused by severe forms of constraint have been named as causes.

Speaking in “Brain,” of epilepsy in man, Alexander Haig attributes the fits to the fluctuations of uric acid in the blood. Headache (migraine) he finds to be very closely allied to epilepsy and convulsions and to be a result in a susceptible system of a liberal flesh diet. By a vegetable and fruit diet he reduces the ingestion and formation of uric acid, so that the largest quantity which a patient is likely to get into his blood, shall never or only very rarely, affect the blood pressure and increase the intracranial circulation to a dangerous extent. In predisposed subjects, all flesh food, soup, and meat extracts must be avoided, while even tea, coffee, cocoa and other vegetable articles containing xanthin compounds are to be regarded as producing uric acid, and to be denied, or employed only as the merest flavoring.

This position is greatly strengthened by the fact that epilepsy is so much more frequent in the carnivora (dog, cat, bird) than in the herbivora. It also suggests very strongly a light vegetable diet for both prophylactic and curative purposes in our domestic animals. In the same line the frequent and liberal drinking of warm water, the use of diuretics and the flushing of the large intestine are indicated.

For other causes see under pathology.

Symptoms in the =Horse=. It has been claimed that premonitory symptoms, such as dullness, lack of energy and quick, nervous or startled movements herald an attack, but in animals as in man, the disease usually attacks suddenly without any antecedent indication.

If at work the horse stops suddenly, or if in the stable he ceases eating, seems frightened, stands for an instant immovable, braces his feet, sways, trembles, and falls heavily to the ground. Or he may remain for an instant supported on his rigid limbs, the jaws moving or firmly closed, the eyes rolling, and the facial muscles drawn or twitching. When down there are convulsive movements of the limbs, so that the animal may kick out violently, and tense contractions or twitchings may occur in the muscles of the croup, chest and abdomen. There is usually an increase of the salivary secretion with frothy accumulation about the angles of the mouth. The respiration is stertorous, dyspnœic, and interrupted, the nostrils widely dilated, the nasal mucosa of a dark brownish red, and the superficial veins distended. The pulse is weak, slow, irregular, intermittent and sometimes imperceptible. Sensation seems to be in abeyance. No attention is paid to loud sounds, nor to pinching, pricking, or even cauterizing the skin. Perspirations may break out on the flank or over the whole surface of the body.