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.
Friedberger and Fröhner found apoplexy quite frequent in sheep, ox. and
dog, and rare in the horse, although more subject to the violent
exertion which they put in the front of all causes. It is probable that
the sluggish, pampered life of the first three animals, and the tendency
to fatty degenerations and heart disease introduces a special
predisposition as it does in man, while the horse, inured to an open air
life and a vigorous muscular condition, is comparatively immune.
Bright’s disease is a common cause in the human subject, with its
resulting cardiac hypertrophy. The degenerations attendant on these
conditions and especially fatty change (atheroma) in the walls of the
cerebral arteries, pave the way for their rupture and for blood
effusion. Emboli also carried from the diseased heart not only cut off
the blood from the parts supplied by the plugged arteries, but increase
the blood tension on the cardiac side of the obstruction and endanger
rupture at any weak part. Thus they may cause apoplexy from anæmia
without rupture or apoplexy from the pressure of effused blood.
=Age= which is such a notorious factor in man is not without its
influence in the lower animals. It is in the old that we mostly see
disease of kidneys and heart and the degenerations of the tissues,
including the brain and its vessels; in these, therefore, rupture and
extravasation are the most frequent.
The other causes are mostly connected with increased blood tension with
or without a debility of the vascular walls. Violent exertions as in
racing, coursing, dragging heavy loads up hill or on heavy ground,
severe excitement, cerebral concussion, insolation, and intense
congestion of the brain substance have all been recognized as causative
factors. The compression of the jugulars by a small collar, the violent
straining attendant on parturition, or constipation, and even the
retrocession of blood from the surface when exposed to extreme cold, may
contribute to the final rupture.
In infectious diseases in which the toxic products tend to produce
profound modifications in the blood and tissues, extravasations are met
with in the brain as in other organs. Thus they are seen in anthrax,
Texas fever, petechial fever, etc.
Then the formation of =neoplasms= in the brain may be the occasion of
the rupture of the vascular walls and apoplexy. =Hæmatoma= of the dura
in the dog (Friedberger and Fröhner), =cholesteatomata= in the horse,
and =carcinoma= may be apparent causes.
The effect of =mechanical injury= must be admitted, as blows on the
head, injuries from an ox yoke, and concussions during the battles of
rams and bulls.
_Lesions._ Blood extravasations may be found at any part of the brain:
a. into the brain substance; b. into the ventricles; c. from the pia
mater; d. into the arachnoid sac; e. between the skull and dura mater.
It is especially common in connection with the ganglia adjoining the
ventricles; the corpus striatum, optic thalamus, the corpora
quadrigemini, the fornix. In other cases the crus cerebri, pons, medulla
oblongata, corpus calosum. In other cases the convolutions of the
cerebrum or cerebellum suffer. The amount of effusion may be limited to
a few drops or it may cover an extensive area and cause considerable
flattening of the brain substance.
When capillary hæmorrhages are present—the size of a millet seed or a
pea—Friedberger and Fröhner have usually found them multiple, but when
large enough to form distinct clots they are usually single and confined
to one side. If a clot, involving the brain substance, is small, it
merely separates the nervous fibres, but if larger, the cerebral tissue
is broken down in the mass of clot, discolored, torn and softened. If
the patient has survived the first attack the clot passes through the
different stages of discoloration, brown, brownish yellow, yellow, and
may become fibrous forming a distinct cicatrix, with loss of brain
substance. In connection with the partial absorption of the effused
blood, cavities may be filled with a serous fluid (apoplectic cysts),
and these may show multiple loculi. The nerve fibres which lead to an
old standing lesion are usually degenerated.
When effused into a ventricle, blood is less readily absorbed and tends
to remain as a flattened discolored layer.
Extravasation between the dura mater and the cranium is probably always
the result of direct mechanical violence.
_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.
Congestion of the encephalon is treated here as a pathological entity,
though it cannot always be distinguished clinically from some forms of
vertigo on the one hand and from the milder types of apoplexy or
encephalitis on the other. It has been divided into _passive_ or _venous
hyperæmia_ and _active_ or _arterial hyperæmia_.
_Passive hyperæmia_, as shown under vertigo and apoplexy is a common
result of a tight collar, a tight strap used for cribbiting, a too short
bearing rein, dilation or valvular disease of the right heart, or
disease of the lungs, violent efforts in running, draught, etc. It tends
to be associated with arterial anæmia on the principle that the closed
cranial cavity can only admit a certain amount of blood and if an excess
accumulates in the veins and capillaries, this must be compensated first
by the movement backward to the spinal canal of the cerebro-spinal
fluid, and second by the diminution of the blood in the cerebral
arteries.
_Active hyperæmia_ may be brought about by any excitement which
especially affects the brain. This has been already noted in connection
with insolation (sun-stroke). It may result from severe exertion during
hot weather, in a violently contested race, in drawing a heavy load up
hill, or in harsh training. Violent exertion just after a meal is
especially injurious. Also the excitement of travelling by rail, or that
caused by proximity to locomotives, to discharges of firearms and to
other causes of great fear; encreased blood tension in the cerebral
vessels in connection with hypertrophy of the left ventricle, or
obstruction in other vessels (of the limbs) so as to direct the force of
the current into the carotids, the expulsion of blood from the
splanchnic cavities by gastric or intestinal tympany, or overloading of
the paunch, and irritation of the brain by ptomaines and toxins in
certain infectious diseases (rabies, canine distemper, etc.). In the
same way vegetable narcotics (opium, etc.) produce congestion. Among the
most common causes of congestion are lead, poisoning by lolium
temulentum, partially ripened lolium perenne, millet, Hungarian grass,
and partially ripened seeds of the leguminosæ (chick vetch, vicia
sativa.). Other causes are the presence of tumors (cholesteatoma) and
parasites (cœnurus, cysticercus) in the brain.
_Symptoms._ Cerebral hyperæmia, like other brain disorders may give rise
to a great variety of symptoms, according to the condition of the animal
and the susceptibility of its nerve centres. Some cases have the
characteristic seizures of vertigo, others the manifestations of heat
stroke, and others, epileptic explosions or apoplectic symptoms. For
these see under their respective headings. In other cases the symptoms
are those of encephalo-meningitis but moderate in its type and often
tending to a transient duration, or to prompt resolution and recovery.
=Horse.= There is manifest change of the nervous and intellectual
conditions, which may show itself by irritability or restlessness, by
pushing against the wall, by hanging back on the halter, by trembling,
shaking the head, neighing, pawing and, in exceptional cases, by
rearing, biting or kicking. The pulse is hard and full, the heart’s
impulse strong, the beats in the carotids and temporal arteries being
especially forcible, and the buccal, nasal and orbital mucosæ are
strongly congested. Heat of the head is usually a marked feature. While
usually very sensitive to touch, noise or light, the animal may be dull
or drowsy, and in spite of its marked sensitiveness, it is then inert or
lethargic and indisposed to any active exertion. Freidberger and Fröhner
say that the habitual comatose condition alternates at intervals with
periods of violent excitement during which the animal pushes or dashes
against the wall, grinds the teeth, rears, paws, kicks, bites, etc., and
then relapses into the state of coma. When the disease reaches this
stage it may be questioned whether we are not dealing rather with acute
encephalitis.
In active congestion the symptoms are always aggravated by whatever
tends to increase the vascular tension in the brain. Active exertion,
draught, the pendent position of the head, the recumbent position on the
side with the head as low as the body or lower, aggravate all the
phenomena and render the animal more helpless.
The following table slightly modified from Spitzka serves to point out
the distinctions between anæmia and hyperæmia:
─────────────────┬─────────────────┬─────────────────┐
Symptoms. │ In Cerebral │ In Cerebral │
│ Anæmia. │ Hyperæmia. │
─────────────────┼─────────────────┼─────────────────┤
│ │ │
Pupils. │Usually dilated │Usually small or │
│ and mobile. │ medium. │
Respiration. │Often interrupted│Normal or nearly │
│ by a deep │ so. │
│ breath or sigh,│ │
│ even when at │ │
│ rest. │ │
Activity. │Lassitude. │Restless, but │
│ │ indisposed to │
│ │ exertion. │
Temperament. │Lethargic with │Irritable with │
│ exceptions. │ exceptions. │
Intelligence. │Senses impaired. │Impaired. │
Elevation of │Aggravates │No effect, or │
head. │ symptoms. │ improvement. │
Recumbent, │Amelioration. │Aggravation. │
dependent head.│ │ │
Straining. │Not necessarily │Aggravated. │
│ aggravated. │ │
─────────────────┴─────────────────┴─────────────────┘
=Cattle= show the same general congestion and heat of the head, ears and
horns, congested mucosæ, fixed eyes, and pupils, indisposition to follow
the herd, irritability, and dulness with often a disposition to lie
down. This may go on to violent bellowing, pushing against the wall,
grinding of the teeth, working of the jaws, rolling of the eyeballs, and
violent dashing in different directions regardless of obstacles.
=Dogs= show the same restlessness and excitability, congested head, eyes
and nose, frequent movement from place to place, a desire to wander off,
and it may be spasms. If there has been any gastric disturbance vomiting
usually supervenes. As in the larger animals the disease may go on to
more violent symptoms, and the animal howls, rushes in different
directions, and may snap at imaginary objects, or at any one who
interferes with him. His movements are liable to be unsteady, uncertain
and swaying.
In all cases the ophthalmoscope reveals a congestion of the optic disc.
In the different animals too, acute cerebral hyperæmia tends to merge
early into encephalitis with exudation and pressure, attended by stupor,
coma, somnolence or profound lethargy.
_Treatment._ In slight cases of cerebral hyperæmia, it may be sufficient
to apply cold to the head with a stimulating fomentation to the limbs,
and an active purgative, with chloral or bromides. Ergot in full doses
has often an excellent effect.
In the more acute types of the disease, bleeding is the first and most
efficient measure. A full abstraction from the jugular will relieve the
vascular tension and relieve the circulation on the brain. It has been
counselled to avoid this when comatose symptoms have set in, and in some
prostrate conditions a large and rapid abstraction of blood may fatally
increase the prostration. In other cases, however, the less rapid
abstraction will improve at once the intracranial circulation and
nutrition, and solicit the reabsorption of the exudate which produces
sopor and coma.
A purgative is one of the most efficient derivatives, the determination
of an excess of blood to the bowels and of an abundant serous discharge
into their interior acting as a valuable depletion, and abstraction of
blood from the over-excited brain. At least a half more than the usual
dose must be given, and may be supplemented by an injection of glycerine
or a hypodermic exhibition of eserine. It is best to avoid too drastic
or irritant purgatives as the cerebral congestion may be aggravated by
the irritation, as it often is induced in severe indigestions. For the
horse, aloes and podophyllin, or for ruminants, omnivora and carnivora
castor oil may be resorted to.
The patient must be placed by himself in a dark, cool, well aired
building, and when able to resume feeding must receive an easily
digested, non-stimulating diet; for horses or cattle gruels, wheat bran
mashes, pulped roots, or green food; for dogs and pigs, gruels, mush or
milk.
Any sequent paralysis must be treated on general principles.