Definition. Susceptibility by genera, horse, dog, ox. Enterocele,
epiplocele, gastrocele, hepatocele. Congenital, arrest of development
and of closure of foramen or elsewhere, diaphragm absent. Traumatic,
blows on false ribs by pole, shaft, buffer, gate, bars, beams, kicks,
blows with horns, tusks, clubs, fractured rib perforating diaphragm,
falls on projecting bodies, muscular strains in draught, plunging,
falling, slipping, casting, parturition; trotting or galloping down
hill, jumping to lower level, slipping to knees, dystokia, colic,
tympany. Symptoms: extreme dyspnœa and asphyxia; or difficult
breathing slowly increasing, colics, dilated nostrils, retracted angle
of mouth, projecting eyeballs, shallow, rapid catching respirations,
gurgling in chest, drumlike percussion sounds, with perhaps flat
areas; in slight cases, listlessness, colics, double lift of flank,
tender intercostals; in chronic cases, short wind on exertion,
sluggishness, colics after meals. Hernia through intercostal space.
Lesions: unduly large foramen sinistrum or dextrum, lacerations of all
forms and sizes, edges ragged, thickened, bloody, broken rib, inflated
stomach causes shreddy tear; post mortem lacerations show no
inflammatory products; chronic cases have edges devoid of inflammation
and often smooth, serosæ usually perforated, nature of hernial mass,
omentum, intestine, colon, cæcum, stomach, spleen, liver, congestion
of viscera involved. Prognosis: slight cases may survive, to be
fattened or to breed, but are useless for work. Treatment: quiet,
sedatives, antiferments, cathartic, concentrated food, lift by fore
limbs, incline stall backward and downward, laparotomy in cattle,
dogs, and swine.
As this lesion is shown by symptoms referable to internal organs only,
and as it is considered irremediable by surgical measures, it may be
properly considered in the class of medical affections.
_Definition._ A displacement of one or more of the abdominal organs into
the cavity of the thorax.
_Frequency in different animals._ It has been found most frequently in
the horse, and less so in the dog and ox. Severe exertions conduce to it
in horse and dog, while in the ruminant the great bulk of the gastric
cavities, covering the whole posterior surface of the diaphragm, tends
to prevent protrusion even if a slight rupture has taken place. On the
other hand, the weight of the gastric cavities in the ox and the tension
upon the œsophagus, when the animals ride each other, sometimes cause
laceration of the foramen sinistrum and hernia of the reticulum.
_Hernial mass in different animals._ In the horse the protruding organ
is most commonly the small intestine (enterocele), omentum (epiplocele),
colon, or less frequently the cæcum, stomach (gastrocele), or liver
(hepatocele). In the ox the reticulum most commonly protrudes, and after
that the liver, abomasum, the omentum or the small intestine. In the dog
the mass is usually formed by the stomach or liver, or less frequently
by the small intestine or omentum.
_Causes and mode of formation._ The hernia is either congenital or
acquired after birth. Again, it may result from imperfect development or
from a trauma. Congenital cases usually depend on an arrest of
development, the foramen sinistrum fails to close and the abdominal
organ passes through by the side of the œsophagus into the chest; or the
diaphragm is left imperfect at some other point, and the two cavities,
abdominal and thoracic, communicate. In some instances there is left not
a distinct opening but a mere relaxation of the parts and under
traction, as, for example, by the gullet, an orifice is torn and a
hernia protrudes. Such cases are very rare. Other lacerations may be
almost all referred to external injuries on the posterior ribs, violent
muscular exertions, sudden shocks in connection with falls, or throwing
for operations, and overdistension of the abdominal viscera.
=1st. External Violence.= In the larger animals this may come from blows
on the last ribs, by poles or shafts of carriages, the buffers of cars,
the end of a gate and the gatepost, projecting ends of bars or beams
against which they run, kicks by horse or ox, blows by the horns of
cattle or tusks of boars. In the smaller animals in addition to the
above, blows with heavy clubs and kicks with heavy boots. In all such
cases there is usually a fracture of one or more ribs, the sharp broken
ends of which are forced into the diaphragm, which they tear when they
again spring outward. The same occurs as the result of falls on hard
projecting bodies of any kind.
=2nd. Muscular Strain.= In heavy draught the fixing of the glottis, ribs
and diaphragm and the extreme contraction of the abdominal muscles often
lead to extraordinary tension of the muscular septum by the mere
violence of which, or when there is superadded a sudden shock, (in
plunging in harness, or displacement of the feet or slipping and
falling,) the diaphragm is torn, usually in its tendinous portion, and
the abdominal viscus protrudes into the chest. If the diaphragm is
momentarily relaxed the lesion may take place in the peripheral muscular
portion. In still other cases the lesion is at one of the natural
openings. The same accident occurs in animals thrown for operation, the
abdominal viscera being full, the hind limbs drawn forward so as to
further compress the belly, and the muscles being subjected to violent
contraction in the efforts to get loose. Violent straining in dystokia
is another cause which, however, usually partakes of a sudden shock on
the diaphragm when a violent pain sets in.
=3rd. Sudden Shocks on the diaphragm, and pressure by the abdominal
organs.= In the horse especially the weight of the abdominal viscera is
very great and the floor of the abdomen inclines downward and forward so
that the whole mass presses with great force against the concave
diaphragm. In cattle the great weight of the stomach and liver is
especially important and in dog and pig of the liver mainly. In trotting
or galloping down hill or jumping from a higher to a lower level, or in
slipping back on the fore feet so that the horse falls on the knees or
shoulders, this pressure is suddenly greatly enhanced and the tense
diaphragm may give way in its tendinous portion or the relaxed organ
through its muscular tissue. A similar danger attends on the violent
straining which attends on difficult cases of parturition, and even in
cases of overloaded stomach and tympany and especially when the tortured
animal throws itself suddenly and recklessly on the ground. In cattle
and sheep this is usually the result of tympany of the rumen, and in
solipeds of stomach and intestines.
Rupture by simple overloading or overdistention is, however, a rare
occurrence, and many cases attributed to this are in reality instances
of _post mortem_ lesions, to be identified by the seat of the laceration
in the muscular portion, and by the absence of blood clots, exudate,
thickening or other sign of inflammation on the torn border.
_Symptoms._ These bear a direct relation to the size of the laceration
and the mass of abdominal organs that protrude into the chest.
In _very grave, recent cases_, with a great phrenic rupture and a most
extensive protrusion of abdominal organs into the chest, there may be
simply the indications of extreme dyspnœa, nostrils and chest widely and
persistently distended, nasal mucosa darkly congested, countenance
pinched, eyes protruding and fixed, pupils dilated, breathing rapid,
shallow and oppressed, and in a few minutes the animal staggers and
falls in the death agony.
In _cases_ which are _less rapidly fatal_, the patient lasting for hours
or even days, there occurs, after the accident, deep, difficult and
oppressed breathing, but not so violent as to threaten instant
suffocation, or more commonly, these symptoms increase slowly as more
and more of the hernial mass protrudes through the narrow opening into
the chest. This form is usually seen only in animals of a specially
quiet disposition, and which have not been subjected to active exertion
or excitement after the accident and the hernia has increased by slow
degrees only. The patient becomes listless, or very restless, paws,
looks at his flanks, shifts from one hind foot to the other or even
kicks at the abdomen, lies down carefully, rolls, sits on his haunches
(though no more than in other forms of colic), and manifests the
anxious, pinched, colic-countenance. The advance of the pain is constant
but slow, and usually it is not characterized by that intensity which
drives the animal to throw himself down recklessly and to roll and kick
with violence. There is also usually an absence of the weak running down
pulse of hemorrhagic congestion (thrombosis) and of the pallor of the
surface mucosæ which usually attend on the extensive blood
extravasations of that disease. An exception may be made in those cases
in which the hernial mass is strangulated, as these may closely resemble
spasmodic colic or hemorrhagic congestion.
The respiration furnishes more distinctive symptoms. The breathing which
may be hurried and almost panting in colic and acute congestion, is
changed in this lesion to a condition of extreme oppression, the
nostrils remain widely dilated in expiration as well as inspiration, the
angle of the mouth is retracted so as to show the teeth and gums, all
the facial muscles stand out, the eyes are protruding and fixed, with
dilated pupils, the head is held extended on the neck, and the ribs are
not allowed to fall in freely, as after ordinary inspiration, but like
the nostrils they remain permanently drawn out. The efforts at
inspiration are violent though shallow and marked by lifting of the
flanks. There are usually one or two nervous catches in each expiration
and sometimes in inspiration as well. This is partly due to the
impotence of the deeply lacerated diaphragm as an organ of respiration,
but also to the pressure of the displaced and overdistended abdominal
organs on the lungs, and to the profound nervous shock. The whole work
has been suddenly thrown on the costal muscles, and the depressed
nervous system proves unequal to sustaining them in the unwonted toil.
Still clearer indications may be obtained from auscultation and
percussion. These are gurgling, rumbling and clucking, or a coarse
mucous râle which seem abnormally close to the ear, and a drumlike
resonance, much greater than that of emphysematous lung and enormously
in excess of what is given out by the sound lung tissue. These may be
heard at points where only pulmonary murmurs naturally occur or where
abdominal sounds, if heard at all, are distant in health. There may also
be areas of abnormal flatness on percussion by reason of the protrusion
of a solid viscus like the liver or spleen or one with solid contents.
These symptoms are only clear when there is a large intrusion of
abdominal organs into the thorax, and they increase rapidly until
asphyxia supervenes.
In _cases which do not immediately threaten life_ the extent of the
phrenic laceration is usually small and the orifice may be blocked by a
bulky organ like the rumen, double colon, stomach or liver, so that any
protrusion takes place only to a limited amount and the function of the
diaphragm can still be carried on to a reasonable extent. In these cases
there may be no very marked symptom at the outset, though the animal is
dull, listless and without appetite, or, if he eats or drinks, it is
liable to be followed by slight colics and a double action of the flank
in expiration as in pulmonary emphysema (heaves). Pressure or percussion
in the posterior intercostal spaces is painful. Cough when roused by
pinching the larynx is broken and abortive. These symptoms are not
distinctive, however, and unless there is a protrusion of a loop of
small intestine, to give gurgling and drumlike sounds the diagnosis of
the case is liable to fail. The fact of a recent injury may however
assist in the recognition of the lesion.
The _chronic cases_ are even more difficult to recognize as there is no
record of recent injury and no fever. There may be _short wind_, the
animal breathing hurriedly on slight exertion, and showing a double lift
of the flank in expiration (Girard). In place, however, of the
tympanitic bowels and frequent passage of flatus which characterize
heaves, there is a tendency to colic, especially after meals, and in a
certain number of cases there are all the symptoms of fatal
strangulation, due to the contraction of the diaphragmatic wound. When
the hernia is made by a loop of intestine there are the characteristic
symptoms of thoracic gurgling and drumlike resonance.
Cases are on record in which the intestine protrudes through one of the
last intercostal spaces or between the ends of the broken rib as a
hernia and diagnosis becomes easy by auscultation, palpation and
percussion. But in a large proportion of cases the lesion escapes
recognition and is only found on _post mortem_ examination.
_Lesions._ The lacerated orifice in the diaphragm varies much as regards
situation, extent, form and the nature of its border. In congenital
cases due to an imperfect closure of the natural openings there may be
simply a round or ovoid opening, too spacious to be filled by the
gullet, vena cava or aorta as the case may be, and capable in the
different cases, of containing an organ of any size from the omentum to
the liver or stomach. Its margins may be perfectly smooth and even,
without any thickening, irregularity, fringe, clot or exudate. In
traumatic cases on the other hand the orifice may be of almost any form,
size or situation. It may be round, elliptical, triangular, or irregular
in many ways. It may be so small as to admit nothing more than a small
fold of the omentum, or it may be large enough to open the two cavities,
thoracic and abdominal into one common space, and to practically abolish
the function of the diaphragm. If the lesion is a recent one the torn
margin is irregularly indented or fimbriated and marked by small black
blood clots, and somewhat later by exudate and irregular thickening or
swelling. When due to a broken rib, the existence of the fracture is
patent and the laceration extends along two lines often radiating from
point of perforation by the rib. When the laceration has resulted from
tympany of the stomach or intestines or from other overdistension of the
abdominal organs, the general and comparatively equable pressure has
determined the independent laceration of numerous tendinous or muscular
bundles all over the diaphragm, so that the divided ends stand out at
intervals each bearing its little clot of dark blood, but without actual
perforation. The actual orifice in such cases is confined to one point
where the tension has been greater or the resistance less. _Post mortem_
lacerations, from tympany or other cause, are easily distinguished from
those occurring during life, in that the edges of the wound are pale and
bloodless, without clot or exudate.
When the hernia is chronic there is an absence of exposed fringes, and
of indications of inflammation, the margins of the orifice being in some
cases smooth, even and fibrous, and in others irregularly notched or
indented with nodular, fibroid swellings of various sizes at intervals.
In such cases the orifice is always relatively small and the hernial
mass inconsiderable.
As a rule the peritoneum and pleura, being firmly adherent to the
diaphragm, are involved in the laceration so that the hernial mass is
not retained in a special sac, but simply protrudes into the pleural
cavity, after the manner of an eventration. In exceptional cases they
become detached from the muscle, and becoming distended, envelope the
hernial mass in a distinct sac.
In hernia with a very small orifice the omentum alone may pass through,
even the small intestine proving too large for admission. In such cases
it is usual to find the band of omentum adherent to the callus formed by
the repair of a fractured rib. When the orifice is somewhat larger a
portion of small intestine or of the double colon or cæcum may be
engaged, while with a still larger opening the stomach, spleen, or liver
may form the hernia. In cattle the reticulum is most likely to be the
hernial mass, as noted in an article below. In rare cases the small
intestines, omentum or liver protrude (Youatt, Lafosse). The protruding
organ is liable to be constricted and strangulated sooner or later by
increase in its bulk in connection with its vermicular movements, the
accumulation of its contents or the extrication of gas in its lumen, or
by the gradual contraction of the orifice in process of healing. Then
there may be dark red venous congestion, blood extravasation and
effusion, friability and even rupture of the intestinal walls, and
adhesions to the wound or the lungs. Once started this congestion and
extravasation may extend backward into the abdominal cavity involving a
great part of the contiguous intestinal canal.
_Prognosis._ The worst cases are promptly fatal, while others destroy
life in one or two days and such are always to be recognized by the
extreme dyspnœa which appears soon after the accident. The slight cases
with small orifice and little protrusion may merge into the chronic
form, and the animal may even be fit for work, notwithstanding existing
dyspnœa, which closely resembles that of chronic emphysema (heaves), but
is not benefited by the same treatment. In the ruminants even
considerable lacerations and protrusions may not be incompatible with
fattening provided the animal is kept from all causes of excitement or
over-exertion.
_Treatment._ Surgical treatment has not proved successful. Expectant and
medicinal treatment are the only available resorts and then only in the
slighter cases. Quiet and the absence of all excitement is the first
consideration to allow of an arrest of any increase of the hernia and
the establishing of a healing process in the torn margins. Bouley
strongly advises bleeding to allay abdominal pain. Chloral hydrate (1
ounce for the larger animals) will often meet the same end, with the
additional advantage that it counteracts fermentation and tympany. The
unloading of stomach and bowels by a cathartic, and the use of flaxseed
meal or other concentrated food of a laxative nature are indicated.
Small animals may be lifted by their fore limbs, and the abdomen may be
meanwhile manipulated to favor the return of the hernial mass by
gravitation. Large animals should be placed in a stall having an
inclination downward and backward for the same reason. When it can be
ascertained that the hernia consists of a loop of small intestine only,
it is permissible, especially in cattle, carnivora and omnivora, to make
an incision in the flank and with the disinfected hand to attempt the
reduction of the hernia and the placing of a bulky viscus, like the
rumen, stomach or liver in the way of its return. In case of violent
abdominal pain Bouley advises active counter-irritation over the
abdomen, but as strangulation is usually present in such cases, this
measure may be held to be inferior in value to gravitation, anodynes,
antiseptics, unloading of the gastro-intestinal organs and absolute rest
or surgical interference.