Diaphragmatic Hernia in Horses in Israel: A Case Series

March 21, 2015 — admin
Filed under:
AttachmentSize
equin_hernia.pdf1.72 MB
Embedded Scribd iPaper - Requires Javascript and Flash Player

Israel Journal of Veterinary Medicine  Vol. 70 (1)  March 2015 37 Diaphragmatic Hernia in Horses
INTRODUCTION
Diaphragmatic hernias (DH) are classifed as true, having a
hernia sac, or false where this is a lack of a hernia sac. False
hernias can probably be better defned as a diaphragmatic
defect, rupture or tear (1). Nevertheless, in order to conform
to the current literature the term DH will be used throughout
the manuscript for consistency. A further classifcation takes
into account the etiology of DH, namely congenital and
acquired. Te congenital form is mostly associated with an
abnormal development of the various parts of the diaphragm,
which do not fuse together, while the acquired form is usu-
ally caused by trauma or increased intra-abdominal pressure
(e.g. parturition (1, 2)). Congenital as well as acquired DH
are typically left-sided (1, 3), though a right sided congenital,
Morgagni type DH has been also reported (4). Interestingly,
there is an in-between form that can be defned both as
traumatic-acquired and as congenital. Tis form of DH oc-
curs upon parturition in which the foal’s ribs fracture and
tear its diaphragm upon passing through the birth canal (5).
Te location of the defect in the diaphragm varies, but it
most commonly occurs at the junction between the tendine-
ous and the muscular parts of the diaphragm. Te location of
Diaphragmatic Hernia in Horses in Israel: A Case Series
Efraim, G.* and Kelmer, G.*
Large Animal Department, Veterinary Teaching Hospital, Koret School of Veterinary Medicine, Te Robert H. Smith Faculty
of Agriculture, Food and Environment, Te Hebrew University of Jerusalem, Israel.
*
Corresponding Author: Dr. Gal Kelmer, Large Animal Department, Koret School of Veterinary Medicine, Te Robert H. Smith Faculty of Agriculture,
Food and Environment, Te Hebrew University of Jerusalem, PO Box 12, 76100, Rehovot, Israel.Tel: +972-(3)-9688588, Fax: +972-(3)-9688525, Email:
gal.kelmer@mail.huji.ac.il
ABSTRACT
Diaphragmatic hernia (DH) is possibly more frequent in the horse than typically reported in the literature.
Since DH is not as rare as perceived, reporting on its occurrence is critical in order to increase awareness
of this problem. DH typically presents as an emergency situation, whose prompt treatment infuences the
prognosis. Tus, it should be included in the diferential diagnosis of horses presenting with signs of colic
or of respiratory distress, or with a combination of the two. Te aims of this study were to determine the
prevalence of DH cases at the Veterinary Teaching Hospital of the Koret School of Veterinary Medicine
and to describe the clinical signs, case management and outcome of these cases. Te equine medical records
of our hospital for January 2008 – August 2012 were reviewed. Te information retrieved included chief
complaints, mode of diagnosis, physical characteristics of the hernia, organs found in the thorax, treatment,
results and, where relevant and pathology report. Te number of DHs was compared to the hospital’s caseload
and colic surgeries during the reference period. Four horses were presented with DH in the reference period
constituting 0.46% of all surgeries and 1.29 % of all colic surgeries in the reference period, and 0.14% of the
annual referral fgure. Tree of the four cases showed signs of colic with respiratory symptoms, whereas the
fourth presented only acute respiratory distress. Te survival rate was 25%, one patient being successfully
treated. Te prevalence of DH was found to be more frequent at the KVSM-VTH than previously reported.
Early diagnosis and a suitable surgical approach proved essential to the successful surgical repair of DH, but
the overall survival rate remained low.
Keywords: Diaphragmatic Hernia; Equine; Prevalence; Respiratory Distress; Colic.
Israel Journal of Veterinary Medicine  Vol. 70 (1)  March 2015 Efraim, G. 38
the lesion is probably afected by the nature of the etiologic
factor (1). Te organs that are usually incarcerated in DH
are the small and large intestines (1, 2, 6), but the spleen, the
stomach and the liver can also be involved (2).
All types of DH can remain subclinical for prolonged
periods and clinical signs typically appear acutely upon
incarceration or strangulation of intestine. Clinical signs
are typically signs of colic, but may include and limited to
respiratory distress (7). Symptoms however may be mild,
such as lethargy and exercise intolerance alone, up to a stage
when organs migrate into the thoracic cavity. Initial suspicion
of DH can be established following physical examination,
when signs of colic are accompanied by respiratory distress.
Other, inconsistent, non-specifc, signs include resistance
upon nasogastric intubation and a sensation of emptiness
upon rectal palpation. Useful diagnostic techniques include
thoracic radiographs and ultrasonographic evaluation (1).
Notwithstanding, diagnosis is unfortunately often reached
only by exploratory celiotomy or post-mortem examination
(2).
Treatment is exclusively surgical and aims at removing the
herniated bowel from the thorax, with or without resection,
and repairing the diaphragmatic defect (8). Post-operative
treatment should comprise management of pneumothorax
and pleuritis in addition to the typical post-operative colic
treatment regimen.
Tis report describes the diagnostic procedures and
the treatment of four cases of DH which were recorded at
the Veterinary Teaching Hospital of the Koret School of
Veterinary Medicine (KVSM-VTH) during January 2008
– August 2012. Te study was carried out in order to better
understand DH prevalence and possibly assist improve future
treatment of similar cases.
MATERIALS AND METHODS
Tis article is a retrospective cohort study that was carried out
in the KVSM-VTH between January 2008 and August 2012.
Te clinical and clinical pathology records of the DH cases
recorded in the reference period were reviewed. Te clinicians
involved in the cases also assisted in the retrieval of informa-
tion regarding the clinical history, signalment, medical and
surgical treatment, and outcome for their respective cases.
Records were found for two fllies, a mare and a stallion,
aged 10 days, 7 months, 18 years and 17 years respectively.
Te main equine population seen in the hospital com-
prised riding and breeding horses. Te total number of cases
for each year was retrieved and an average case load per year
was computed. Te same calculation was performed for
the number of surgeries and colic surgeries at the hospital.
Te prevalence of DH was calculated in percentage terms,
along with the percentage of DH in total surgeries and colic
surgeries.
RESULTS
During the reference period, the KSVM-VTH received an
average of 67 surgical colics per year, and DH comprised
1.29% of our surgical colic caseload. Te KVSM-VTH, with
an average of 637 referrals per year over the reference period
( January 2008 –August 2012), received four horses with DH
during this time which amounted to 0.14% of the total refer-
rals. Only one of the four cases with DH survived (25%) to
discharge with a good long-term outcome.
CLINICAL CASES
CASE 1
Clinical History
A 10-day-old Arabian flly was presented to the KVSM-
VTH, after uneventful pregnancy and parturition. Te own-
ers reported having noticed signs of weakness and carpal
swelling on the right forelimb the following day. On arrival to
the hospital the complete blood count (CBC) revealed, WBC
of 6.3x10
9
/L, Reference Range (RI): 5.6-12.1x10
9
/L), packed
cell volume (PCV 37%, (RI): 27-43%) and total solids (TS)
of 6g/dl, (RI): 6-8g/dl) were within the reference ranges.
Sample of synovial fuid taken from the right inter-carpal
joint was consistent with synovial infection (TS 7g/dL, (RI):
2-3.5g/dl; lactate 8 mmol/L, (RI): 0-2 mmol/L; glucose 19
mg/dL, (RI): 76-130 mg/dL).
Case Management
Amikacin (20 mg/kg s.i.d., Vetmarket, Shoaham, Israel),
ampicillin (20 mg/kg q.i.d., Penibrin, Sandoz GmbH, Kundl,
Austria), funixin meglumine (0.5 mg/kg b.i.d., Norbrook
laboratories Ltd, Newry, N .Ireland) and LRS (Teva Medical,
Petah Tikva, Israel) were administered intravenously and
ranitidine (7 mg/kg t.i.d., Dexcel Pharma, Jerusalem, Israel)
was administered orally. Te next day the flly underwent
Research Articles
Israel Journal of Veterinary Medicine  Vol. 70 (1)  March 2015 39 Diaphragmatic Hernia in Horses
arthroscopic surgery under general anaesthesia. In both
the inter-carpal and the radio-carpal joints, pannus, syno-
vial edema and discoloration were found, consistent with
synovial sepsis. In both joints, pannus was removed, partial
synovectomy was performed, followed by generous lavage (12
liters per joint) and amikacin (1g) was injected. Te joints
were lavaged daily under heavy sedation (butorphanol (3
mg, Morphasol, Animedica GmbH, Senden, Germany),
diazepam (10 mg, Teva Medical, Petah Tikva, Israel) and
xylazine (10 mg, Sedazine, AST Farma, Oudewater, Te
Netherlands)) using teat cannulas, for 10 days. Since clini-
cal signs persisted despite the aggressive management, joint
lavage was replaced by regional limb perfusion (RLP) with
imipenem (Merck Sharp & Dohme, Chibret, France) alter-
nating with intra-articular injections with imipenem. Te
same day the flly exhibited difculty in expiration subsequent
to tranquilization. Dyspnea recurred the following day and
lateral thoracic radiographs taken in recumbent position
showed no evidence of a respiratory pathology.
After another RLP procedure carried out the same week,
the patient was kept under observation, with daily bandage
changes, as there was improvement in the condition of carpus.
During the third week of hospitalization, the flly’s lameness
and general condition improved, whereas acute respiratory
distress continued to fare up occasionally.
On day 23 of hospitalization, the flly developed severe re-
spiratory distress accompanied by tachycardia and tachypnea
(heart rate 120 beats/min and respiratory rate 56 breaths/
min). At that stage, the flly had a severe bout of coughing
and then collapsed in agonal breathing. An attempt was made
to insert an endotracheal tube, but the flly collapsed and
stopped breathing. Intubation was successfully performed
but resuscitation eforts were attempted to no avail, until
death ensued.
Post-mortem examination
Te post-mortem examination revealed: yellowish liquid
flling the thoracic cavity, the lung lobes were collapsed, and
discoloured, with consolidation in ~30% of the lung feld. In
addition, there was a 15 cm long defect in the right crus of
the mid-diaphragm at the border of the muscular and fbrous
portions of the diaphragm. Te margins of the opening were
thick. Multiple loops of the small intestine were found in
the thoracic cavity. Te dorsal loops appeared thickened and
compromised (Figure 1).
CASE 2
Clinical History
A 7 months old Arabian flly had had a history of severe
abdominal pain. Two days earlier the owner called the refer-
ring veterinarian to treat the flly for a ventral abdominal
swelling. Te veterinarian detected that the swelling included
the right-side thorax, and administered anti-infammatory
medication. Several hours before arriving to the hospital,
the flly showed severe signs of abdominal pain, which were
unresponsive to analgesics, and was referred to the hospital.
On arrival to the hospital Te flly was severely painful
and required potent analgesia in order to tolerate the initial
evaluation. A swelling was detected on the right hemi-
thorax and on the ventral part of the abdomen. Blood tests
included CBC: ( WBC of 4.2x10
9
/L, Reference Range (RI):
5.6-12.1x10
9
/L), packed cell volume (PCV 45%, (RI): 27-
43%) and total solids (TS 8.2g/dl, (RI): 6-8g/dl) were con-
sisted with mild dehydration and leukopenia. On ultrasound
examination, a portion of the small intestine with peristaltic
movement, and fractured ribs were visible in the swelling on
the right hemi-thorax. At that stage, the flly was submitted
for urgent abdominal exploration under general anaesthesia.
Case Management
Preoperative medication was administered intravenously as
follows: benzylpenicillin sodium (20,000 IU/kg, Norbrook
laboratories Ltd, Newry, N. Ireland), gentamicin (6.6 mg/kg,
Figure 1: Necropsy photograph of case 1, depicting diaphragmatic
hernia in a 10 days old Arabian flly. Vertical white arrow points to the
herniated small intestine while the horizontal white arrow points to
the torn diaphragm. Vertical black arrow points to the stomach while
the horizontal black arrow points to the collapsed lungs.
Research Articles
Israel Journal of Veterinary Medicine  Vol. 70 (1)  March 2015 Efraim, G. 40
Gentaveto, Eurovet, Netherlands) and funixin meglumine
(1.1 mg/kg). Te patient was then premedicated intravenously
with 100 mg xylazine, and induction was performed with 220
mg of ketamine (Clorketam, Vetquinol, Paris, France) and 10
mg of diazepam. Te flly was positioned in dorsal recum-
bency and isofurane (Piramal Critical Care, Inc, Bethlehem,
Pennsylvania, USA) was used to maintain anaesthesia.
A ventral abdominal midline approach was performed,
and small intestine entrapped in a diaphragmatic tear,
were observed. Te diaphragmatic tear was about 10 cm
long, located on the right ventral muscular portion of the
diaphragm (Figure 2). After carefully reducing the incarcer-
ated intestine into the abdominal cavity, it was found to be
non-viable. Over 70% of small intestine was discolored and
had no pulse or motility with several tears in the mesentery
(Figure 3). In addition, the right hemi-thorax had a large
defect that contained some of the damaged intestine, and four
sharp-edged fractured ribs 12-15. Te ribs were fractured at
the costo-chondral junction. Tere was no external wound,
neither at the thorax nor caudally, but the ribs lacerated the
thoracic wall allowing several loops of small intestine to
migrate subcutaneously. Due to poor prognosis the flly was
euthanized at the owner’s consent.
CASE 3
Clinical history
An 18 year-old mixed breed mare sufered from colic which
had begun about twelve hours earlier and had responded well
to the initial analgesic therapy in the feld. Nevertheless, a
few hours later the mare showed severe signs of colic and was
referred to the hospital. On arrival at the hospital the mare
had severely compromised cardiovascular status with marked
tachycardia (100 beats per minute), hyperemic mucous mem-
branes and cold extremities. Auscultation revealed decreased
borborygmus and nasogastric intubation produced 13 liters of
refux. On rectal examination, dry feces and a gas-distended
large colon were felt. A CBC revealed a high WBC count
(15.4x10
9
/L, RI: 5.6-12.1x10
9
/L) and elevated PCV, indicative
of hemoconcentration (PCV 48%, RI: 27-43%), while TS was
low (4.7 mg/dL, RI: 6-8mg/dL), and lactate concentration was
elevated (5.1 mmol/L, RI: < 2 mmol/L). During examination,
the mare showed signs of uncontrollable pain and immediate
exploratory celiotomy was therefore uninitiated.
Case Management
Preoperatively the mare was given sodium penicillin G
(20,000 IU/kg) and gentamicin (6.6 mg/kg) intravenously.
Te mare underwent induction and isofurane and anaesthe-
sia. With the mare in dorsal recumbency, a ventral midline
abdominal approach was performed. Exploration revealed a
defect in the diaphragm, about 22-cm long, situated in the
left dorsal part of the diaphragm, at the musculo-tendinous
junction. Te stomach, several meters of the small intestine,
the pelvic fexure and a left lobe of the liver were incarcerated
in the thorax. Furthermore, a large colon volvulus was found
(360° counter-clockwise). Te cecum and the large colon were
edematous and purple. Part of the omentum was adhered
Figure 2: Intra-operative photograph of case 2, depicting a
diaphragmatic tear in a 7 months old Arabian flly. Te image is viewed
through an abdominal approach for exploratory celiotomy.
Figure 3: Intra-operative photograph of case 2, depicting torn
mesentery and damaged small intestine in a 7 months old Arabian
flly sufering from diaphragmatic hernia. Te arrows points to the
extensive tear in the small intestine mesentery.
Research Articles
Israel Journal of Veterinary Medicine  Vol. 70 (1)  March 2015 41 Diaphragmatic Hernia in Horses
to the lateral border of the hernia. Te abdominal organs
were retrieved and returned in their normal position in the
abdominal cavity. Te volvulus was manually corrected, which
led to an improvement in color and motility of the large
colon. Te omentum was ligated and resected. A blood gas
analysis performed an hour after induction showed respira-
tory acidosis (with values of 102.9 mm Hg for PaO
2
, (RI:
100-500 mm Hg) 50 mm Hg for PaCO
2
(RI: 30-45 mm Hg)
and 7.26 for blood pH (RI: 7.35-7.45), which was resolved by
having the mare tilted 30 degrees head up (reverse trendelen-
burg position) for an hour in order to decrease the pressure
exerted on the lungs by the abdominal organs. Attempts to
correct the hernia through the abdominal cavity failed. Te
deep dorsal location and considerable tension on the sutures,
due to the large gap in the diaphragm; combined with the
friable diaphragmatic muscular tissue; hindered the repair.
Te abdomen was lavaged and closed in a routine fashion.
At that stage the mare was positioned in right lateral recum-
bency as the left hemithorax was prepared for surgery. An
incision was made in the left hemithorax over the 11
th
rib,
approximately 30cm length of rib was removed using a gigli
wire saw (Narang Medical Limited, Delhi, India) and the
space between the 10
th
and the 12
th
rib was expanded using
a Finochietto rib spreader. Te tear was located and an atel-
ectatic left lung lobe was detected. Suturing proved difcult
using this approach. A polypropylene mesh was attached to
cover the diaphragmatic defect using surgical skin staples
(Figure 4). At termination of the procedure two 32 French
drains (Well Lead Medical, Panyu district, Guangzhou city,
China) were inserted, one dorsally at the 13
th
intercostals
space and one ventrally at the 8
th
intercostal space.
Postoperatively the mare received intensive treatment
including: intravenous fuid therapy consisting of crystal-
loids (LRS) and colloids (Hetastarch, Fresenius Kabi AG,
Badhomburg, Germany)), fresh frozen plasma, antibiotic
therapy (penicillin 22.000 IU/kg q.i.d. IV and gentamicin
6.6 mg/kg s.i.d. IV), analgesics (funixin 1 mg/kg b.i.d.
IV) and anti-endotoxin therapy (polymyxin B 6000 IU/kg
b.i.d., IV, X-GEN Pharmaceuticals Inc, Northport, NY).
Ice therapy applied on all four extremities to prevent for
laminitis. Initially the horse received a nasal oxygen supply
(15 liters/min).
Post-operative radiographs confrmed good lung infa-
tion and verifed that the mesh was intact at its location.
Te drains were removed the day after surgery following a
signifcant decrease in the amount of blood and air that was
drained. Two days after surgery signifcant edema developed
at both incisions but both remained dry. At that stage, oral
antimicrobials (enrofoxacin (7.5 mg/kg s.i.d., Phibro Animal
Health Corporation, Petah Tikva, Isreal) and metronidazole
(25 mg/kg t.i.d., Vetmarket, Shoham, Israel)) and gastric
mucosal protectants (omeprazole 4 mg/kg s.i.d., Nature Vet
Pty Ltd., Glenorie, NSW, Australia) and ranitidine 6.6 mg/
kg q.i.d.) were added. Te mare recovered smoothly and was
discharged 12 days after surgery. Te mare resumed her career
as an endurance horse, with no further respiratory or colic
problems in a fve-year post-operative follow-up.
CASE 4
Clinical History
A 17-year-old male Quarter horse was referred to the
KVSM-VTH with clinical signs of acute colic, which lasted
for 12 hours. He was unresponsive to analgesics or seda-
tives and was referred to the hospital. Te owners reported
weight loss and occasional breathing difculties in the last
few months.
Te horse presented to the hospital with a heart rate of
40 beats/minute, a respiratory rate of 30 breaths/minute with
the presence of a heart murmur. On rectal examination cecal
impaction containing hard fecal material was palpated. Te
horse was treated with mineral oil (Vetmarket, Shoaham,
Figure 4: Intra-operative photograph of case 3, depicting a
polypropylene mesh stapled to a tear in the diaphragm in an 18 year-
old mixed breed mare. Long vertical arrow points to the fnochietto
rib retractors, short vertical arrow points to the polypropylene mesh
and the oblique arrow depicts the skin staples used to attach the mesh
to the diaphragm.
Research Articles
Israel Journal of Veterinary Medicine  Vol. 70 (1)  March 2015 Efraim, G. 42
Israel) and water through the nasogastric tube and LRS
intravenously. Tough the horse received potent analgesia
several times, pain recurred and emergency celiotomy was
recommended.
Case management
Preoperative medication was administered intravenously as
follows: benzylpenicillin sodium (20,000 IU/kg), gentamicin
(6.6 mg/kg), and funixin meglumine (1.1 mg/kg). Te horse
was placed under general anesthesia, positioned in dorsal
recumbency and isofurane anesthesia was used. On explor-
atory celiotomy a 6 cm x 6 cm right ventral diaphragmatic
tear was found. Te cecum was incarcerated in the hernia
and it was adhered to the pleura in several places. During
manipulation of the cecum signifcant bleeding occurred in
the thorax. Te hernia was closed by direct suturing, and a
drain was inserted into the mid-height, right hemi-thorax at
the 12
th
inter-costal space. Following recovery the horse had
respiratory distress and thoracic radiographs revealed large
intestine in the thorax, along with an old fracture in the right
fourteen rib. Te horse was taken to surgery in an attempt to
repeat the repair of the diaphragm, however death occurred
during induction.
DISCUSSION
Diaphragmatic hernia is commonly referred to as a rare lesion
in the horse (9), however it is probably more common than
previously considered (1). In one recent study, DH made up
to 1% of all colic surgeries performed between 1998 and 2005
at a university referral hospital (1). Tis fgure is comparable
with the percentage of surgeries for ileocecal intussusception
or gastrosplenic entrapment (1.3%, 0.3%, respectively) – two
conditions that are not considered rare (10). Te incidence
of DH reported in the KVSM-VTH in this study (1.3 %) is
similar to the results mentioned above. In another retrospec-
tive study from a single center, over two cases of DH per
year were recorded (6). Tus, according to this and to our
experience, DH is quite uncommon but defnitely not rare.
Te four cases making up the current series presented
exclusively diaphragmatic ruptures or defects, none of which
had a hernia sac. Tis is in accordance with previous studies,
confrming that true DHs, containing a hernia sac, are indeed
rare (1). With regard to etiology, it is reasonable to assume
that all our cases had a traumatic origin, in two cases, the
trauma was recent and in the other two, it occurred months
prior to the acute presenting episode. In several reported
cases, there was a history of trauma months to years prior
to an acute episode of colic. It is likely that the damage to
the mare’s diaphragm occurred at the time of the trauma/
parturition, however the acute episode was probably triggered
by the sudden incarceration of viscera in the thoracic cavity.
In case 1 (the 10-day old foal) the respiratory clinical
signs were mild but evident since arrival and most likely had
existed since parturition. It is likely that during parturition,
while passing in the birth canal, the flly fractured her ribs,
which tore the diaphragm. Tis case falls into the mixed cat-
egory of congenital DH with a traumatic cause. In congenital
DH, the defect is located mainly on the left side, owing to
the incomplete fusion of the pleuroperiontal folds that is
secondary to the slower development of the left lung (1).
Acquired DH also seems to be predominantly left-sided,
probably because the liver acts as a protection on the right
side (1, 2). In contrast to the predominance of left-sided
DH in the literature (1, 2, 6), in three of the four cases that
make up our series, the lesion was located on the right side
of the diaphragm. In three of the presented cases, the DH
appeared on the ventral aspect, which is consistent with their
traumatic history combined with the evidence of ipsilateral
rib fractures. Overall, two cases in this series are presumed to
be related to parturition associated trauma (cases # 1 and #3),
while two were likely due to direct external thoracic trauma
(cases # 2 and #4).
Te diagnosis of DH is typically difcult to make even
during pre-operative evaluation. Te clinical manifestations
of DH typically include acute abdominal signs or colic; colic
and dyspneic signs may be consecutive (11) or simultaneous,
and only seldom do respiratory signs occur alone. Our frst
case presented with exclusive respiratory signs for several days
prior to a fatal abdominal crisis episode. Te respiratory signs
can be attributed to the defect in the diaphragm leading to
a loss of negative pressure in the thoracic cavity resulting in
atelectatic lungs. Tis may be supported by a report describ-
ing a mare sufering from a diaphragmatic rent without any
herniation and showing respiratory signs only (12). Te fatal
episode could be attributed to the migration of viscera into
the thoracic cavity. It is interesting that case 4 had history of
respiratory problems, demonstrated as episodes of dyspnea,
months prior to the abdominal crises that led to the refer-
ral. Cases #2, #3 in our series did show signs of abdominal
Research Articles
Israel Journal of Veterinary Medicine  Vol. 70 (1)  March 2015 43 Diaphragmatic Hernia in Horses
pain, involving respiratory distress as well, however, at least
initially, respiratory distress was interpreted as part of the
abdominal crisis. Tis is consistent with the reported concern
that respiratory signs in foals with DH, are often masked by
the acute abdominal crises and attributed to abdominal pain
and stress (11).
Most commonly, DH is diagnosed either at abdominal
exploration or at necropsy. Radiographs and ultrasonography
are considered the most useful diagnostic aids for attaining
ante-mortem or pre-operative diagnosis of DH (1). In the
current series, ultrasonographic evaluation was useful though
not defnitive in the diagnosis of DH in one horse; in two
cases DH was diagnosed by abdominal exploration, and in
one case only at necropsy. Ultrasonographic evaluation can
nevertheless easily lead to false positive diagnosis due to
the bell-shaped diaphragm and the cranial migration of the
small intestine. In our experience, when used judiciously, both
ultrasound and radiograph can be helpful in the diagnosis of
DH. An efort should be made to incorporate these modali-
ties in the workup of any colic case where clinical signs are
indicative of respiratory compromise, or where the history
or initial evaluation may lead the clinician to suspect DH
(1, 12). In case #1 in this series clinical signs were exclusively
of a respiratory nature, radiographs however revealed no DH.
Te difculty in sometimes detecting DH should be borne
in mind and one should not rely on any single negative di-
agnostic test to rule out diagnosis of DH.
Te only defnitive treatment for DH is surgical repair.
Te prognosis in general is not good and it largely depends
on early diagnosis, on the location and length of the tear,
and on the degree of intestinal damage (2, 6, 8). Romero and
Rodgerson (2) reported that out of 25 horses which were op-
erated on, only 6 survived more than three months following
surgery, while 11 were euthanized during surgery. Similarly, 7
out of 44 survived to discharge in a recent retrospective study
by Hart and Brown (6). Nevertheless, long term results were
positive in the same study with 71 % of horses discharged
surviving for over a year. Recently a DH diagnosed during
abdominal exploration was successfully repaired, three weeks
later, in the standing horse, using thoracoscopy (13).
Although the thoracic approach to DH repair is described
in the literature, the conventional approach is typically ab-
dominal. Hart and Brown (6) described repairing nine DHs
via an abdominal incision, and Romero and Rodgerson (2)
reported repairing DH in 14 horses using the same approach.
In that study, fve of the horses that underwent surgery had
DH corrected by means of a polypropylene mesh applied by
direct suturing or using a hand stapling device. Four of these
horses did not survive to discharge. Tis may indicate low
chances of success in correcting DH using a mesh through
an abdominal approach. Case #4 in our series was treated by
direct suturing through the abdomen and failed immediately
after surgery. Tis defect was neither large nor dorsal but still
failed. It may further support the inferiority of the abdominal
approach for repairing DH.
Te thoracoscopy technique used by Röcken et al. (13)
agrees with our elected thoracic approach, although the
techniques used and the type of lesion was diferent. In that
report, an endoscope was used, while in case #3; in the cur-
rent report; an open approach was used performed by rib
resection. Furthermore, in that study the defect was corrected
using interrupted sutures; conversely, in our case the defect
was corrected with mesh and staples. All the above supports
our clinical impression that approaching the DH through the
thorax is preferable. Toracoscopy may prove the method of
choice for repairing DH in the future since it provides the
best access to the lesion and is minimally invasive.
By and large the surgical success rate for equine DH
repair remains low. In Romero and Rodgerson’s report
(2), 25 horses with DH underwent surgery, but only eight
survived to discharge. Similar results were reported by Hart
and Brown (6), in a population of 26 horses that underwent
surgery, seven were discharged from hospital, and two of
them died within the frst year. Te same study showed that
horses with dorsally located rents, which were 10 cm or more
in diameter, had the worst prognosis with 92% of them being
euthanized; while rents located ventrally and less than 10
cm in diameter were associated with a far better success rate
(63%). In the current study, however the only survivor had
a large and dorsal tear. No conclusions, with regards to the
efect of lesion location and size on prognosis, can be drawn
from this single case. Nevertheless, thoracic approach may
enable repair of tears that are irreparable by the traditional
abdominal approach and thus improve the overall survival
rate.
In this study, 25% of the horses with DH survived, which
is a similar survival rate to other reports (2). Two cases were
related to parturition, one in the dam and the other in the neo-
nate emphasizing that Mares and foals should be monitored
for clinical signs related to DH. Te thoracic approach proved
Research Articles
Israel Journal of Veterinary Medicine  Vol. 70 (1)  March 2015 Efraim, G. 44
useful in the current report as well as in a recent study. In
conclusion, earlier diagnosis and improved surgical techniques
may improve the survival rate of horses sufering from DH.
ACKNOWLEDGEMENTS
Te authors are grateful to the referring veterinarians and the
dedicated hospital staf without whom these difcult cases could
not have been managed.
REFERENCES
1. Kelmer, G., Kramer, J. and Wilson, D. A.: Diaphragmatic hernia:
etiology, clinical presentation, and diagnosis. Compend. Equine.
3:28-36, 2008.
2. Romero, A. E. and Rodgerson, D. H.: Diaphragmatic herniation
in the horse: 31 cases from 2001-2006. Can. Vet. J. 51:1247-1250,
2010.
3. Barker, I. K.: Te peritoeneum and retroperitoenum. In: Jubb, K.
V. F, Kennedy, P. C. and Palmar, N. (Eds.): Pathophysiology of
domestic animals. 4th ed. Academic Press, San Diego, pp. 425-
428, 1993.
4. Pauwels, F. F., Hawkins, J. F., McHarg, M.A., Rothenbuhler, R.
D., Baird, D. K. and Moulton, J. S.: Congenital retrosternal (Mor-
gagni) diaphragmatic hernias in three horses. J. Am. Vet. Med.
Assoc. 231:427-432, 2007
5. Schambourg, M. A., Laverty, S., Mullim, S., Fogarty, U.M. and
Halley, J.: Toracic trauma in foals: post mortem fndings. Equine
Vet. J. 35:78-81, 2003.
6. Hart, S. K. and Brown, J. A.: Diaphragmatic hernia in horses: 44
cases (1986-2006). J. Vet. Emerg. Crit. Care. 19:357-362, 2009.
7. Speirs, V. C. and Reynolds., W. T.: Successful repair of a diaphrag-
matic hernia in a foal. Equine Vet. J. 8:170-172, 1976.
8. Kelmer, G., Kramer, J. and Wilson, D. A.: Diaphragmatic hernia:
treatment, complications, and prognosis. Compend. Equine 3:37-
46, 2008.
9. Collier D.S.: Comparative aspects of diaphragmatic hernia. Equine
Vet. Edu. 31:358-359, 1999.
10. Mair T.S., Smith L.J.: Survival and complication rates in 300
horses undergoing surgical treatment of colic. Part 1: Short-term
survival following a single laparotomy. Equine Vet. J. 37:296-302,
2005.
11. Tapio, H., Hewetson, M. and Sihvo, H. K.: An unusual cause of
colic in a neonatal foal. Equine Vet. Edu. 24:334-339, 2012.
12. Goehring, L. S., Goodrich, L. R.and Murray, M.J.: Tachypnoea
associated with a diaphragmatic tear in a horse. Equine Vet. J.
31:443-445, 1999.
13. Röcken, M., Mosel, G., Barske, K. and Witte, T. S.: Toracoscopic
diaphragmatic hernia repair in a warmblood mare. Vet. Surg.
42:591-594, 2013.
Research Articles

Published under a Creative Commons License By attribution, non-commercial