feline-peritoneopericardial diaphramatic hernia in cats

8/14/2019 FELINE-Peritoneopericardial Diaphramatic Hernia in Cats

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Vol.18, No. 5 May 1996 Spring Feline Focus

PeritoneopericardialDiaphragmatic Herniain CatsUniversity of BernBern, Switzerland

Reto Neiger, DrMedVet

Peritoneopericardial diaphragmatic hernia is a congenital defect that per-mits communication between the pericardial and abdominal cavities.The condition is attributed to an abnormality in embryogenesis of theventral portion of the diaphragm. Several theories on the embryogenesis havebeen described in detail.1

In humans, peritoneopericardial diaphragmatic hernia can result from trau-

ma because the diaphragm forms part of the pericardium.2

In cats, however,trauma can never cause such a hernia because the pericardium is not in directcontact with the diaphragm.3 Trauma may, however, worsen an existing herniain a cat.

Pleuroperitoneal diaphragmatic hernia is the most common congenital heartdefect diagnosed in cats 2 years of age and older. 4 Berry and coworkers dis-cussed the differential diagnosis of this condition and gave the signalment of10 affected cats.5Wallace and coworkers explained the best surgical techniquefor correcting the condition in cats and gave some information on another 10cats.6

Pleuroperitoneal diaphragmatic hernia is often an incidental finding from aroutine thoracic radiograph. The most common clinical signs are respiratory

(e.g., dyspnea). Gastrointestinal signs (e.g., vomiting or diarrhea) are also com-mon. This article reviews published clinical and pathologic data on cats withpleuroperitoneal diaphragmatic hernia and reports two more cases.

CASE REPORTSCase 1Diagnosis

A 10-year-old castrated male Persian cat was presented with a 2-week historyof intermittent fever, anorexia, and lethargy. On physical examination, the cat

was quiet but alert, weighed 5.2 kilograms, and had a rectal temperature of40.6C. There was moderate tachypnea (68 breaths/min) and normal lungsounds. Heart auscultation was unremarkable, and femoral pulses of 212 beats

Continuing Education Article

FOCAL POINT

KEY FACTS

s Peritoneopericardial hernia is the

most common congenital heart

defect found in cats 2 years of

age and older.

s The hernia is often an incidental

finding in routine thoracic

radiography.

s The most common clinical signs

are nonspecific and relate to the

respiratory system (dyspnea) and

the gastrointestinal system

(vomiting or diarrhea).

s The liver is the organ that

herniates most often into thepericardium, followed by the

gallbladder and small intestine.

5Surgical correction ofperitoneopericardial

diaphragmatic hernia is

recommended for all catsexcept those that are old and

asymptomatic; the procedure

often leads to long-term survival.


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per minute were easily palpable.No other physical abnormalities

were detected.Complete blood count, bio-

chemistry panel, and urinalysis

were performed. The only abnor-mality was hyperglobulinemia(54.7 g/L; reference range, 31 to35 g/L). Tests for feline leukemiavirus and feline immunodeficien-cy virus were negative.

Thoracic radiographs (Figure 1)showed a soft-tissue mass (1.5 cmin diameter) in the caudoventralportion of the thorax overlyingthe cupula of the diaphragm. Theheart was normal in size and

shape.Ultrasonography of the thoraxshowed that this mass was in directcontact with the diaphragm andthe pericardium. Its echogenicityresembled that of the liver (Figure2). No abnormalities within thepericardium were noted.

Ultrasonography of the ab-domen showed another irregularmass (1 cm in diameter) caudal tothe stomach and near the portal

vein. All other organs were nor-mal in size, shape, position, andechogenicity. A fine-needle aspi-rate of the abdominal mass re-vealed a mixed population of lym-phocytes and lymphoblasts withfew neutrophils and macrophages.This finding, together with thehyperglobulinemia, probably re-flected a nonspecific inflammato-ry process.

Treatment After premedication with di-azepam (0.2 mg/kg intravenous-ly), anesthesia was induced withketamine hydrochloride (3 mg/kgintravenously). The cat was intu-bated with a cuffed endotrachealtube to enable the anesthetist tocontrol ventilation and to permitpositive-pressure ventilation.

Anesthesia was maintained withhalothane in oxygen.

Small Animal The Compendium May 1996

R A D I O G R A P H Y s U L T R A S O N O G R A P H Y

Figure 1Thoracic radiograph from case 1. A mass in the caudoventral portion of thethorax (about 1.5 cm in diameter) is in direct contact with the diaphragm.

Figure 2Ultrasonography of thoracic mass from case 1. The transducer was heldmedially and directly caudal to the sternum. The mass is 1.6 centimeters in diameterand has sharp margins. The echogenicity is not completely homogenous. The normalcontour of the diaphragm is interrupted.


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Exploratory laparotomy revealed a herniated liverlobe (1.5 cm in diameter) beyond a pericardioperi-toneal communication (Figure 3). The liver lobe wasnot strangulated but had adhesions to the tendinouspart of the diaphragm. After the liver lobe was reposi-

tioned and biopsy samples were collected from thelobe, the diaphragm was closed in a single layer with 2-0 polydioxanone in a continuous suture pattern. Biopsysamples were collected from the abdominal mass,

which seemed to be a lymph node.

ResultsThe cat recovered un-

eventfully. The findingsfrom the biopsy of the ab-dominal mass were consis-tent with a reactive lymph

node. The liver biopsy re-sults were considered nor-mal. According to the own-er, the cat was doing well 1year after the operation.

Case 2Diagnosis

A 5-month-old male Per-sian cat was presented witha history of weight loss,vomiting, and dyspnea. The

cat was thin, mildly lethar-gic, and had moderate con-junctivitis. Respiration ratewas 80 breaths per minute,and lung sounds were nor-mal. All other vital signs

were within normal limits.Hematologic abnormali-

ties included leukocytosis(19,300 cells/l) with mildeosinophilia (1,810 cells/l)and lymphocytosis (8,600

cells/l). A test for felineleukemia virus was negative.The serum chemistry pro-file was within normal lim-its for a cat of that age.

Thoracic radiographsdemonstrated a large car-diac silhouette (Figure 4)

with the trachea displaceddorsally. The ventral part ofthe diaphragm was notclearly visible. In place of

the liver, structures that resembled intestines were adja-cent to the diaphragm.

Ultrasonography showed that parts of the liver pro-truded through the diaphragm into the pericardium. Italso showed pericardial effusion. The diagnosis was peri-

toneopericardial diaphragmatic hernia.

Treatment Anesthesia was induced with thiobarbiturate (12

mg/kg intravenously) after premedication with di-azepam (0.2 mg/kg intravenously). After endotrachealintubation with a cuffed tube, anesthesia was main-

tained with halothane inoxygen. Surgical explorationvia a cranial midline abdom-inal incision revealed twoliver lobes within the peri-

cardium. The herniated liverhad adhesions with thetendinous part of the di-aphragm. The rest of the liv-er had no adhesions. Theliver lobes were replaced intothe abdominal cavity, andthe defect was repaired asdescribed in case 1. The catdied 3 years later after beinghit by a car.

The Compendium May 1996 Small Animal

C A R D I A C S I L H O U E T T E s A D H E S I O N S O F H E R N I A T E D L I V E R

Figure 4Lateral thoracic radiograph from case 2. The cardiac shadow is severely increasedand fills approximately two thirds of the thoracic cavity. The trachea is elevated and lies ad-

jacent to the vertebral column. The contour of the diaphragm cannot be visualized in theventral part, and gastrointestinal structures instead of liver lie caudal to the diaphragm.

Figure 3View through the ventral part of the diaphragminto the pericardial sac. The herniated liver lobe has al-ready been repositioned.


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TABLE ISignalment and Clinical Findings for Cats with Peritoneopericardial Diaphragmatic Hernia

Breed Sex Age Clinical Physical Diagnostic Herniated Other Reference Signs Findings Procedures Structures Problems

Male 1 year Neurologic signs Necropsya Small and large 7intestine, left liverlobe, gallbladder

6 months Exercise Necropsya Several liver 8intolerance lobes, gallbladder

Necropsya Parts of the liver, 9gallbladder,omentum

Domestic Female Adult None Necropsya Three liver lobes, 3shorthair gallbladder,

omentum

Persian Female 4 months Dyspnea Tachypnea, Thoracic Omentum, small 10muffled heart radiographya, surgery intestines

sounds

Domestic Male 8 months Sneezing Pyrexia, muffled Thoracic Left and right 11shorthair heart sounds, radiography,a middle liver lobes

increased lung necropsy sounds

Siamese Female 5 months Abdominal Ascites, muffled Necropsy a Right liver lobe 12cross enlargement heart sounds

Domestic Female 6 days None Necropsya Four liver lobes 13shorthair

Domestic Castrated 8 years Anorexia, Tachypnea, Thoracic Three liver lobes, Myelolipoma 14shorthair male dyspnea muffled heart radiography,a gallbladder of the liver

sounds surgery

Himalayan 4 months Dyspnea, Necropsya Left medial liver Feline infectious 15anorexia, ascites lobe peritonitis

Domestic Spayed 7 years Polyuria, Tachypnea, weak Thoracic Small intestine, 16shorthair female polydipsia, pulse, muffled radiography,a left liver lobe,

vomiting heart sounds gastrointestinal omentumstudy, surgery

Domestic Female 8 years Weight loss, Cachexia, Thoracic Parts of liver, Polycystic kidneys, 17shorthair anorexia muffled heart radiography, gallbladder anemia

sounds, large fluoroscopy of thekidneys thorax, surgery,a

necropsy

Siamese Male 2 years Weight loss, Cachexia Thoracic Parts of small Incomplete 18vomiting radiography,a surgery intestines, one sternum

liver lobe



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TABLE I (continued)Signalment and Clinical Findings for Cats with Peritoneopericardial Diaphragmatic Hernia

Breed Sex Age Clinical Physical Diagnostic Herniated Other Reference Signs Findings Procedures Structures Problems

Domestic Female 10 years Vaginal Gastrointestinal Pylorus, spleen, Tooth abscess 1

shorthair discharge study a right liver lobe,

gallbladder

Persian Female 10 years Vomiting Gastrointestinal Small intestine, 1

studya part of liver

Domestic Female 2 months Dyspnea Thoracic 1

shorthair radiography a

Persian Spayed 8 years Seizures Thoracic Fused first and 1

female radiography a second sternebrae

Female 5 months Dyspnea Necropsya Liver, gallbladder 19

Persian Castrated 2 years Vomiting, Normal Thoracic Two liver lobes Intussusception, 20

male anorexia radiography, trichobezoar

gastrointestinal

study,a surgery

Domestic Castrated 8 months Lethargy, weight Pyrexia, Thoracic One liver lobe Thrombocytopenia, 21

shorthair male loss, anorexia tachypnea, radiography, proteinuria

diarrhea tachycardia, gastrointestinal

cachexia study, angiography,a

surgery

Domestic 2.5 years Dyspnea Crepitation over Thoracic Several liver lobes Increased liver 22

longhair last ribs radiography, enzymes

gastrointestinal

study, surgerya

Persian Male 8 weeks Dyspnea, Increased lung Thoracic Small intestine, 23

exercise sounds radiography, large part of liver

intolerance gastrointestinal

study, electrocardiography,

angiography,a necropsy

Domestic Spayed 14 years Dyspnea Thoracic Several liver Myelolipoma of 24

shorthair female radiography, lobes, part of liver

necropsya omentum, gallbladder

Female 4 months Seizures, Muffled heart Thoracic Several liver 25

dyspnea, exercise sounds radiography a lobes, small

intolerance intestine

Persian Female 5 years None Heart murmur Thoracic All right 26

radiography, surgerya liver lobes



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Other CasesDiagnosisTable I summarizes the reports of 32 other feline cases

of peritoneopericardial diaphragmatic hernia publishedin 28 publications.1,3,732 It includes signalment data formost of the cases.5,6 The cats ages ranged from 6 days to14 years (mean 3.7 years). In six reports, the breed wasnot mentioned. Table II summarizes breed data from re-ported cases, including the cases described in Table Iplus 20 more cases.5,6 Thirty of 52 affected cats were re-ported to be female, 18 were reported to be male. Thesex was not mentioned in the descriptions of the other

cases. Table III shows the frequency of various clinicalsigns and physical abnormalities in cats with diagnosedperitoneopericardial diaphragmatic hernia.

The hernia was diagnosed during necropsy in ninecases. Thoracic radiography was diagnostic for ninecats. Further diagnostic procedures (e.g., upper gas-trointestinal study in three cases, angiography in threecases, ultrasonography in two cases, and positive-con-trast peritoneography in one case) were necessary forothers. Echocardiography was done to confirm the her-nia in all 10 of the cats described by Wallace andcoworkers.6

D I A G N O S T I C P R O C E D U R E S s R E S U L T S O F S U R G E R Y

TABLE I (continued)Signalment and Clinical Findings for Cats with Peritoneopericardial Diaphragmatic Hernia

Clinical Physical Diagnostic Herniated Other Breed Sex Age Signs Findings Procedures Structures Problems Reference

HimalayanSpayed 9 years Ultrasonographya 26

female

Spayed 4 years Exercise Muffled heart Thoracic Liver, 27

female intolerance sounds radiography, falciform fat

angiographya

Persian Castrated 7 years Cyanosis Muffled heart Thoracic Liver, falciform Sternal deformity 28

male sounds, cranial radiography, fat

apex beat ultrasonographya

Domestic Castrated 4.5 years Lethargy, Increased lung Thoracic Right middle liver Myelolipoma of 29

longhair male anorexia, sounds, cranial radiography, lobe, part of the livervomiting apex beat electrocardiography, gallbladder

angiography,ultrasonography,

surgerya

Persian Male 7 months Vomiting, Normal Thoracic Left middle liver 30diarrhea radiography, lobe

ultrasonography,a

surgery

Persian Female 8 months Anorexia, Pyrexia, tachypnea, Thoracic Several liver Thrombocytopenia, 31lethargy, muffled heart radiography, lobes, gallbladder anemia,

dyspnea sounds, increased peritoneography,a

lymphopenialung sounds ultrasonography,

necropsy

Domestic Male 2 years Dyspnea Tachypnea, Thoracic Right middle liver Portosystemic 32shorthair muffled heart radiography, lobe shunt

sounds, heart electrocardiography,murmur ultrasonography,a

surgery

aThis procedure confirmed the diagnosis of peritoneopericardial diaphragmatic hernia in this case.



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Exploratory laparotomy, themost invasive procedure, wasnecessary to confirm the diag-nosis for five cats. Table I dis-cusses which structures were

herniated in 32 affected cats.Concurrent congenital defectswere sternal anomaly (7 cas-es), ventral hernia (2 cases),prognathism (1 case), polycys-tic kidneys (1 case), and por-tosystemic shunt (1 case).

TreatmentThoracotomy was per-

formed on two of the catsdescribed in Table I, and la-

parotomy was performed on14 of these cats as well as onall 10 cats discussed by Wallace and coworkers. 6 Ofthese animals, 22 survived, 2 died shortly after surgery,and 1 was euthanatized during surgery because of con-comitant polycystic kidneys. One cat died 9 monthslater, possibly as a result of the hernia because reductioncould not be performed owing to severe adhesions.

DISCUSSION Although peritoneopericardial diaphragmatic hernia

is probably the most common congenital diaphragmat-

ic defect in cats, there is no report of a large series ofcats with this anomaly. Berry and coworkers gave thesignalment of 10 cats with this hernia but no furtherdetails.5 Wallace and coworkers described the surgicaltechnique used to correct the hernia in 10 cats and thepostsurgical evaluation.6

The first reported case of a peritoneopericardial di-aphragmatic hernia in a dog was described in 1811 by

J.-B. Gohier.8 The first human case was reported in190333 and the first feline case in 1909.7

Embryonic Development

Embryonic development of the body cavities is com-plex and only partially understood. By the fourth weekof development, a pericardial cavity can already beidentified in a human embryo. The embryo has a walllined with mesothelium that will become the peri-toneum.34 With the formation of the head fold, theheart and pericardial cavity are carried ventrally andcaudally.35 The pericardial cavity then opens dorsallyinto the pericardioperitoneal canals. Each pericar-dioperitoneal canal lies lateral to the foregut (the futureesophagus) and dorsal to the transverse septum (the fu-ture diaphragm)34 (Figure 5).

The lung buds then growinto the pericardioperitonealcanal, thus forming the pleu-ral cavity. As the lungs grow,a pleuropericardial mem-

brane forms cranially andeventually separates the peri-cardial cavity from the pleu-ral cavities (Figure 6). At thesame time, a pleuroperitonealmembrane forms caudallyand gradually separates thepleural cavities from the peri-toneal cavity34 (Figure 7).The diaphragm developsfrom four structures: thetransverse septum, which will

form the central tendon; thepleuroperitoneal membrane;the dorsal mesentery of the esophagus, which will formthe crura of the diaphragm; and parts of the body wall36

(Figure 8).

Congenital HerniasSeveral congenital diaphragmatic hernias have been

recognized in humans. Hiatal hernias and posterolateraldefects (through the hiatus pleuroperitonealis [foramenof Bochdalek]) account for 85% of these anomalies inhumans.2 True defects of the diaphragm and the peri-

cardium are very rare.

33,37

Only 28 cases have been re-ported: 10 attributed to a congenital defect and 18 sec-ondary to trauma.38 In humans, the diaphragm formspart of the pericardium, so there is a chance of a trau-matic peritoneopericardial diaphragmatic hernia. Incats, however, the pericardial cavity is not in contact

with the diaphragm. Traumatic injury to this part ofthe diaphragm would result in a pleuroperitoneal her-nia.3A traumatic event, however, may cause abdominalcontents to slide through an existing peritoneopericar-dial diaphragmatic hernia into the pericardial cavityand initiate acute clinical signs.22

PathogenesisSeveral theories on the embryonic development of

peritoneopericardial diaphragmatic hernia have beensuggested. The lateral pleuroperitoneal membranes andthe ventromedial pars sternalis might fail to unite dur-ing the embryonic development of the abdominal andthoracic cavities.39 The hernia might result from prena-tal injury to the transverse septum or to the site wherethe transverse septum fuses with the pleuroperitonealmembranes.40 Faulty development of the dorsolateralpart of the transverse septum or rupture of a thin tissue

P E R I C A R D I A L C A V I T Y s T R A N S V E R S E S E P T U M s T R A U M A

TABLE II

Breed Data from Reported Feline Cases ofPeritoneopericardial Diaphragmatic Hernia

Breed Number of Cats

Domestic shorthair 17Persian 12Domestic longhair 7Himalayan 4Himalayan crossbreed 1Siamese 1Siamese crossbreed 1

Angora 1Maine coon 1Russian blue 1Not specified 6

Total 52



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membrane in this area might result in a peritoneoperi-cardial communication.41,42

Because the transverse septum develops unpaired, the

latest hypothesis is that the defect results from traumat-ic rupture5 or toxin exposure in embryonic life as theliver bud undergoes rapid expansion.32 Diaphragmatichernia can be produced in rats by deprivation of dietaryvitamin A.43 The various congenital diaphragmatic ab-normalities in humans each have a separate proposedembryogenesis34; the same might be true for cats.

HeritabilityPeritoneopericardial diaphragmatic hernia has been

found in more than one dog from the same litter. Weimaraners are suggested to be predisposed. Never-

theless, no conclusive evidence exists that this le-sion is hereditary.44 In cats, congenital diaphrag-matic hernias have been attributed to an autoso-mal recessive gene; the incidence of the conditionis between 1:500 and 1:1500 births.45

Signalment of Affected CatsForty-two percent of feline cases of perito-

neopericardial diaphragmatic hernia are reported-ly diagnosed before the cat is 1 year of age, butthe condition has been discovered in animals asold as 14 years. The mean age of cats at diagnosisis 3.7 years.

Among humans with peritoneopericardial di-aphragmatic hernia, males predominate 6:1.38

Among feline cases in which the sex of the cat isknown, however, 30 of the cats were female and

18 were male. Out of 52 feline case reports inwhich breed was mentioned, 12 were Persians. In-cluding my two patients, Persians account for26% of the reported cases, thus possibly reflectinga breed predisposition.

Clinical SignsClinical signs of peritoneopericardial di-

aphragmatic hernia in cats can be nonspecific(e.g., anorexia, weight loss, or lethargy). Howev-er, respiratory signs (e.g., dyspnea) are the mostcommon manifestations. Gastrointestinal signs

(e.g., vomiting or diarrhea) are also common.Signs of cardiac compromise (e.g., abdominalswelling12) are uncommon but were implicatedin an acute death.13,19 On the other hand, thehernia is often an incidental finding in the ex-amination of asymptomatic cats.6,26 Other casesremain undiagnosed for years and are discoveredat necropsy.3

The physical examination findings are oftenunremarkable. Muffled heart sounds or a displacedapex beat can arouse suspicion.29 If concurrent cardialmalformations are present, a heart murmur may be de-

tected.6,26,32

Theoretically, the abdomen might seemempty during palpation if the hernia is large and mostof the abdominal organs are displaced cranially; butthis finding in a cat has never been reported.44

Associated AnomaliesPeritoneopericardial diaphragmatic hernia may be

associated with other congenital abnormalities. Ster-nal anomalies were the most commonly associatedanomaly, followed by ventral hernia. Polycystic kid-neys occurred in one case17 and prognathism in anoth-er.6 One cat had a congenital portosystemic shunt.32A


P E R S I A N C A T S s S T E R N A L A N O M A L I E S s C O N G E N I T A L A B N O R M A L I T I E S

TABLE IIIClinical Signs and Physical Abnormalities in Reported

Feline Cases of Peritoneopericardial Diaphragmatic Hernia

Clinical Sign or Abnormality Number of Cats Affected

Clinical Sign

Dyspnea 11

Vomiting 7

Anorexia 7

Exercise intolerance 5

Lethargy 4

Weight loss 2

Diarrhea 2

Abdominal enlargement 2

Seizures 2

Sneezing 1Polyuria and polydipsia 1

Vaginal discharge 1

Cyanosis 1

No clinical signs 5

Physical Abnormality

Muffled heart sounds 15

Tachypnea 7

Pyrexia 3

Increased lung sounds 3

Heart murmur 2Cranial displacement of the apex beat 2

Pneumonia 2

Ascites 1

Tachycardia 1

Arrhythmia 1


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similar anomaly (a portoazygos shunt) oc-curred in a 5-month-old beagle with peri-toneopericardial diaphragmatic hernia.6

A littermate of a shorthair tabby kitten with peritoneopericardial diaphragmatic

hernia had hydrocephalus.

13

This finding isinterest ing because deaths of humanneonates with congenital diaphragmatichernia are commonly associated withanomalies of the central nervous system,including hydrocephalus.43 Although con-genital heart defects have occurred in dogs

with peritoneopericardial diaphragmatichernia, none of the reported cats had suchdefects.46

Most of the congenital abnormalities asso-ciated with peritoneopericardial diaphrag-

matic hernia are not inherited but due to ac-cidents of embryogenesis.47 Associatedabnormalities, however, occurred in only 1of 28 human patients.48

DiagnosisThoracic Radiography

A routine thoracic radiograph may suggestor even confirm the diagnosis of perito-neopericardial diaphragmatic hernia (see thebox). A peritoneopericardial mesothelialremnant, which represents the dorsal border

of the hernia on the lateral thoracic radio-graph, can be seen in most affected cats.22

However, the absence of evidence of thisremnant does not rule out the hernia.

ElectrocardiographyThe electrocardiogram may be normal29 or

arrhythmic32 or may show an axis deviationbecause of cardiac displacement.23 Low-volt-age electrocardiographic readings caused bythe dampening effect of effusion or herniat-ed abdominal organs have not been reported

to occur in cats.50

Other Diagnostic ProceduresOther useful diagnostic procedures include

transhepatic ultrasonography,30 fluoroscopy ofthe thorax,17 nonselective angiography,21,27

echocardiography,6,26,32 or positive-contrastperitoneography.31 Pneumoperitoneographyand positive-contrast peritoneography canyield false-negative results when herniated vis-cera seal the diaphragmatic defect.47An uppergastrointestinal study, which is convenient

P E R I T O N E O P E R I C A R D I A L M E S O T H E L I A L R E M N A N T s C A R D I A C D I S P L A C E M E N T

Figure 6Successive stages in the separation of the pleural cavities fromthe peritoneal cavity of an embryo (transverse sections cranial to the trans-verse septum) at (A)5 weeks, (B)6 weeks, (C)7 weeks, and (D)8 weeks.Growth and development of the lungs, expansion of the pleural cavities,and formation of the fibrous pericardium are also shown. (From MooreKL [ed]: The Developing Human. Philadelphia, WB Saunders Co, 1988,pp 159169. Reproduced with permission.)

Figure 5Schematic of a human embryo (approximately day 24). (A)Thelateral wall of the pericardial cavity has been removed to show the primitiveheart. (B)Transverse section showing the relationship of the pericardioperi-toneal canals to the transverse septum and the foregut. (C)Lateral view withthe heart removed. (D)The pericardioperitoneal canals arise from the dorsal

wall of the pericardial cavity and pass on each side of the foregut to join theperitoneal cavity. (From Moore KL [ed]: The Developing Human. Philadel-phia, WB Saunders Co, 1988, pp 159169. Reproduced with permission.)



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and easily performed, is diagnostic only when bowelloops are present in the pericardium,1 a finding less com-mon in cats than in dogs.44 Computed tomography, ifavailable, would be the best diagnostic procedure, as hasbeen shown in human cases of peritoneopericardial di-aphragmatic hernia.38

Detecting AdhesionsIn cats with peritoneopericardial di-

aphragmatic hernia, the herniated organsmay have adhesions with structures in thethorax. Because of the difficulty in assessingthese adhesions noninvasively, surgical cor-

rection may be inadvisable for an old catthat has no clinical signs related to the her-nia.44 Noninvasive methods that can clearlydistinguish adhesions (i.e., computed to-mography and magnetic resonance imaging)are not readily available in veterinary prac-tice. Pneumoperitoneography and positive-contrast peritoneography are of limited val-ue when herniated viscera seal the defect.Intrapericardiac adhesions are difficult to seeultrasonographically.

Diagnostic DifferentialsEven when the clinical and radiographicsigns are strongly suggestive of perito-neopericardial diaphragmatic hernia, thediagnosis should be confirmed beforesurgery. Such diagnostic differentials as

pericardial effusion, pericarditis, cardiomyopathy, fi-broelastosis, and tricuspid valve dysplasia do not re-quire surgery.49 Pericardial, mediastinal, pulmonary,pleural, and diaphragmatic masses necessitate thoraco-tomy.30 Only peritoneopericardial diaphragmatic her-nia must be corrected via laparotomy. Surgical correc-

C O M P U T E D T O M O G R A P H Y s M A G N E T I C R E S O N A N C E I M A G I N G

Figure 8The four parts of the diaphragm: transverse septum, pleuroperi-toneal membrane, dorsal mesentery of the esophagus, and body wall.(From Wallace J, Mullen HS, Lesser MB: A technique for surgical correc-tion of peritoneal pericardial diaphragmatic hernia in dogs and cats.

JAAHA28(6):503510, 1992. Reproduced with permission.)

Figure 7(A)Lateral view of a human embryo (approximately day 33). (B)The area within the rectangleinAis enlarged toshow the primitive body cavities as viewed from the left side after removal of the lateral body wall. (C)Transverse sectionthrough the embryo at the level shown in B. (From Moore KL [ed]: The Developing Human. Philadelphia, WB SaundersCo, 1993, p 164. Reproduced with permission).



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tion of peritoneopericardial diaphragmatic hernia ledto long-term survival in 22 of 25 cats.

Degree of HerniationThe degree of herniation ranges from minimal organ

displacement to major herniation of nearly all abdomi-nal organs (with severe clinical signs).7,23 The liver andgallbladder tend to herniate most frequently, followedby small intestine, fatty tissue (e.g., omentum), andspleen. The herniated organs may be able to slide backand forth through the canal.16 This phenomenon ex-plains why some patients clinical signs vary over time.

ComplicationsThree cats with peritoneopericardial diaphragmatic

hernia had a myelolipo-matous change of the

herniated liver,

14,24,29

possibly because ofchronic hepatic hypoxiacaused by entrapmentof the affected lobes

within the pericardium.Portal hypertension canalso result from an in-carcerated liver lobe.12

AnesthesiaCats undergoing sur-

gery for peritoneoperi-cardial diaphragmatichernia should be intu-bated to permit posi-tive-pressure ventilationif the pleural space isopened. Furthermore,controlled ventilationallows the anesthetist tocoordinate respiratorymovements with reduc-tion and suturing of the

hernia. Routine anes-thetic protocols can beused for premedicationand induction. Anes-thesia can be main-tained with halothaneor isoflurane in oxygen.

Surgical ApproachA ventral midline ap-

proach from the ster-num to the umbilicus is

P O R T A L H Y P E R T E N S I O N

Radiographic Signs ofPeritoneopericardial

Diaphragmatic Hernia

s Slightly to greatly

enlarged cardiac

silhouette with dorsal

displacement of the

trachea49

s Nonuniform radiopacity

of the cardiac

silhouette49

s Overlapping of the

cardiac apex and the

cupula of the

diaphragm49

s Loculated gas or fecal

densities within the

cardiac silhouette49

s A thoracic mass

between the heart

shadow and thediaphragm30

s Microhepatica26

s Cranial displacement of

gastrointestinal

viscera17,32

s Sternal deformities1,18

s Peritoneopericardial

mesothelial remnant22


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sRecognition of the disease process andcourses of treatment

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REFERENCES1. Evans SM, Biery DN: Congenital peritoneopericardial di-

aphragmatic hernia in the dog and cat: A literature reviewand 17 additional cases. Vet Radiol21:108116, 1980.

2. Shabetai R: Specific pericardial disorders, in Shabetai R (ed):The Pericardium. New York, Grune & Stratton, 1980, pp

366419.3. Reed CA: Pericardio-peritoneal herniae in mammals, withdescription of a case in the domestic cat.Anat Rec110:113119, 1951.

4. Berry CR: Recognition of congenital heart disease in theadult dog and cat, in Bonagura JD (ed): Kirkss Current Vet-erinary Therapy. XII. Small Animal Practice. Philadelphia,

WB Saunders Co, 1995, pp 833836.5. Berry CR, Koblik PD, Ticer JW: Dorsal peritoneopericar-

dial mesothelial remnant as an aid to the diagnosis of felinecongenital peritoneopericardial diaphragmatic hernia. VetRadiol31:239245, 1990.

6. Wallace J, Mullen HS, Lesser MB: A technique for surgicalcorrection of peritoneal pericardial diaphragmatic hernia indogs and cats.JAAHA28:503510, 1992.

7. Waldmann: Ein eigenthmlicher Fall von Hernia intestinalisdiaphragmatico-pericardialis bei einem Kater.Jahrb Leistun-

gen Gebiet Vet Med29:188, 1909.8. Cited in Bru P: Foie surnumraire intrapricardique en-

globant le coeur. Rev Vet75:580587, 1923.9. Briscoe G: Hernia through the central tendon of the di-

aphragm (cat).J Anat62:224226, 1928.10. Barrett RB, Kittrell JE: Congenital peritoneopericardial di-

aphragmatic hernia in a cat.J Am Vet Radiol Soc7:2125, 1966.11. Riffel DM, Hendrickson TD, Acre KE: What is your diag-

nosis?JAVMA150:10271028, 1967.12. Frye FL, Taylor DON: Pericardial and diaphragmatic de-

fects in a cat.JAVMA152:15071510, 1986.13. Jackson OF: Congenital abnormalities in kittens. Vet Rec

84:76, 1969.14. Gourley IM, Popp JA, Park RD: Myelolipomas of the liver

in a domestic cat.JAVMA158:20532057, 1971.15. Murosaku A, Arakawa K, Okamoto T, Iida E: A feline case

of pericardiac diaphragmatic hernia. J Jpn Vet Med Assoc26:119123, 1973.

16. Atkins CE: Suspect congenital peritoneopericardial diaphrag-matic hernia in an adult cat.JAVMA165:175176, 1974.

17. Rendano VT, Parker RB: Polycystic kidneys and perito-neopericardial diaphragmatic hernia in the cat: A case report.

J Small Anim Pract17:479485, 1976.18. Bolland E, Goverts JT, Osinga EC: What is your diagnosis?

Tijdschr Diergeneeskd103:10761079, 1978.19. Odentaal JSJ: Congenital diaphragmatic hernia in a cat.

Tydskr S Afr Vet Ver:80, 1981.

20. Wilkes RD: What is your diagnosis?JAVMA 178:12971298, 1981.

21. Willard MD, Aronson E: Peritoneopericardial diaphragmat-ic hernia in a cat.JAVMA178:481483, 1981.

22. Mims JP, Mathis PD: Diagnosing a peritoneopericardialhernia. Vet Med79:911914, 1984.

23. Trautvetter E, Skordzki M, Teicher G: Kongenitale perito-neoperikardiale Hernie bei einem Katzenwelpen. Kleintier-

praxis31:383386, 1986.24. Schuh JCL: Hepatic nodular myelolipomatosis (myelolipo-

mas) associated with a peritoneo-pericardial diaphragmatichernia in a cat.J Comp Pathol97:231235, 1987.

25. Wright RP, Wright R, Scott R: Surgical repair of a congenitalpericardial diaphragmatic hernia. Vet Med82:618624, 1987.

preferred for all congenital peritoneopericardial diaphrag-matic hernias because it provides access to the entire di-aphragm. This approach does make suturing more diffi-cult, however, because the diaphragm is viewed from itsconcave surface. Lateral thoracotomy is contraindicated.47

Surgical ProcedureThe incision can be extended into the thorax if the

herniated organs cannot be reduced through the abdom-inal approach. All herniated tissue is gently reduced intothe abdominal cavity, and all devitalized tissue is excised.Incarcerated liver lobes may be infiltrated with adiposetissue and may therefore need to be excised.14,24,29

After the edges of the defect are debrided without en-try into the pleural cavity, a small hernia can be closed

with a single- or double-layer continuous suture patterncommencing dorsally and proceeding ventrally.6 There is

no need to close the diaphragm and pericardium sepa-rately.6,10When tension could be a problem in large de-fects, the pericardium is incised cranial to the diaphragmand used as a flap or free graft to close the defect.47 It isunnecessary to close the pericardium afterward.

If the pleural space was opened, pneumothorax mustbe eliminated by thoracocentesis or tube thoracostomythrough the sutured diaphragm immediately after clo-sure of the hernia.47 Prophylactic antibiotics are unnec-essary unless the liver was injured or an abdominal vis-cus was perforated.

PrognosisAlthough most of the cats had a favorable outcome af-ter surgical correction, two cats died shortly after the pro-cedure. The causes of these deaths are unknown.20,21 Nev-ertheless, correction is recommended in nearly all cases,even those found incidentally. As mentioned, reductionmay be difficult in old animals, whose herniated organsmay have adhered to the heart or the pericardium.6

ACKNOWLEDGMENTSThe author thanks Simon Knig of the Institute of

Veterinary Anatomy and Lucio Palmieri of the Small

Animal Clinic of the University of Bern for preparingthe photographs. He thanks Gina Neiger-Aeschbacher,DrMedVet, of the Small Animal Clinic of the Universi-ty of Bern and Renate Vgtli-Brger, DrMedVet, ofKleintierpraxis Gundeli, Basel, for their comments.

About the AuthorDr. Neiger is affiiliated with the Small Animal Clinic, Uni-

versity of Bern, Bern, Switzerland. He is currently affiliat-

ed with the Gastroenterology Department of Inselspital

Bern, Bern, Switzerland.


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26. Harpster NK, Zook BC: The cardiovascular system, inHolzworth J (ed): Diseases of the Cat: Medicine and Surgery.Philadelphia, WB Saunders Co, 1987, pp 911913.

27. Bailey MQ: What is your diagnosis? JAVMA 192:17531754, 1988.

28. Miller MW, Biller SB: What is your diagnosis? JAVMA193:971972, 1988.

29. Hey WH, Woodsfield JA, Moon MA: Clinical, echocardio-graphic, and radiographic findings of peritoneopericardialdiaphragmatic hernia in two dogs and a cat. JAVMA195:12451248, 1989.

30. Lamb CR, Mason GD, Wallace MK: Ultrasonographic diag-nosis of peritoneopericardial diaphragmatic hernia in a Per-sian cat. Vet Rec125:186, 1989.

31. Trebel B, Popp JP: Hernia peritoneo-pericardialis diaphrag-matica (HPPD) bei einer Perserkatzeein kongenitaler De-fekt. Tierrztl Prax19:664667, 1991.

32. Lunney J: Congenital peritoneal pericardial diaphragmatic her-nia and portacaval shunt in a cat.JAAHA28:163166, 1992.

33. Cited in Wilson AK, Rumel WR, Ross OL: Peritoneoperi-cardial diaphragmatic hernia. Am J Roentgenol Radiat Ther

Nucl Med57:4249, 1947.34. Moore KL: Development of body cavities, primitive mesen-teries, and the diaphragm, in Moore KL (ed): The Develop-ing Human. Philadelphia, WB Saunders Co, 1988, pp159169.

35. Michel G: Kompendium der Embriologie der Haustiere, ed 3.Stuttgart, Gustav Fischer Verlag, 1983, pp 270274.

36. Schnorr B: Embriologie der Haustiere, ed 2. Stuttgart, Ferdi-nand Enke Verlag, 1989, pp 198202.

37. OBrien HD: Pericardio-peritoneal communication. De-scription of a rare type of diaphragmatic hernia. J Anat74:131134, 1939.

38. Larrieu AJ, Wiener I, Alexander R, Wolma FJ: Pericardiodi-

aphragmatic hernia.Am J Surg139:436440, 1980.39. Butler N, Claireaux AE: Congenital diaphragmatic hernia as

a cause of perinatal mortality. Lancet1:659663, 1962.40. Baker GJ, Williams CSF: Diaphragmatic pericardial hernia

in the dog. Vet Rec78:578583, 1966.41. Clinton JM: A case of congenital pericardio-peritoneal com-

munication in a dog.J Am Vet Radiol Soc8:5760, 1967.

42. Bolton GR, Ettinger S, Rousch JC: Congenital perito-neopericardial diaphragmatic hernia in a dog. JAVMA155:723730, 1969.

43. Finn JP, Martin CL: Diaphragmatic pericardial hernia. JSmall Anim Pract10:295300, 1969.

44. Miller MW, Sisson DD: Pericardial disorders, in Ettinger SJ,Feldman EC (eds): Textbook of Veterinary Internal Medicine.Philadelphia, WB Saunders Co, 1995, pp 10321045.

45. Saperstein G, Leipold HW: Congenital defects in domesticcats. Feline Pract:1843, 1976.

46. Bellah JR, Spencer CP, Brown DJ, Whitton DL: Congenitalcranioventral abdominal wall, caudal sternal, diaphragmatic,pericardial and intracardiac defects in cocker spaniel litter-mates.JAVMA194:17411746, 1989.

47. Johnson KA: Diaphragmatic, pericardial, and hiatal hernia,

in Slatter D (ed): Textbook of Small Animal Surgery. Philadel-phia, WB Saunders Co, 1993, pp 455470.

48. Symbas PN, Ware RE: A syndrome of defects of the thora-coabdominal wall, diaphragm, pericardium, and heart. JThorac Cardiovasc Surg65:914919, 1973.

49. Suter PF: Peritoneopericardial diaphragmatic hernia, inSuter PF (ed): Thoracic Radiography. A Text Atlas of ThoracicDiseases of the Dog and Cat.Wettswil, Switzerland, PF Suter,1984, pp 194195.

50. Reed JR: Pericardial diseases, in Fox PE (ed): Canineand Feline Cardiology. New York, Churchill Living-stone, 1988, pp 495518.


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