Hernia, Peritoneopericardial Diaphragmatic
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Description
Pericardio-Peritoneo-Diaphragmatic Hernia (PPDH) is a congenital abnormality characterised by incomplete formation of the embryological transverse septum, meaning that the peritoneal and pericardial cavities remain continuous. Since the diaphragm (formed by the transverse septum) does not separate the two cavities, abdominal organs are able to move into the pericardial sac. The defect may occur more commonly in the Weimaraner breed of dog and in Himalayan and Domestic Long Hair cats. It is often accompanied by other congenital defects, such as umbilical hernias, sternal malformations, cardiac septal defects and pulmonary vascular anomalies. Many animals are diagnosed as adults and show few clinical signs on presentation.
Diagnosis
Clinical Signs
- The disease is frequently asymptomatic.
- Gastro-intentinal signs may be reported, including vomiting, diarrhoea, abdominal pain, anorexia and weight loss.
- Respiratory distress may occur if abdominal contents occupy a large amount of volume of the thoracic cavity.
- Cardiac signs are unusual but cardiac tamponade (with right-sided heart failure) may develop if abdominal organs are incarcerated in the pericardial sac. The heart sounds will be muffled on auscultation and borborygmi may be apparent.
Radiography
The cardiac silhouette is enlarged and continuous with that of the diaphragm. If loops of small intestine have passed into the pericardial sac, areas of as lucency may be apparent overlying the cardiac silhouette and, if necessary, this can be confirmed by a barium contrast study. The trachea may also be displaced dorsally.
Echocardiography
Definitive diagnosis generally relies on the identification of abdominal organs within the pericardial sac.
Treatment
If the animal is showing few clinical signs or if the hernia is discovered incidentally, conservative treatment may be all that is required. In animals showing overt clinical signs, the abdominal organs can be retracted via a midline coeliotomy and the defect in the diaphragm can then be closed surgically. This procedure may trap air within the pericardium so it is important to perform pericardiocentesis or pericardectomy before closure of the abdominal incision. Even though organs may have been present in the pericardial sac for prolonged periods, it is rare for adhesions to form as these structures are in constant motion.
Prognosis
A study assessing treatment regimes used in cats showed a post-operative mortality rate of 14%, whereas progressive disease was reported in 9% of those managed conservatively. This result may largely reflect the criteria used for determining whether a cat was a surgical candidate.
References
Reimer SB, Kyles AE, Filipowicz DE, Gregory CR Long-term outcome of cats treated conservatively or surgically for peritoneopericardial diaphragmatic hernia: 66 cases (1987-2002) J Am Vet Med Assoc. 2004 Mar 1;224(5):728-32
Gorman N Canine Medicine and Therapeutics Blackwell Science Fourth Edition