Peritoneopericardial diaphragmatic hernia is due to faulty transverse septum development in the embryo.1-3 The transverse septum develops into the central tendon of the diaphragm. Peritoneopericardial diaphragmatic hernias have
been reported in dogs, cats, rabbits, a donkey, and a calf.4 In dogs and cats, this condition is not due to a postnatal traumatic episode because, unlike in people, the peritoneal and
pericardial cavities are not directly connected. No sex or breed predilection is reported,5 although in one study 4 of 13 dogs (31%) were Weimaraners and 9 of 34 cats (26%) were Persians.5,6 Peritoneopericardial diaphragmatic hernias are usually an incidental finding. No age predisposition is reported. These hernias
have been found in dogs as early as 14 weeks old and as late as 10 years old; they've been seen in cats as early as 8 weeks
old and as late as 14 years old.5,6 Other congenital anomalies such as hydrocephalus, umbilical hernias, sternal defects, cranial midline abdominal hernias,
abnormal swirling of hair on the ventral abdomen, intracardiac defects, and pulmonary vascular disease can be seen in conjunction
with peritoneopericardial diaphragmatic hernias.1,4-6
Peritoneopericardial diaphragmatic hernias are usually diagnosed by performing thoracic radiography, ultrasonography, and
contrast radiography. These hernias are also incidental findings at necropsy. Common clinical signs may include respiratory
signs such as dyspnea, tachypnea, coughing, or wheezing and gastrointestinal signs related to anorexia, polyphagia, vomiting,
or diarrhea. Other signs include weight loss, abdominal pain, ascites, exercise intolerance, shock, and collapse.1,5,6
Peritoneopericardial diaphragmatic hernias are rare but should be included as a differential diagnosis in a cat with an enlarged
cardiac silhouette. Surgical correction is the treatment of choice. Complications that arise are usually directly related
to the organs that are herniated, such as myelolipomatous change of the herniated liver, portal hypertension, and reperfusion
injuries.2 Also, adhesions to organs in the thoracic cavity can occur and complicate the surgery. The prognosis after surgical correction
of the defect, in the absence of other complicating factors, is good for normal life expectancy.5,6
The photographs and information for this case were provided by Joshua F. Rexing, DVM, and Bradley R. Coolman, DVM, MS, DACVS,
Veterinary Surgical Services, 5818 Maplecrest Road, Fort Wayne, IN 46835. Dr. Rexing's current address is Petsburgh, 2506
Schuyler Ave., Lafayette, IN 47905.
1. Hunt, G.B.; Johnson, K.A.: Diaphragmatic, pericardial, and hiatal hernia. Textbook of Small Animal Surgery (D. Slatter, ed.). W.B. Saunders, Philadelphia, Pa., 2003; pp 471-485.
2. Frye, F.L.; Taylor, D.N.: Pericardial and diaphragmatic defects in the cat. JAVMA 152 (10):1507-1510; 1968.
3. Mims, J.P.; Mathis, P.D.: Diagnosing a peritoneopericardial hernia. Vet. Med. 79 (7):911-914; 1984.
4. Wright, R.P. et al.: Surgical repair of a congenital pericardial diaphragmatic hernia. Vet. Med.
82 (6):618-624; 1987.
5. Evans, S.M.; Biery, D.O.N.: Congenital peritoneopericardial diaphragmatic hernia in the dog and cat: A literature review
and 17 additional case histories. Vet. Radiol. 21:108-116; 1980.
6. Neiger, R.: Peritoneopericardial diaphragmatic hernia in cats. Compend. Cont. Ed. 18:461-478; 1996.