Hernia Between the Pericardium and Peritoneum in Dogs

Peritoneopericardial diaphragmatic hernia is a very rare congenital condition where the abdominal contents intrude and project into the pericardial cavities. This can also occur if a traumatic event causes a tear. The pericardium consists of two layers: thin, translucent membranes protecting the heart muscle at its base, and the second layer serving as a protective sac with dense fibrous tissue. The peritoneal layer represents the translucent liquid membrane that protects.  The diaphragm serves as a muscular partition that separates the abdominal cavities from the chest region and aids in supporting respiratory function.  A hernia is when an organ abnormally protrudes into your pet’s chest cavity. This condition can begin in the prenatal period during embryonic development. The congenital condition affects dogs in early life, and can take place in a very mild form, for example when the omentum (fatty tissue covering the intestines) forms a small umbilical hernia (by protruding through the area of your dog’s belly button). However, a hernia that includes the parts of the abdominal viscera (most commonly the organs such as the liver and gallbladder) can obtrude or overlap into the upper body and pericardial cavity.  This can include organs such as the stomach, small intestines, and spleen.

Peritoneopericardial diaphragmatic hernia is a condition in canines where various organs of the peritoneum (abdominal viscera) invade the pericardium cavities by either congenital factors or because of accidental trauma.

• It occurs prenatally during the embryonic stages and evolves into complications after birth
• Abnormal septum transversum (which becomes part of the diaphragm and separates the thoracic and ventral cavities) creation leads to the imperfection of the diaphragm taking form
• Because of this deficiency of the diaphragm, pleuroperitoneal  (thin tissue membranes) protecting it are weak, allowing the herniation of the abdominal viscera to enter the pericardial cavities
• One theory stems from the condition known as situs inversus totalis, where the thoracic part of the body (including the neck and abdomen) and abdominal cavities are maneuvered into an abnormal clockwise position (on the right hand side) from a normal counter-clockwise position
• As a result of this condition, the thoracic and ventral organs are aligned asymmetrically, (a reversed mirrored image) and appear to be on the right side of the body instead of the left

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When you bring your pet to the veterinary clinic, a physical examination will take place. As the veterinarian takes the vital signs of your dog, you can explain what symptoms you have seen in your pet that have caused you concern. The veterinarian will want to know his eating habits as of late, any behavioral changes you have noticed, and how his activity level has been. Be sure to let the veterinarian know if your pet has had a recent traumatic incident that could have caused a hernia. The veterinarian may do x-rays that will show that a hernia is present. The use of barium contrast may give the best picture. He may also decide upon an ultrasound of the abdominal and chest regions if further imaging is needed. An echocardiogram will be able to determine the function and condition of the heart.

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Surgery will be necessary to correct the hernia. With the use of anesthesia and careful monitoring, the surgeon will make an incision so he can view all abdominal organs that start with the liver and end with the bladder.  This enables the surgeon to withdraw the abdominal organs from the pericardial cavity, and complete the surgery by sealing the diaphragm and suturing it closed.  If the hernia has resulted from trauma and your pet has additional injuries, these will be evaluated at this time as well.

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Your dog will have to remain hospitalized, as the tubes that are inserted to remove fluids, air, and blood need to remain in tact for a period of time. Complications during recovery, such as pneumopericardium (air in the peritoneal cavity),  may be a possibility.  Air can remain trapped in the pericardial sac post-operation and can cause cardiac tamponade whereby blood and fluid accumulates between the myocardium (muscle of the heart) and pericardium. This can be fatal; therefore, monitoring is necessary. Once the veterinarina feels that your dog is stable and ready to come home, she will discharge your dog from the clinic with a list of instructions to be carefully followed at home. Pain management is necessary after surgery, as is rest for your pet. The prognosis for this type of surgery is good.

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