Overview of Canine Pericardial Disease
The pericardium is a membrane that surrounds the heart. It consists of two layers: a visceral layer (epicardium) that is tightly adherent to the heart muscle and an outer parietal layer. Between these two layers is a potential space, the pericardial space, which normally contains a small amount of fluid. The pericardium is inelastic and does not distend easily. When excessive fluid accumulates within the pericardial space, the heart loses its ability to beat normally and serious illness can occur.
Illness that Affect the Canine Pericardium
Several illnesses can affect the pericardium in dogs. These include peritoneopericardial diaphragmatic hernia, pericardial effusion, and constrictive pericardial disease.
Peritoneopericardial Diaphragmatic Hernia
This type of hernia is present from birth. Affected dogs are born with an abnormality of the diaphragm, which allows abdominal contents to slip into the surrounds the pericardial space. In dogs, the hernia more often contains loops of intestine.
Pericardial effusion is a term used to describe an accumulation of fluid within the pericardial space. Different types of fluid, including clear fluid, pus, or blood, may accumulate. As fluid accumulates, the heart’s action is compromised as fluid pressure builds up on account of the inability of the pericardial sac to distend. Eventually, the heart is unable to adequately pump blood to the body and the dog may collapse. Without emergency treatment, death is imminent.
Constrictive Pericardial Disease
Pericardial constriction most often develops secondary to chronic inflammation, particularly as a result of infective disease of the pericardium, or recurrent hemorrhage. Rarely, calcium deposits thicken the pericardium. In chronic inflammation, the pericardial space may become obliterated and the heart encased in a rigid, poorly expansive sac. As the fluid is reabsorbed, the pericardium scars and contracts, and consequently the chambers of the heart become constricted and cannot expand effectively. This condition limits the heart’s ability to pump blood and can lead to right-sided heart failure.
What to Watch For
Signs of Pericardial Disease in Dogs may include:
Diagnosis of Pericardial Disease in Dogs
Blood work is often performed to determine the overall health of the animal. Usually, the blood work is normal, but some animals may be anemic or have other abnormalities.
Chest radiographs (X-rays) are performed to determine if the size and shape of the heart.
Ultrasound of the heart (echocardiogram) is performed both to confirm pericardial disease and determine the type.
Treatment of Pericardial Disease in Dogs
Treatment varies depending on the type of pericardial disease.
Peritoneopericardial diaphragmatic hernia is often an incidental finding and usually does not cause obvious illness. In such cases, the dog should be observed over time for signs of developing illness. For dogs that have clinical signs of disease associated with peritoneopericardial diaphragmatic hernia, surgery is the only treatment.
Pericardial effusion may be treated by removing fluid that has accumulated in the pericardial sac. In addition, attempts should be made to address the inciting cause of the fluid accumulation.
Constrictive pericardial disease is treated with surgical removal of the pericardium.
Home Care and Prevention
There is no home care for pericardial disease. If you suspect that your dog has pericardial disease, consult your veterinarian. Prevention of pericardial disease is difficult and often not possible. Early diagnosis and treatment can help reduce the risk of serious illness.
In-depth Information on Pericardial Disease in Dogs
There are a variety of causes of pericardial disease.
Pericardial disease can occur in dogs of any age. Weimaraners are predisposed to peritoneopericardial diaphragmatic hernias. Golden retrievers are more likely to have bleeding in the pericardium from an unknown cause. Heart tumors, primarily hemangiosarcoma, are more common in German shepherds, golden retrievers and Labrador retrievers. Another type of heart tumor, called an aortic body tumor, is especially common in older short-nosed breeds such as pugs, bulldogs or Pekingese.
The prognosis for pericardial disease depends on the cause. Dogs with bleeding into the pericardium from an unknown cause have a fair to good prognosis. Dogs with pericardial fluid accumulation caused by infection have a guarded prognosis. Dogs with pericardial fluid accumulations arising as a result of a heart tumor have a poor prognosis.