Pericardial Disease in Cats

Overview of Feline Pericardial Disease

The pericardium is a membrane that covers the heart. It consists of two layers: a visceral layer (epicardium), tightly adhered to the heart muscle, and an outer parietal layer. Between these two membranes is a space, the pericardial space, which normally contains a small amount of fluid. The pericardium is not elastic 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.

Below is and overview of Pericardial Disease in Cats followed by in-depth information on the diagnosis and treatment of this condition.

Several illnesses can affect the pericardium. These include peritoneopericardial diaphragmatic hernia, pericardial effusion, and constrictive pericardial disease.

Peritoneopericardial Diaphragmatic Hernia

This type of hernia is present at birth and is more common in cats than dogs. Affected cats are born with an abnormality of the diaphragm that allows the abdominal contents to slip into the pericardium. In cats, the hernia often only contains fat and liver lobes. In dogs, the hernia often contains loops of intestine.

Pericardial Effusion

Pericardial effusion refers to an abnormal amount of fluid accumulating within the pericardial space. Different types of fluid, including clear fluid, pus, or blood may accumulate. As fluid accumulates, the heart’s action is restricted by building pressure in the pericardial space since the pericardial sac is unable to distend. Eventually, the heart is unable to adequately pump blood to the body and the cat collapses. Without emergency treatment, death is imminent.

Constrictive Pericardial Disease

Pericardial constriction most often develops secondary to chronic inflammation, particularly from infective processes within the pericardium, or recurrent hemorrhage. Rarely, the pericardium may accumulate calcium deposits. With chronic inflammation, the pericardial space can 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

• Weakness
• Collapse
• Difficulty breathing
• Pale gums
• Lack of appetite

Diagnosis of Pericardial Disease in Cats

Blood work is often performed to determine the overall health of the cat. Usually, the blood work is normal, but some cat may be found anemic or to have other abnormalities.

Chest radiographs (X-rays) are performed to determine the size and shape of the heart.

Ultrasound of the heart (echocardiogram) is performed both to confirm pericardial disease and to determine the type.

Treatment of Pericardial Disease in Cats

Treatment varies depending on the type of pericardial disease.

Peritoneopericardial diaphragmatic hernia is often an incidental finding and usually does not cause the cat to be ill. In such cases, the cat is simply observed for signs of illness. For cats that have clinical signs of disease associated with peritoneopericardial diaphragmatic hernia, surgery is the only treatment.

Pericardial effusion is treated by removing the fluid that has accumulated in the pericardial sac and by attempting to treat or remove the cause of the fluid accumulation.

Constrictive pericardial disease is treated by surgical removal of the pericardium.

Home Care and Prevention

There is no home care for pericardial disease. If you suspect that your pet may have pericardial disease, see 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 Cats

There are a variety of causes depending on the type of pericardial disease.

• Peritoneopericardial diaphragmatic hernia is a congenital disorder with no known cause. It is present at birth.
• Pericardial effusion occurs secondary to pericarditis i.e. inflammation of the pericardium. Fluid accumulation within the pericardium may be caused by peritoneopericardial diaphragmatic hernia, right-sided heart failure, cysts, low blood protein (albumen), or infection. Bleeding within the pericardium can be due to heart tumors, trauma, or blood clotting problems. In some cases, the cause of the pericardial effusion cannot be determined.
• Pericardial constriction most often develops secondary to chronic inflammation, particularly from infection, recurrent hemorrhage, or as a consequence of diffuse cancer.

The prognosis for pericardial disease depends on the cause. Cats with bleeding into the pericardium from an unknown cause have a fair to good prognosis. Cats with pericardial fluid accumulations caused by infection have a guarded prognosis; and cats with pericardial fluid due to a tumor of the heart have a poor prognosis.

Diagnosis In-depth

Various diagnostic tests are necessary to diagnose pericardial disease and determine the underlying cause.

• A complete blood count (CBC) is performed to evaluate the red blood cells, white blood cells, and platelets. In some cats, the red blood cell count may be low, indicating anemia. If the white blood cell count is elevated, it may indicate infection.
• Serum biochemistry profile is performed to evaluate electrolyte levels and organ function. Various abnormalities may be detected, including kidney disease or liver disease.
• Radiographs (X-rays) of the chest are performed to help determine if pericardial disease is present. When there is pericardial effusion, the heart will appear larger than normal and globoid. If a hernia is present, loops of intestine may be seen overlying the heart.
• A barium contrast X-ray may be recommended if peritoneopericardial hernia is suspected and cannot be confirmed on plain radiographs. Barium is a liquid that, when ingested, shows up readily on X-rays. If intestinal loops are present within the pericardium, barium will help confirm their presence.
• Ultrasound is the best way to diagnose pericardial disease. Ultrasound of the heart, called an echocardiogram, shows if a hernia is present or if fluid is present. With the help of ultrasound, fluid around the heart can be removed with a needle and subsequently evaluated. The heart can also be evaluated to determine if a tumor is present.

Treatment In-depth

Treatment varies on the type and severity of pericardial disease. Treatments may include the following:

• For most cases of peritoneopericardial diaphragmatic hernia, no treatment is necessary since most cat are clinically unaffected. If the cat becomes ill or has difficulty breathing, surgery is necessary to repair the hernia.
• Treatment for pericardial effusion involves removal of the fluid (pericardiocentesis) and treatment of the underlying cause. Once a significant amount of fluid is removed with a catheter or needle, additional therapy can be administered. Sometimes, repeated removal of fluid is necessary.
• Medical therapy is rarely indicated for treatment of pericardial effusions. If the cat has collapsed, or has profoundly low blood pressure, intravenous fluids may be needed for resuscitation. Furosemide or other medications supposed to reduce fluid in the pericardium have not been shown effective.
• Surgery may be necessary for successful management of pericardial diseases. Removal of the pericardial sac may be indicated where there is recurrent effusion of unknown cause. Treatment for infective pericardial disease involves catheter drainage of the pericardium, subsequent surgical removal and drainage of the pericardial space (to prevent constriction), and specific antibiotic therapy based on culture.

Surgery is also indicated if constrictive pericardial disease is diagnosed or highly suspected. If a tumor is suspected but cannot be confirmed on ultrasound, surgery may be needed to determine whether a tumor is present or to attempt to remove the tumor. In some cases in which hemorrhagic pericardial effusion is caused by a tumor, a small window may be cut into the pericardium to allow the blood to leak out of the sac and into the chest cavity, where it can be absorbed.

Follow-up Care for Cats with Pericardial Disease

After treatment, affected animals must be closely monitored for up to a year. Repeat X-rays and ultrasound are periodically necessary to monitor the cat’s response to therapy and recurrence/deterioration. Blood work should be repeated at intervals if initial results revealed abnormalities.

Animals with pericardial disease can deteriorate rapidly. Unfortunately, cats with pericardial disease caused by tumors often succumb to the disease a short time after diagnosis.