Pulmonary Edema in Cats

Pulmonary edema is a condition that occurs in cats when there is an excessive buildup of fluid in the air sacs of the lungs, known as alveoli. Under normal conditions, a minute amount of fluid is retained within these air sacs and continuously drained by the lymph nodes. However, when the lymphatic system is no longer able to successfully act as a drain for this fluid, the sacs retain the fluid, and this is known as pulmonary edema. Because this is a life-threatening condition in cats, it is important that owners be aware of the symptoms and how the condition can be treated.

Causes and Risk Factors

Perhaps one of the best ways to avoid the onset of pulmonary edema is to be informed about what causes it and the risk factors that can contribute to its development. For the most part, pulmonary edema in cats tends to occur as the result of another underlying health condition, causing the retention of fluid in the lungs. Causes and risk factors include:

  • Heart disease/heartworms
  • Pneumonia
  • Anemia
  • Airway obstruction
  • Protein insufficiency

Signs and Symptoms

Because of how a fluid buildup in the lungs affects a cat's ability to breathe normally, the signs of pulmonary edema are typically very noticeable. These symptoms can also be reminiscent of other conditions, so it's important to take careful note of exactly how and when the symptoms occur. Signs and symptoms include:

  • Severe shortness of breath without exertion
  • Congestive breathing sounds, indicating fluid retention
  • Wheezing
  • Breathing with the mouth open
  • Dry, hacking cough
  • Lethargy
  • Loss of appetite
  • Inability to exercise or play

Making a Diagnosis

There are a few other conditions including heartworms, pneumonia and bronchitis that can mimic the symptoms of pulmonary edema in cats, so those conditions must be ruled out before a firm diagnosis can be made. Initially, blood will be drawn, and the cat's oxygen and carbon dioxide levels will be checked. This method of testing will help determine how much oxygen from the lungs is actually being circulated throughout the blood to other organs of the body. The blood test may also include a BNP (B-type natriuretic peptide) testing. An increased result on this test may indicate that a heart condition has attributed to the onset of pulmonary edema. The next diagnostic measure will likely be a chest x-ray, which will reveal any swelling of the lung tissues and any fluid retention. Because the x-ray can actually show fluid in the lungs, it is the most firm test for this type of diagnosis.

Treatment Options

The most important aspect of treating pulmonary edema is treating or correcting the primary cause. If heartworms are the culprit, medication may be administered to rid the cat of them, if possible. In cases of heart disease, cardiac medications may be necessary to control the heart condition. The direct treatment of pulmonary edema typically consists of diuretics to help drain the fluid, and oxygen treatments to help with breathing until the fluid is removed and the condition is successfully controlled.