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Home > Cats > Fluid in a Cat’s Lungs: How it Happens, Symptoms, & Care (Vet Answer)

Fluid in a Cat’s Lungs: How it Happens, Symptoms, & Care (Vet Answer)

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Dr. Lauren Demos

Veterinarian, DVM

The information is current and up-to-date in accordance with the latest veterinarian research.

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There are many various illnesses that can strike a cat, but fluid in or around their lungs is one of the more concerning. Cats are excellent at hiding signs of illness, so fluid in their chest is a common illness that is only diagnosed once a cat has been to see their vet.

However, there are a number of symptoms that you can watch for at home that might indicate the issue is occurring. We will explore these, as well as how the condition happens, and the care involved for your furry friend if it does. Read on to learn more.

divider-catHow Does Fluid in the Lungs Happen?

The first step to understand how fluid in the lungs happens, is to understand the anatomy of the lungs. The lungs are found within the thoracic or chest cavity, and work to introduce oxygen into the bloodstream, as well as to help balance the pH of the body. They also have key roles in being a sentinel for the immune system. The lungs are divided into a left and right side. In cats, the lungs are not fully symmetrical, with an accessory lung lobe on the right side.

Fluid can build up in two places in the chest: within the lungs themselves (edema), or around the lungs—between the lung tissue and the chest wall (effusion).

Lung or pulmonary edema can occur for a variety of reasons including pneumonia from bacteria or viruses, parasitic infections, cancer, trauma, heart failure or other cardiac disease, and electrical shock. Edema can be troublesome in that it decreases the lungs’ capacity to oxygenate the blood by decreasing the volume of working lung tissue. The functional units of the lungs are called alveoli. Once they are filled with fluid, they cannot work to exchange carbon dioxide and oxygen, and the lung function becomes impaired.

Thoracic effusions can occur from lymphatic blockages, cardiac (heart) disease, cancer, infections, and other causes. Thoracic effusions decrease the ability of the lungs to expand. This can involve one, or both sides, of the chest. When severe, lung expansion can be quite compromised, and again, difficulty in oxygenating the blood can be marked.

cat in vet clinic
Image By: Andy Gin, Shutterstock

What Are the Symptoms of Fluid in a Cat’s Lungs?

Fluid in cats’ lungs may have various different presentations, depending on how much fluid is present, how long it has been present for, how active the cat is, what the underlying cause is, and whether other health concerns exist or not.

Symptoms can include:

  • Lethargy
  • Weakness
  • Fast or heavy breathing
  • Open mouth breathing
  • Pale gums and mucus membranes
  • Exercise intolerance
  • Fast heart rates
  • Difficulty in breathing
  • Loss of appetite
  • Hiding
  • Fever

How Can You Care for a Cat with Fluid in Their Lungs?

Fluid in a cat’s lungs or chest requires a medical diagnosis to know how best to proceed. This means that your cat needs to see their vet, and often requires imaging, such as an ultrasound or x-rays, to identify what is going on with regard to the fluid. Sometimes, labwork will also be performed.

In severe cases, the treatment will involve hospitalization, and may include IV fluids, oxygen therapy, diuretics, antibiotics, and pain relievers, amongst others. Some cats may be able to go home with medications, provided they are stable enough to do so.

Caring for a cat with fluid in their lungs involves following the treatment protocol outlined by your cat’s vet. This includes adhering to the timing of their medications, minimizing stress, monitoring their eating habits along with their urinations and defecations, and overall ensuring that your cat is responding to treatment. You may also be asked to count your cat’s resting respiration rates, which in general, should fall around less than 30 breaths per minute when they are at rest or asleep, and not purring.

Travelling with your cat, allowing them outside, and introducing stressors—such as new people into the house, or moving during this time—would be less than ideal. Caring for your cat if they have fluid in their lungs best involves quiet, restful environments, appropriate food and medications, and as much attention as they desire.

vet hecking bengal cat
Image by: Pressmaster, Shutterstock

Frequently Asked Questions (FAQs)

What are the outcomes for cats with fluid in their lungs?

Cats can completely recover from fluid buildup in their lungs, depending on the underlying cause. Cats can also go for a long time before this fluid is discovered, since many live relatively sedentary lifestyles. Conversely, this means that the symptoms can, therefore, be difficult to detect as well, and cats may live for weeks or months with fluid in their lungs before it is detected.

What are some diseases that can cause fluid in a cat’s lungs?

There are a number of diseases that can cause fluid buildup in a cat’s lungs. It is also important to note that this is a different condition than fluid around a cat’s lungs, which is called pleural effusion. Fluid in the lungs, referred to as pulmonary edema, can be caused by the  following:

  • Congestive heart failure
  • Pneumonia (viral, bacterial)
  • Parasitic infections
  • Abscesses
  • Lymphatic blockages
  • Cancers
  • Trauma
  • High temperatures
  • Drowning
  • And others


Fluid in cats’ lungs, whether in the lungs themselves or in the chest cavity, is always a serious concern. Because the causes are varied, and because a definitive diagnosis is generally not possible without imaging and/or labwork, any suspicion for fluid in your cat’s lungs should involve a trip to your cat’s veterinarian. It is important, however, if your cat is severely ill, that you call ahead of time to get recommendations about how best to transport your cat—to reduce the stress of travel, and most safely get your cat into the clinic. Sometimes, a stable cat can quickly become far worse with the stress of travel when leaving home.

The best way to prevent severe illness in cats is to be highly attuned to their normal behaviors, so that, at the earliest sign of illness, you can detect these changes, and get your cat the help they need before any illness becomes too severe.

Featured Image Credit: Kachalkina Veronika, Shutterstock

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