How to Recognize Fluid in a Cat’s Lungs

How to Recognize Fluid in a Cat’s Lungs

fluid in a cats lungfluid in a cats lung
fluid in a cats lungfluid in a cats lung

Cats can have various medical problems that can cause difficulty breathing. Cat owners commonly want to know how to recognize if there is fluid in a cat’s lung. The medical term for the accumulation of fluid in the lungs is pulmonary edema. Fluid in a cat’s lung can be caused by congestive heart failure, trauma, or potentially by an infection such as pneumonia. In this article, we will review signs of trouble breathing in cats and possible causes for fluid in cats lungs and other signs of trouble breathing.

Difficulty breathing, or “shortness of breath”, is commonly referred to by the medical term “dyspnea”. This can manifest in cats as an increased respiratory rate, increased respiratory effort (working harder to take breaths), open mouth breathing, and/or an abnormal posture to breath. Cats that have fluid in their lungs or have difficulty breathing may sit with their head and neck extended with the elbows back (see figure 1).

Cat dyspneaFigure 1. Cat with slight trouble breathing from fluid in lungs. This cats elbows are back and neck slightly extended. Some cats may have their next extended more as the difficulty progresses. 

Difficulty breathing can occur at any time during a cat’s breathing process, during inspiration (breathing in) or expiration (breathing out).

Figure 2. This cat is having severe trouble breathing due to fluid in lungs. This cat’s neck is slightly extended and he is very weak. He is also open mouth breathing. This cat has congestive heart failure from hypertrophic cardiomyopathy.




There are many different reasons a cat can have difficulty breathing. When a cat has trouble breathing, he may not be able to get an adequate supply of oxygen to tissues. For example, there can be airway problems from asthma, a foreign body in the airway causing an obstruction, an infection, or accumulation of fluid (edema) in the lungs, bruising of the lungs (pulmonary contusions), or an abnormal accumulation of fluid in the chest cavity (Pleural Effusion in Cats).

Why Cat’s Lungs Fill With Fluid

Fluid in a cat’s lung can be caused by several different diseases. The problems are often categorized by those caused by underlying heart problems (cardiogenic) and those not caused by a heart problem (non-cardiogenic).

Cardiogenic Causes

  • Congestive heart failure (CHF) is a condition resulting from the heart’s inability to sufficiently pump blood to adequately to meet the body’s needs. This failure leads to an increased respiratory effort caused by fluid in or around cat’s lungs. Two common heart diseases that cause congestive heart failure are Hypertrophic Cardiomyopathy in Cats and the other is Dilated Cardiomyopathy in Cats. These diseases can cause lethargy, weakness, lack of appetite, and decreased exercise capacity. Most cats won’t eat when they can’t breathe well.

Non-Cardiogenic Causes

  • Pneumonia is an infection of the lungs that usually results from a bacterial infection. The most common way a cat acquires pneumonia is by inhalation. Cats with pneumonia may suffer from a compromised immune system. Pneumonia can occur at any age but is more common in kittens or senior pets.  Learn more about Pneumonia in Cats.
  • Cancer is an uncontrolled growth of cells on or within the body. Cancer is common in cats and the risk of cancer increases with age. In fact, cancer accounts for almost half of the deaths of pets over 10 years of age. Cancer may be localized, or it may invade adjacent tissue and spread throughout the body. Cancer can develop in the lungs, spread to the lungs, or occur in tissues near the lungs that lead to fluid in the lungs or around the lungs. Intact (non-spayed) female cats are predisposed to breast cancer (metastatic mammary carcinoma).
  • Upper respiratory tract infections (URTI) are amongst the most common conditions that occur in cats and kittens.  Signs can range from sneezing, running eyes, inflamed conjunctiva, ulcers in the mouth, and/or trouble breathing. Learn more with this article –  Feline Upper Respiratory Tract Infections.
  • Head trauma can occur in cats from being hit by a car, crushed in a recliner, bites from other animals, or other kinds of trauma. Some cats with head trauma can develop lung inflammation that causes fluid in the lungs.  Learn more about Head Trauma in Cats.
  • Electrocution or electric shock results in injury to nerve cells from the intense heat generated as the electricity passes through the body tissues. The most common source of electrical injury to cats is when they bite electrical cords carrying low voltage household currents. This is most common in young playful cats and kittens. Exposure to high voltage electrical current is uncommon and is usually fatal due to massive internal damage. Learn more about electric shock in cats.
  • Seizures, also known as fits or convulsions, are a sudden excessive firing of nerves in the brain. It results in a series of involuntary contractions of the voluntary muscles, abnormal sensations, abnormal behaviors, or some combination of these events. A seizure can last from seconds to minutes in cats. Seizures are symptoms of a neurological disorder but are not a disease in themselves. Some underlying causes of seizures in cats include inflammatory brain diseases, brain tumors, symptoms from toxins, or epilepsy. Learn more about Seizures in Cats.
  • Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) are severe respiratory diseases that can occur in cats. These diseases are well characterized in human medicine but less well understood in cats.  Complex changes occur that leads to cellular inflammatory changes that cause progressive trouble breathing and sometimes fluid accumulation in the lungs. This most often occurs in cats with infections or pneumonia.

Disease Commonly Confused with Fluid in Cat’s Lungs

There are other diseases that can be confused with those that cause fluid in cat lungs.  One problem that comes is Feline Asthma.

Asthma in cats, also known as “feline allergic asthma” or “feline allergic bronchitis”, is a lung condition associated with airway obstruction caused by sudden narrowing of the bronchial tubes. These symptoms are caused by the spasmodic constriction of the bronchial tubes and increased production of secretions from the bronchial tree. Common symptoms in cats include coughing, difficulty breathing, increased respiratory effort or wheezing breathing. Some cat owners confuse the wheezing with fluid in the cat’s lungs.

How to Recognize the Problem

You can recognize fluid in cat’s lungs by evaluating your cats breathing. Trouble breathing is considered an emergency and it is best if you see your veterinarian immediately.

Signs of fluid in a cats lungs may include:

  • Increased respiratory rate (>40 breaths per minute)
  • Increased respiratory effort (working harder to take breaths)
  • Open mouth breathing
  • Abnormal posture (cats that have difficulty breathing may sit with head and neck extended with the elbows back
  • Lethargy
  • Weakness
  • Reluctance to play
  • Hiding
  • Withdrawing from family activities
  • Coughing

If you see the above signs in cats, please see your veterinarian. They may be able to determine if there is a fluid accumulation based on your cat’s clinical signs and auscultation of the lungs in conjunction with radiographs of the chest (chest x-rays).  Other tests that your vet may want to do is a blood pressure measurement, an electrocardiogram (EKG), an ultrasound examination of the heart (echocardiogram), and/or laboratory (blood) tests.

Treatment of fluid in Cats Lungs

Treatment of fluid in cats lungs will vary and depend on the underlying cause of the fluid and location of the fluid. Common treatments may include:

  • Oxygen supplementation
  • An emphasis in care to minimizing stress
  • Thoracocentesis – a procedure to drain fluid that has accumulated around the lungs (pleural effusion)
  • Drug therapy with diuretics – Commonly known as a “water-pill”, diuretics can be given orally or by injection. The most common diuretic used is furosemide (Lasix®)

Additional Articles of Interest Relating to Fluid in Cat Lungs:

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