Fluid in the Lungs in Dogs

What Is Fluid in the Lungs in Dogs?

Pulmonary edema, is the abnormal buildup of fluid in the lungs. In dogs, this condition is most associated with pneumonia, but many other health complications can lead to pulmonary edema in dogs.

A small amount of fluid is necessary for normal lung function, as it facilitates the gas exchange that is needed to breathe. However, lung fluid content must be carefully balanced between the tiny air sacs (alveoli) and small blood vessels that nourish the lungs. If this balance is disrupted, too much fluid accumulates in the alveoli, resulting in pulmonary edema.

The alveoli are normally filled with air, and if the air is replaced with water, breathing becomes difficult. This can cause an affected dog to feel extreme distress. If left untreated, pulmonary edema in dogs can cause lung tissue damage.

Fortunately, when the condition is treated quickly by a veterinarian, an affected dog typically has a good prognosis. However, this can depend on the underlying cause. Fluid in the lungs in dogs is a common complication of conditions such as respiratory infection and certain heart issues.

Fluid in the lungs in dogs can accumulate slowly or quickly, and it is considered a veterinary emergency to ensure a dog’s oxygen supply isn’t compromised.

Symptoms of Fluid in the Lungs in Dogs

An affected dog’s symptoms depend on their condition’s underlying cause. However, no matter the cause, fluid in the lungs affects breathing and heart function.

Symptoms of fluid in the lungs in dogs typically include:

• Increased respiratory rate

• Open-mouth breathing

• Increased abdominal movement during breathing

• Coughing

• Wheezing

• Weakness

• Crackling noises during breathing

• Pale or blue lips, gums, or tongue

• Collapse

Causes of Fluid in the Lungs in Dogs

Fluid in the lungs in dogs can be characterized as originating either from a heart condition (cardiogenic) or from another condition (noncardiogenic). Dogs of all ages, breeds, and genders are susceptible to pulmonary edema, but some are at a higher risk for certain conditions that lead to fluid in the lungs.

Cardiogenic pulmonary edema occurs when a dog has advanced heart disease that causes left-sided congestive heart failure, in which the heart’s inability to pump effectively leads to blood accumulation in the vessels that carry blood away from the lungs.

These conditions include:

• Degenerative mitral valve disease (DMVD)—When the mitral valve, which is between the heart’s upper and lower left chambers, deteriorates, it can no longer close properly, allowing blood to flow backward.

  • Dogs at higher risk for DMVD include:

    • Cavalier King Charles Spaniels

    • Chihuahuas

    • Cocker Spaniels

    • Miniature Schnauzers

    • Pomeranians

    • Dachshunds

    • Pekingese

• Dilated cardiomyopathy (DCM)—DCM is caused by heart muscle degeneration that causes the heart wall to thin and weaken, inhibiting the heart’s ability to pump blood.

  • This is the most common cause of heart failure in large-breed dogs, including:

    • Boxers

    • Doberman Pinschers

    • Great Danes

    • Irish Wolfhounds

    • Newfoundlands

    • Saint Bernards

• Patent ductus arteriosus (PDA)—During fetal development, an opening called the ductus arteriosus is present between the two main blood vessels leading to the heart. The opening normally closes when puppies are born. PDA is a heart defect that occurs when this opening fails to close.

  • This condition is more common in female dogs, and breeds at increased risk include:

    • Maltese

    • Pomeranians

    • Cocker Spaniels

    • German Shepherds

    • Labrador Retrievers

Heart issues are not always the reason a dog accumulates fluid in their lungs. Noncardiogenic pulmonary edema can occur for several reasons, such as:

• Pneumonia

• Anemia

• Heartworm disease

• Airway obstruction

• Smoke inhalation

• Toxins

• Low blood protein levels

• Electrocution

• Altitude sickness

• Brain trauma

• Epileptic seizures

• Near drowning

• Cancer

How Veterinarians Diagnose Fluid in the Lungs in Dogs

If your dog is showing signs that could indicate pulmonary edema, they should be examined by a veterinarian. Tests your vet may perform to diagnose fluid in the lungs in dogs include:

• History—A thorough history is important, and you need to let your veterinarian know if your dog has ingested a toxic substance, was bitten by a venomous snake, was exposed to smoke or high altitude, experienced an electrical shock, or any other relevant information that could help them diagnose the condition.

• Physical exam—Your veterinarian will perform a nose-to-tail physical exam to check your dog for abnormalities. Listening with a stethoscope to your dog’s heart and lung sounds is a crucial part of this exam, as abnormal respiratory noises can help your veterinarian determine how to proceed.

• Blood work—Blood work, such as a complete blood count (CBC) and biochemistry profile, provides useful information about your dog’s overall health and can help determine if an infection is present.

• Chest X-rays—Chest X-rays are extremely helpful for diagnosing pulmonary edema. These images can show the amount of fluid in your dog’s lungs, a foreign body that may cause an airway obstruction, or heart enlargement if your dog has cardiogenic pulmonary edema.

• Electrocardiogram (EKG)—Your veterinarian may perform an EKG to assess the electrical activity of your dog’s heart.

• Heart ultrasound—If your veterinarian suspects cardiogenic pulmonary edema, they may perform a heart ultrasound, often referred to as an echocardiogram, to evaluate your dog’s heart.

• Pulmonary fluid testing—Your veterinarian may take a sample of your dog’s pulmonary fluid through aspiration or bronchoscopy to test for infection or elevated protein levels.

Treatment of Fluid in the Lungs in Dogs

Treatment for pulmonary edema in dogs depends on whether your dog’s condition is cardiogenic or noncardiogenic.

Let’s look at each possible situation:

• Cardiogenic—If your dog has fluid in their lungs caused by heart disease, your veterinarian will likely prescribe a diuretic medication to help remove the fluid. Other treatments include oxygen therapy, mechanical ventilation, rest, and diet change.

• Noncardiogenic—Treatment for pulmonary edema unrelated to a heart condition depends on the underlying cause. For example, if an airway obstruction is present, your vet may need to perform surgery to remove the object. If your dog has bacterial pneumonia, they may need antibiotics to help clear the infection. Other potential treatments for fluid in the lungs in dogs include anti-inflammatory medications and oxygen therapy.

In a severe case of pulmonary edema, a vet may remove the accumulated fluid in a procedure called a thoracocentesis to help your dog breathe more easily. This process involves placing a needle or catheter in your dog’s chest to drain the fluid.

Recovery and Management of Fluid in the Lungs in Dogs

Unfortunately, heart conditions such as DMVD and DCM are not curable, but they can be managed to keep pulmonary edema under control.

If your dog has a heart condition, be sure to follow your veterinarian’s recommendations fully, schedule frequent rechecks, and monitor your pup for signs such as lethargy, decreased appetite, and difficulty breathing.

In some noncardiogenic pulmonary edema cases, fluid in the lungs in dogs can resolve quickly while other issues can cause a prolonged recovery. In addition, pulmonary edema may recur, depending on the underlying cause.

Allowing your dog time to rest and recover is crucial once the pulmonary edema is resolved.

Finish all prescribed medications to help prevent recurrence.

Prevention of Fluid in the Lungs in Dogs

In many cases, preventing fluid in the lungs in dogs isn’t possible. However, you can help reduce your pup’s pulmonary edema risk by following these tips:

• Keep your dog at a healthy weight to lower their risk of developing a heart condition.

• Schedule yearly or biannual wellness exams to help detect issues such as heart disease in the early stages, when they are easier to manage.

• Provide year-round heartworm prevention.