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Pleural Effusion in Dogs

Pleural effusion is fluid accumulation in the chest cavity.

Pleural effusion is when abnormal amounts of fluid accumulate in a dog's chest cavity (also called the thoracic cavity) outside of the lungs.

Causes of Pleural Effusion in Dogs

There are two main reasons for fluid accumulation in a dog's chest cavity. Either too much fluid is being produced for some reason, or not enough fluid is being absorbed or removed from the chest by the body.

Here are some of the primary conditions that can cause an overabundance of fluid in the chest, or pleural effusion, in dogs:

  • Heart disease
  • Heartworm
  • Cancer
  • Trauma
  • Twisted lung lobe
  • Infection
  • Hypoalbuminemia (low protein level in the blood)
  • Protein-losing enteropathy (an intestinal disorder)
  • Bleeding disorder or warfarin poisoning
  • Over-hydration (usually the result of intravenous fluid treatment for another condition and concurrent underlying health problems)
  • Liver disease
  • Pancreatitis

Signs of Pleural Effusion in Dogs

When a dog is suffering from abnormal fluid accumulation in the chest cavity, he may show some or all of the following signs:

  • Coughing
  • Open-mouthed breathing
  • Labored breathing, using the abdominal muscles
  • Lethargy
  • Exercise intolerance
  • Pale or blue gum tissue
  • Increased respiratory rate
  • Sitting or lying in unusual positions in an attempt to ease breathing difficulties
  • Decreased energy

Diagnosis of Pleural Effusion in Dogs

To diagnose pleural effusion, a veterinarian first takes a full history of signs from the owner and then does a complete physical exam. He or she might hear muffled heart sounds or wheezes and crackling in the lung fields when using a stethoscope to listen to the chest.

An x-ray will reveal the presence of excessive fluid in the pleural space. A chest ultrasound can also be helpful in diagnosing the presence of liquid.

To determine the cause of the pleural effusion, the veterinarian may use some or all of the following:

  • Blood work results
  • Urinalysis results
  • X-ray and/or ultrasound findings
  • Analysis of fluid removed from the chest with a needle

Treatment of Canine Pleural Effusion

The first priority when treating a dog that is suffering from pleural effusion is to relieve the difficult breathing. This is done by removing some of the fluid from the chest with a needle.

The dog might require oxygen therapy while fluid is being removed.

After that, treatment is aimed at the cause of the fluid accumulation so it can vary widely. It may include placement of a chest tube to drain fluid continuously, pain medications, oxygen therapy, surgery to repair a problem in the chest cavity, antibiotics, antifungals, or anti-parasitics, or placement of a shunt.

For most conditions causing pleural effusion in dogs, the long-term prognosis is guarded to poor, but for some specific problems, diagnosing and fixing the issue can bring about a permanent cure.

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