Collection of Fluid in the Lungs (Not Due to Heart Disease) in Cats

Noncardiogenic Pulmonary Edema in Cats

Noncardiogenic edema is caused by an increased permeability (or the ability to pass through, as by osmosis) of the blood vessels of the lungs. This increased permeability results in the leakage of fluid into the lung, causing edema, or swelling. This increased permeability results in the leakage of fluid into the lung, causing edema, or swelling. When this becomes severe, the edema may be accompanied by an inflammatory response and an accumulation of inflammatory cells in the lung.

There are several factors which can cause changes in the permeability of the lung’s blood vessels. Cats that have edema as a result of brain disorder, electric cord bite, or upper airway obstruction might experience a systemic release of catecholamines (neurotransmitters and hormones). This release would lead to a causative effect, with systemic constriction of blood vessels shunting blood into the lungs and overloading the blood vessels of the lung, damaging them, and leading to inflammation and swelling of the lungs.

Manifestation of a generalized inflammatory response in the lungs develops in patients with a bacterial infection of the blood, or with pancreatitis, and will often worsen over the 24 hours following the initial episode. The most seriously affected patients may progress from apparently normal health to a fatal condition only hours after the incident.

Symptoms and Types

  • Difficulty breathing
  • Increased breathing rate
  • Standing in unusual positions to breathe better
  • Pale, or bluish gums
  • Spitting up pink, frothy saliva, or bubbles of saliva
  • Increased rate of heart beat


  • Upper airway obstruction
  • Acute neurologic disease (brain disorders)
    • Head trauma
    • Prolonged seizures
  • Systemic inflammatory response syndrome
  • Electric cord bite injury
  • Smoke inhalation
  • Aspiration pneumonia (sucking fluid back into the lungs)
  • Severe allergic reaction


You will need to give a thorough history of your cat's health, onset of symptoms, and possible incidents that might have precipitated/preceded this condition. The history you provide may give your veterinarian clues as to which organs are causing secondary symptoms.

He or she will perform a complete physical exam on your cat, including a chemical blood profile, a complete blood count, a urinalysis and an electrolyte panel. Arterial blood gas measurement, and pulse oximetry will also be performed, along with coagulation testing (to determine whether the blood is clotting normally). Radiograph images of the thoracic (chest) cavity are also essential for making a definitive diagnosis. An echocardiogram may also be performed to rule out, or confirm, pulmonary (lung) edema caused by heart disease.

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