When a blood clot blocks a blood vessel of the lungs, it is called a pulmonary thromboembolism. Dogs at risk for a pulmonary thromboembolism include those that are critically ill or those with certain diseases, including immune-mediated hemolytic anemia, bacterial infections, protein-losing diseases, certain heart diseases, severe pancreatitis, cancer, diabetes mellitus, Cushing disease, hypothyroidism, heartworm disease, or clotting disorders. Dogs that receive corticosteroids, that have sustained a significant injury, or that have undergone a major surgery may also have an increased risk. Pulmonary thromboembolism can cause life-threatening heart and lung dysfunction.
Signs vary based on the extent of heart and lung dysfunction. Labored or fast breathing and depression are common. Other signs include coughing (sometimes with blood), blue-tinged gums or skin, collapse, shock, and sudden death. Pulmonary thromboembolism is difficult to diagnose because signs and test results resemble those seen with other diseases. X-rays, echocardiography (an ultrasound of the heart), and other specialized tests may be helpful.
Treatment is aimed at supporting the heart, blood vessels, and lungs. Drugs that inhibit clotting may be used to prevent additional blood clots. Oxygen and medications (such as bronchodilators) are used to improve the amount of oxygen in the blood. Medications used in people to dissolve blood clots are not commonly used in animals.
Also see professional content regarding pulmonary thromboembolism.