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Pet Owner Version

Pulmonary Thromboembolism in Cats


Ned F. Kuehn

, DVM, MS, DACVIM, Michigan Veterinary Specialists

Reviewed/Revised Aug 2018 | Modified Oct 2022

Pulmonary thromboembolism Blood Clots and Aneurysms in Cats A thrombus is a blood clot that may form when the blood flow of an artery or vein is restricted, when the lining of a blood vessel is damaged, or when another condition causes a cat to produce... read more is the blockage of one or more blood vessels in the lungs by a blood clot. Certain diseases (such as cancer and heart disease) and critical illnesses can put cats at increased risk for developing this potentially life-threatening condition. When the blood vessel blockage is significant, severe circulatory and respiratory changes can develop.

Signs vary depending on the severity of the blockage. Labored breathing, rapid breathing, and depression are common. Coughing, blue-tinged mucous membranes and gums, coughing up blood, collapse, shock, and sudden death can also occur.

Pulmonary thromboembolism is underdiagnosed and also difficult to diagnose because the signs are similar to other conditions. Chest x-rays, blood gas analysis, and echocardiography (an ultrasound of the heart) are helpful but may not be able to confirm the diagnosis.

Treatment for a pulmonary thromboembolism should begin as soon as possible. Medications to prevent clotting may be given. Oxygen supplementation and medications to enlarge airways can support the respiratory system. Medications used to treat high blood pressure in the blood vessels of the lungs may also be necessary. Medications used to dissolve blood clots in people are not routinely used in veterinary medicine, but they could potentially improve survival in severely affected animals.

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