Allergic bronchitis and cats

Feline allergic bronchitis is inflammation of the lower airways, especially the bronchi. The inflammation is often complicated by narrowing of the airways, which is called bronco constriction. This can greatly reduce the intake of oxygen. Allergic bronchitis has two forms. The acute form is associated with reversible inflammatory changes and is also referred to as feline asthma. The chronic form is associated with irreversible airway damage. It can eventually lead to emphysema, a debilitating disease that results from enlargement and dysfunction of the smallest airways and the lungs.

The acute form is usually triggered by a hyperactive immune response to environmental irritants. In most cases, the specific inciting cause is never identified. Most cats are young to middle-age when they’re first affected. The cat usually appears healthy and has no systemic signs of illness. Wheezing and coughing are common signs. If signs are mild and intermittent, the cat may be normal between episodes. Occasionally, episodes of breathing difficulty may progress to become severe and life-threatening. The cat may sit hunched over with the neck extended, trying to take in air.

A tentative diagnosis may be made from the history and physical examination findings. X-rays may or may not reveal changes compatible with allergic bronchitis, but help to rule out other causes of coughing. Examination of airway secretions often identifies inflammation and elevated numbers of white blood cells, especially eosinophils. Bacterial cultures and tests for heartworm and other parasites are often recommended.

Cats in severe respiratory distress require hospitalization and intensive therapy with oxygen. They often need injections of rapid-acting corticosteroids and bronchodilators. Once the cat is stabilized, long-term management is mandatory to control inflammation and prevent or minimize recurrence of the signs. Long-term therapy includes continuation of steroids and the use of bronchodilators. These are often very difficult to administer to cats.

Cats with severe signs often require intense monitoring and hospitalization for several days. Most require periodic monitoring and adjustments of their medications for the rest of their lives. Most respond favorably to therapy, with good control of the clinical signs. Long-term therapy is usually necessary, and occasional relapses are common. If the disease is not controlled, the development of progressive, irreversible changes in the airways and lungs is likely.

Dr. Karsten Fostvedt is a veterinarian at St. Francis Pet Clinic in Ketchum.

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