Bronchitis in cats can be caused by a number of different things. As a result, diagnosing this disorder may require a number of different tests to determine what the actual cause of the condition is. A veterinarian presented with a cat that is coughing, lethargic and off its feed will get a thorough history from the cat’s owner, including about when the symptoms started and exactly what the cat has been doing that is different from its normal behavior. The vet will perform a comprehensive physical examination of the kitty. The initial evaluation typically will also include drawing blood and taking urine samples for routine testing (these tests include a complete blood count [CBC], serum biochemistry profile [chem panel] and urinalysis). Blood and urine tests can help identify underlying medical conditions such as feline leukemia or feline immunodeficiency virus, which could adversely affect the cat’s immune system and predispose it to bronchial infection. However, the results of these tests in cats with bronchitis are usually unremarkable. The veterinarian may also recommend taking fecal and/or blood samples to test for evidence of internal parasites, such as heartworms and/or lungworms, which might be the cause of the cat’s cough. Heartworm tests are normally performed in areas where heartworm is pervasive (endemic areas), especially if the cat is both coughing and vomiting. While feline lungworms are rare in the United States, some veterinarians may still want to test for this parasite.
The veterinary physical examination and history are essential in establishing a presumptive diagnosis of bronchial disease in cats. The remaining diagnostic procedures will be focused on trying to find the underlying reason for the cat’s upper airway irritation. Thoracic radiographs (chest X-rays) are usually the first advanced diagnostic tool to evaluate a coughing cat. Cats with bronchitis will have bronchial thickening and other tell-tale signs that will alert the medical team to consider bronchitis as a cause of its symptoms. An echocardiogram can be performed to rule out heart disease as a cause of the cat’s cough. Sampling of the cat’s airway secretions can help to establish the nature and extent of inflammation and/or infection. The samples must be taken from the lower airways and must be done under sedation or general anesthesia. The samples can be taken through several different procedures, including transtracheal wash and bronchoalveolar lavage. Bronchoscopy is the preferred test for evaluating an animal’s airways. This involves inserting a small tube with a camera on its end down through the trachea. It allows the veterinarian to actually see the lining of the airways, and also lets her take samples. Your veterinarian can explain each of these procedures to you in greater detail. Arterial blood gas measurements can be taken to assess the amount of oxygen circulating in the cat’s blood stream if severe respiratory distress is present, although this is uncommon.