The two main reasons that a cat can present to the veterinary practice wheezing are feline asthma and feline chronic bronchitis. Whilst chronic bronchitis is characterised by gradual, progressive changes, cats suffering from feline asthma can present at the veterinary practice as a life-threatening emergency. The challenge for veterinary staff is to recognise these medical conditions and differentiate them from other causes of respiratory distress, so that the cat is treated appropriately, efficiently and as quickly as possible.

Cats that are affected by feline asthma often present at a young age. They sometimes have a history of coughing or wheezing, which owners may confuse with coughing up a furball. Cats that have asthma but are in a stable condition can show no abnormal respiratory signs or effort, but most can produce a cough when the trachea is palpated. At the other end of the spectrum, cats can present in visible respiratory distress, often with a pronounced expiratory wheeze (known as 'status asthmaticus'), and these cats can be cyanotic, open-mouth breathing and sometimes hypersalivating. Vomiting can also follow a violent coughing episode. It is thought in some cases that an allergy might trigger these events.

A diagnosis of feline asthma can often be made on the basis of history, physical examination and diagnostic tests to rule out other disease processes, such as congestive heart failure or feline lungworm (Aelurostrongylus abstrusus), which can cause similar clinical signs. Treatment varies depending on how severely affected the cat is at presentation. For the cat that presents in status asthmaticus, initial treatment includes stabilisation with oxygen therapy and bronchodilators (to relax the airways); minimising handling and stress is of paramount importance. Long-term medical management focuses on the use of bronchodilators and glucocorticoids (to control inflammation). Possible environmental allergens, for example cat litter, cigarette smoke and aerosols, should also be investigated. Such factors may be triggers for an allergic response in a cat with asthma. Ideally the allergen source would be identified and removed. However, this is often not possible because a triggering factor cannot be identified. Prognosis for cats controlled by medical treatment is good, but becomes more guarded for those that suffer severe respiratory distress.

Feline chronic bronchitis, as the name suggests, is a condition that makes slow but permanent changes to the lower respiratory tract. This means that a cat with bronchitis may be less likely to present in respiratory distress, although it is still possible. Clinical signs are similar to those in cats with asthma, so cats can present with a relatively normal physical examination, with a cough and/or possible expiratory wheeze. Once again, owners can mistake these signs for coughing up a furball. With gentle palpation over the trachea, a cough can usually be induced. Diagnostic tests should rule out other conditions, and cytology from a bronchoalveolar lavage (BAL) is recommended for conclusive diagnosis. Medical management of chronic bronchitis is aimed at controlling airway inflammation. Prognosis is improved if the disease is diagnosed early and treatment initiated to slow progression of chronic airway changes.

Inflammatory disease in cats is relatively common, but there are other causes of respiratory distress in cats. Physical examination, history and diagnostic tests such as radiographs and cytology should guide treatment plans.

References

1.  Luis Fuentes V, Johnson LR, et al. BSAVA Manual of Canine and Feline Cardiorespiratory Medicine. 2nd ed. Quedgeley: British Small Animal Veterinary Association, 2010.

2.  Nelson RW, Couto CG. Small Animal Medicine. 4th ed. Philadelphia: Mosby Elsevier, 2009.