Introduction

Cats suffering from asthma often wheeze, cough, sneeze, have shortness of breath and display other signs associated with oxygen deprivation (cyanosis). As frightening as these symptoms can be to owners, they are also the primary determinants for diagnosing feline asthma.

How Feline Asthma is Diagnosed

There is no single test that will conclusively confirm whether a cat has asthma or some other respiratory condition. A diagnosis of feline asthma is made based upon a number of factors, including the cat’s clinical signs, a thorough veterinary physical examination and history and ruling out other disorders that could cause or contribute to the symptoms, such as infectious pneumonia, cancer, heartworm disease or lung parasites.

The results of routine blood work (complete blood count and serum biochemistry profile) typically are normal in affected animals, although certain white blood cells called eosinophils may be elevated if heart or lung parasites are present. Other laboratory tests, such as fecal flotation and heartworm testing, may also be helpful if parasites are involved. Intradermal skin testing to identify the cause(s) of asthma has not proven promising in cats.

Thoracic radiographs (chest X-rays) are extremely important to the diagnosis of feline asthma. Chest films may show evidence of inflammatory lung damage, infection or scarring, or they may appear normal. The presence, absence or severity of radiographic changes does not necessarily correlate with the seriousness of the cat’s disease. An echocardiogram can be used to evaluate the possibility of heartworm infection or other possible heart involvement. This is a non-invasive test that most cats tolerate quite well. Sedation is commonly necessary to quiet the cat for these procedures.

Other, more advanced tests that may help to confirm or rule out feline asthma include transtracheal wash (TTW), bronchoalveolar lavage (BAL) or bronchoscopy with specimen collection, and urine evaluation to assess systemic health and overall organ function. The samples obtained through TTW, BAL and/or bronchoscopy are assessed microscopically through a procedure called cytology, during which a pathologist or pathology technician analyzes the sample at a cellular level. If abnormal levels of bacteria are found, they can be cultured (grown) in the laboratory, to identify the particular bacterial species so that an appropriate antibiotic can be prescribed. Lung biopsy is also available, although it is rarely used in cats because it is so invasive and typically is not necessary. Sometimes, a positive response to medical treatment will help to confirm a diagnosis of asthma, when other tests are inconclusive. Fortunately, feline asthma typically can be treated successfully, with lifelong medical therapy.

Special Notes

Owners should keep notes of when their cats show clinical signs of asthma, and the nature and extent of those signs. This can be quite helpful to the attending veterinarian, especially to help establish any seasonality of exposure to inciting allergens.