Feline asthma
The feline 'asthma' gets its name because it shares many clinical features with the disease which humans get. As with humans, feline asthma is a recurring respiratory condition that occurs when the airways in the lung tighten up. This can happen either spontaneously - that is, for no apparent reason - or in response to things which normally should not cause a reaction. In some cases even cold or warm air can induce an attack, but more often grass and tree pollens, smoke, fumes, cigarettes, dust, and aerosols of various sorts such as perfumes, deodorants and flea spray can give asthma to a vulnerable cat. In an attack, excessive mucus forms in the lungs, the airways swell with inflammation and can actually ulcerate, and the muscles in the airway go into spasms leading to constriction. Constricted airways make it impossible to take a deep breath, causing the characteristic asthmatic 'wheezes.' Sometimes none of these signs are visible except the fact that the cat has a low grade chronic cough. Nevertheless, if a cat is susceptible to asthma an acute asthmatic crisis can happen at any time and these crises can be life-threatening.
| Only about one percent of cats develop asthma, but the figure is rising because of increased exposure to environmental pollutants. The chronic bronchitis of feline asthma usually first occurs in cats aged between two and six years old. The problem starts as a slight cough and mild trouble with breathing interspersed with long periods during which the cat seems normal. These early signs can be mild and ongoing . They are not immediately obvious and can easily be overlooked. |
Signs of Feline asthma
- chronic cough
- wheezing
- difficulty in breathing and respiratory distress which occurs suddenly
- increased rate and effort in breathing
Diagnosis
The best way to check is a cat is asthmatic is to watch her breathing. Constricted airways make it difficult for the cat to breathe because the volume of the air which moves in and out is reduced. Therefore an asthmatic cat will flex her abdomen in effort to push more air into her system. Breathing is usually shallow and more rapid. Some cats may even breathe with their months open.
The next step diagnosing asthma is a chest radiograph. Asthmatic cats often have enlarged lungs because air is trapped in them. This so called 'air-trapping' is the result of small airways getting so narrow that the air further down in the lungs cannot be exhaled. Another sign is a flattened-looking diaphragm, caused by over-inflated lungs.
The problem is that changes are not always evident on radiographs, so normal ragiographs do not automatically mean no asthma. Also some cats may be diagnosed with asthma when they don't have it.The diagnosis of asthma can be complicated and the problem is notoriously over-diagnosed because it is consistent with normal radiographs.
If the x-rays don't give enough information, saline can be used to wash cells from deep within the lungs for examination under a microscope (a process called either trans-tracheal wash, bronchial wash, or broncho-alveolar lavage). The presence of large numbers of eosinophils (a type of white blood cells) are characteristic of the disease. But again, here the diagnosis can be complicated because some psitic infections such as lungworm and heartworm also lead to to eosinophil-rich respiratory secretions. So additional tests may be required to rule out these infections.
Treatment
Proper medication will allow an asthmatic cat to lead a normal life. But if untreated, asthma will scar the cat's lungs and airways and may cause permanent damage. A sudden severe attack might even be fatal.
There are three different types of medications for treating feline asthma:
- anti-inflammatory drugs (corticosteroids) - decrease the inflammatory symptoms of feline asthma.
- bronchodilators - relax the muscles that surround the airways, dilating the bronchioles and easing respiration.
- mucholitics - a powder which can be added to food to help to break up the mucus produced in the lungs.
Some cats only need medication during an asthmatic episode but some cats do better with continuous medication a low dosage of the drugs. The good thing is that cats seem to have less serious side effects from long-term corticosteroid treatment than humans. However, they are still likely to put on weight, so a cat on corticosteroids should be watched for signs of obesity. One other thing to bear in mind is that if an asthmatic cat contracts another illness such as bacterial mycoplasma or viral respiratory disease her condition will become much worse. Therefore it is important to shield those cats from opportunistic infection as much as possible by providing a clean hygienic environment.
Note: This information is for guidance only. It is not intended to replace consultation with a licensed practitioner.
