Coughing

What is a cough?

A cough is an expiratory effort producing a sudden, noisy expulsion of air from the lungs, usually in an effort to free the lungs of some foreign material (real or imagined).  This can sometimes be confused with retching or gagging, although occasionally an animal may retch or actually vomit following a forceful bout of coughing.  The presence of a retch may be misinterpreted as evidence of a problem with the digestive system.

Why do cats cough?

In cats, coughing is generally regarded as a sign of a problem affecting the lower respiratory tract, especially some form of bronchitis.  Cats can cough for a variety of reasons, including the presence of foreign material within the airway (e.g. pieces of inhaled grass), or irritation from inhaled liquids or gases.  Coughing can also result from inflammation of the airway, which may be acute (e.g. cat 'flu) or more chronic (e.g. chronic bronchitis/asthma).  The inflammation may be caused by a number of factors, including viral, bacterial, or parasitic worm infections, or may be associated with an allergic reaction.  Tumours (cancer) located within the chest can occasionally cause coughing.  Heart disease rarely causes cats to cough.

Coughing can also be seen with upper respiratory tract disease, e.g. where irritation, inflammation or other disease affects the larynx or trachea, or where disease in the nose results in excessive secretions draining into the larynx and trachea, hence causing irritation and coughing.

When does a coughing cat need veterinary attention?

It is normal for cats to cough very occasionally, e.g. when they inhale foreign objects, or if their airway becomes irritated by changes in the environment.  However, if the cough persists for more than a few days, or intermittently occurs over a few weeks or months, is severe, productive (i.e. the cat spits something out), is accompanied by changes in the cats breathing such as increased rate or effort of breathing, the cat appears unwell in itself, or is losing weight or showing any other signs, then veterinary attention should be sort.

How can the vet find the cause of a cat's cough?

Most acute cases of coughing will cure with minimum need for interference, except for perhaps a few days of antibiotics.  However, if the cough is very severe, or if it has been present for some time, then further investigation may be needed.  This usually entails taking a full and detailed history in which the vet will need to know whether the cough has changed over time, and whether the cat has any other medical problems that may be significant.  The next step in the investigations is radiographs of the chest.  This may require sedation or anaesthesia.  If the cat is anaesthetized, the vet may look down its airway with an endoscope.  Samples of fluid and cells can be collected from the airway, either via the endoscope, or by flushing a small amount of sterile salt solution into the lungs and then sucking it back out again.  These samples can be used to look for the presence of infection, inflammation or tumours.

How can the cough be treated?

How a particular cat is treated depends on the cause of its cough, for example removal of a piece of foreign material, treatment for lung worm infection, antibiotics for bacterial infeciton, and anti-inflammatories for chronic bronchitis/asthma.

Chronic coughing is associated with chronic inflammation of the airway, often due to chronic exposure to allergens (particles to which the cat is allergic), irritants (e.g. cigarette smoke), or bacterial infection.  This chronic exposure results in a number of changes in the structure of the cat’s airway, such that even if the initial trigger can be identified and removed, the damage has already been done and the lungs can never fully recover.  In these cases treatment aims to control the coughing, and prevent further damage, but the condition may not be able to be cured.  Treatment may include removing any known irritants or allergens, giving drugs to help keep the airways open, treating bacterial infections with antibiotics, reducing inflammation with corticosteroids, and sometimes giving decongestants.  Recently a special inhaler spacer chamber has been developed for cats to enable administration of inhalational drugs (such as used for the treatment of asthma in humans), which have the advantage of delivering high concentrations of the drug to the area where it is required (the lungs) without it being absorbed into the circulation and risking systemic side effects that may occur when some orally administered drugs are required long term.