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Bronchioles, or small airways, are the tubes which carry air into and out of the lungs. The bronchioles can become inflamed, often because of allergies (Harpsie definitely had food allergies, and probably others as well). This inflammation causes a narrowing of the airways, making it harder to breathe. Mucus may also be produced, narrowing the airways even further.
Asthma is a chronic lung disease which cannot be cured but which can usually be controlled. However, about 10% of cats with asthma die of the condition or are put to sleep because it cannot be controlled; so it must be taken seriously.
Most asthma sufferers have a number of different triggers i.e. things that irritate their airways and trigger their symptoms. In cats, these include smoke, fragrances (including those added to cat litter), chemicals such as paint, dust or dust mites, humidity or cold air.
Research is currently being undertaken to see whether a bacterial infection called mycoplasma is a factor in the development of feline asthma. Vet Click Veterinary News has a report on this research.
Asthma is chronic, i.e. the cat has asthma permanently. However, if a cat is exposed to a trigger, this can narrow the airways suddenly and cause what is commonly referred to as an asthma attack (i.e. an acute attack).
There are actually two main types of asthma attack in humans. There is the classic "wheezing" version which everybody has heard of; but there is also "coughing" asthma. Cats with asthma may also wheeze or cough, but in cats coughing is actually more common than wheezing. Breathlessness may be seen with either type of asthma. If your cat is squatting with the neck extended, gagging and swallowing, it could be an asthma attack. If your cat is open mouth breathing, this may indicate a severe asthma attack or heart problems; either way, it is a medical emergency.
Feline Asthma has helpful information about the symptoms of asthma seen in cats.
The most commonly used way to diagnose asthma in cats is via chest x-rays. These will usually show the signs of inflammation associated with asthma. Asthmatics tend to have problems breathing out, and therefore the lungs may look over-inflated on x-ray. If your vet says he can see "doughnuts" and "tramlines", he is seeing classic symptoms of asthma.
Since some asthmatic cats have normal x-rays, your vet may also want to perform a tracheal wash. There is something similar called a bronchoalveolar lavage (BAL). If cells called eosinophils are found in large numbers, this is commonly a sign of asthma.
A tracheal wash or a BAL can only be performed under anaesthesia, which may be potentially risky for a cat with breathing difficulties. The procedure itself may also cause problems: Bronchodilators in bronchoscopy-induced airflow limitation in allergen-sensitised cats (2005) Kirschvink N, Leemans J, Delvaux F, Snaps F, Clercx C, Gustin P Journal of Veterinary Internal Medicine 19(2) pp161-7 reported that "bronchoscopy and BAL induce airflow limitation in cats, which is more severe in the presence of lower airway inflammation".
Feline Asthma has more information about diagnosing asthma.
In most cases, feline asthma can be managed at home. If the cat has mild asthma, steroids and/or daily medication may not be necessary. However, in many cases inhaled steroid medications are given daily, the goal being to prevent an asthma attack from occurring by reducing inflammation - these are known as preventer treatments.
Sometimes, however, a cat can still have an asthma attack even while taking preventer treatments - often the attack will be caused by exposure to one of the cat's triggers. In such situations, reliever treatments (usually a bronchodilator) are used to open up the airways as quickly as possible.
Dr Philip Padrid discusses the best type of treatment for cats depending upon the severity of their asthma symptoms.
Occasionally a cat will have a major crisis during which reliever treatments do not work as well as is necessary. In this situation, the cat will need to be hospitalised for emergency treatment.
Feline Asthma has information on commonly used treatments.
Fritz the Brave has information on the treatment of asthma emergencies at the vet's.
Because asthma is an inflammatory disease, steroids are usually necessary to dampen down the inflammation. In many cases, they will be given daily.
In humans, steroid inhalers are used which take the steroids to the lungs only and which therefore avoid the problems associated with steroids reaching the rest of the body. Until recently, this was not possible for cats and steroids had to be given to them orally or via injection. However, there is now an inhaler available for cats called Aerokat which has transformed feline asthma treatment. We are using this on Karma who was diagnosed with asthma in summer 2007.
Aerokat has more information about this treatment.
Feline Advisory Bureau shows how to use the Aerokat chamber.
Dr Philip Padrid gives a protocol for use of inhaled meds.
Bronchodilators work by relaxing the muscles of the airways. In Harpsie's case, a bronchodilator was sufficient to keep his airways open and working. Harpsie received one tablet daily.
It is also possible to give bronchodilators via inhaler, as described in the Steroids section, and this is more helpful if you are using the bronchodilator to relieve an asthma attack.
We used etamiphylline (Millophyline-V) for Harpsie; other common bronchodilators are terbutaline (Brethine) and theophylline (Theo-Dur). For inhaled medications, albuterol is commonly used.
Veterinary Partner has information on the use of theophylline.
Histamine is produced as part of an allergic response. Antihistamines reduce the effects of histamine, but it appears that they are less effective in cats than in other species. However cyproheptadine appears to have unique features that make it helpful for cats with asthma, particularly for cats who do not fully respond to steroid treatment. Unfortunately it can also have several side effects, such as making the cat agitated, causing howling etc., or having the opposite effect of causing lethargy.
Cyproheptadine is available in Canada without a prescription, but please do not use it on your cat without your vet's knowledge and approval.
Pet Education has information on the use of cyproheptadine in cats.
Pet Place also provides an overview.
Acupuncture may help with feline asthma, and in some cases you may even be able to reduce the dose of medication (though this should only ever be done with your vet's full knowledge and approval).
Harpsie received acupuncture for his arthritis, you can find more information about it here, including how to find a veterinary acupuncturist.
Feline Asthma has some information about the use of acupuncture.
Mar Vista Vet has an excellent overview of asthma in cats
Feline Asthma is a very helpful website about asthma.
Feline Advisory Bureau has detailed information about feline asthma.
Feline asthma - chronic bronchitis in your cat is a helpful overview of asthma by Dr Ron Hines.
Fritz the Brave has a lot of information about the use of inhaled medications.
The Winn Feline Foundation has a helpful summary of the main issues with asthma.
Feline Asthma Inhaled Meds is a support group for people using inhaled medications on their asthmatic cat.
Harpsie is a Persian, with a relatively flat face, so initially we thought his snorting noises were down to that. But our vet did wonder once or twice whether Harpsie might have asthma. Since it was thought that Harpsie had heart disease (he seemed to struggle to climb the stairs and was breathless), Harpsie was put on heart medications, including a bronchodilator, when he was seven years old. This probably helped his asthma without us realising it.
When Harpsie was nine years old, we took him to the cardiologist and after he ran his tests on Harpsie he told us that, judging by changes in Harpsie's lungs which he could see, he believed that Harpsie had asthma. However, Harpsie never had an asthma attack as such (i.e. breathing difficulties or coughing spells), so it was decided we would simply continue giving him his bronchodilator medication.
Harpsie continued to cope well with his asthma. After we moved to the USA in 2004, it was finally determined that in fact Harpsie did not have heart disease, so he was able to have a much needed dental. The vet offered to do a tracheal wash while Harpsie was under the anaesthetic, to which we agreed. The tracheal wash indicated that Harpsie had a lung infection, and also that he had signs of asthma. But the symptoms looked mild, so the vet suggested that perhaps we could reduce the dose of bronchodilator because she said Harpsie was actually on a very high dose. However, we opted not to do this because Harpsie had by now been on this medication for five years, and we did not want to rock the boat.
The tracheal wash caused problems and Harpsie ended up being rushed to the hospital three days later as an emergency - you can read more about it here.
Although Harpsie recovered from his crisis, he began to have another one in October 2004, about a month after the dental and the tracheal wash. He was breathing very heavily and fast and we had to take him to the hospital twice in 24 hours. They believed Harpsie was having an asthma attack on each occasion (his lungs were over-inflated), although they also believed something else was going on. He was placed in an oxygen tent on both occasions, and when he was discharged after the first visit, his asthma medication was changed to Brethine (terbutaline). During our second visit to the hospital, they checked him and ascertained that his respiration rate (which should be 30-40 pm) was 100 pm. Harpsie was admitted, and 36 hours after his first Brethine dose, he had his first ever seizure.
I was asked if I would like to have Harpsie's lungs examined under anaesthesia, but I declined because I was not sure he could survive it, so instead they started him on antibiotics in case the lung infection he had had a few weeks earlier was part of the problem. Besides, this was just a guess they were making.
It was later determined that Harpsie had epilepsy, but Brethine (like all bronchodilators) can lower the seizure threshold so I will always wonder if this was a factor in Harpsie having seizures. However, the Brethine had been stopped about 40 hours after Harpsie had first been put on it because his heart was racing and Brethine can be the cause of that; so they had stopped it and his heart rate had returned to normal.
Harpsie was poorly at the beginning of February 2006, with severe vomiting and discomfort. We ascribed this to switching from the UK to the US version of his broncho-dilator, because he vomited within ten minutes of being given the US version. With some difficulty I managed to obtain additional supplies of the UK version and the vomiting stopped, and Harpsie seemed to be doing well.
Harpsie once again developed breathing difficulties later that month (February 2006). In the end it did not appear to be asthma-related, but rather appeared to be associated with severe constipation and phenobarbital toxicity (you can read about it here). Ten weeks later Harpsie was diagnosed with cancer, including secondary lung cancer, which ultimately took his life on 23rd May 2006.
Thus, although Harpsie had asthma for much of his life, it did not appear to cause him major problems, but nevertheless lung problems were basically the reason for his demise.
This page last updated: 11 February 2008
Links on this page last checked: 2 February 2008
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