Wonderful!! Thanks for all the answers.
You sure sound like you could be doing all the tests.
You haven't left me much to work with
Well the three major things we think about in chronic coughing cats are heart disease; chronic bronchitis; and asthma. An usual cause is a lung worm
, which can be hard to diagnose.
I anticipate the vets would have noted heart disease and the xrays did not sound consistent with that, so that is less likely. And it happens less frequently than other causes.
Chronic bronchitis and asthma are still left and can go together over time.
Chronic bronchitis is defined as a cough of longterm (several weeks) duration, that may respond intermittently to therapy, but come back again. It consists of a chronic inflammation of the airways and can result in a non-productive (no mucus) chronic cough. Due to the damaged airways, they can be more susceptible to bacterial infection.
Because of a possiblity of lungworm, we sometimes do a trial course of fenbendazole, an antiparasite drug. Often on the bronchial wash, we will see a cell called eosinophils, but it sounds like they did not see this.
At this stage, I would retry a bronchial wash with cytology and culture to see if any change have occured and it should be done during the actual coughing episiodes.
The reason for this is because your cat is having recurring events and we have not found an answer.
Short of that, I would recommend a course of treatment with a bronchodilator, one that is used is theophylline, which is a tablet. This may help decrease lung spasm and allow the airways to rest a little bit. An alternative is there are pediatric masks for astham a type inhalers that can be used for cats.
If there is limited response to the aminophylline, steroids can be used, this really is to help break up the inflammatory cycle.
One could try a course of fenbendazole for potential lungworms, but this is unlikely as your cat is inside most of the time and they get these from snails. If a bronchial wash came back with eosinophils..then I would do this.
These are some suggestions as how I would approach.. Since this is ongoing, you may need to try several different strategies for diagnosis and treatment.
A lot here. Let me know if you need clarification or have more questions.