There are several diseases that are related to Feline Asthma. Lungworms, heartworms, upper & lower respiratory infections, lung cancer, cardiomyopathy and lymphocytic plasmacytic stomatitis can all mimic asthma symptoms and therefore should be ruled out. Please note that these diseases, particularly heartworm, react favorably to steroid treatment, so you cannot assume that it is in fact asthma simply from a favorable reaction to treatment. Diabetes and kidney disease can result from feline asthma treatment.
Veterinarians have been missing the diagnosis of heartworm disease in cats for years. We long believed that the cat disease was rare, and if seen would look like the dog disease, i.e. progressive cough leading to heart disease, wasting away, followed by death from heart failure. Recently we've learned that only the very rare case of cat heartworm disease looks like this. Because of new testing procedures we have found that feline heartworm disease is much more common than we ever thought. The majority of cases were diagnosed as chronic bronchitis or asthma. In fact if you have a cat who was diagnosed with asthma or chronic bronchitis in the past and was well controlled with cortisone, he may have had heartworm disease. Asthma, chronic bronchitis and heartworm infection cause inflammation of the lungs and all are treated with cortisone. Therefore even if your heartworm infected cat was misdiagnosed as having asthma, he was treated with the appropriate drug for heartworm disease and probably recovered.
Heartworms are parasitic nematodes that require an intermediate host for infection to catsThe route of infection for heartworms is through the skin; they are transmitted to cats by mosquitoes that carry the larvae. Heartworm does cause coughing in some cats. Heartworms are difficult to diagnose. There are two kinds of tests for feline heartworms: antigen and antibody. The antibody test only indicates exposure not infection with worms, which can lead to false positives. The antigen test looks for a specific hormone that the worms release and so it is evidence of a current infection. However, because most cats have a very low worm load, and presumably low circulating antigen levels, the odds of a false negative are good. Cardiac ultrasound is additional diagnostic tool that can also assess the current health of the heart as well as provide an idea about worm load.
Because of a lack of substantial symptoms associated with heartworm disease in cats and the high risk involved in treatment, most often it is recommended that the cat begin heartworm prevention (Heartgard/ivermectin) to prevent the current worms from reproducing while waiting for them to complete their lifespan which is about two years. The death of the worms may be uneventful so that the body absorbs their remains or may cause a cardiovascular obstruction that could be fatal.
Heartgard (active ingredient ivermectin) works to kill the larvae that circulate in the blood vessels before developing into the adult heartworm. Ivermectin has no effect on adult heartworms. Ivermectin toxicity in cats is only a concern at much higher doses than Heartgard provides, is more common when it is injected subcutaneously, and such toxicity is unrelated to current infection with heartworms.
Cancer - From
The symptoms of lung cancer depend on the number and size of the tumors. The one universal symptom is difficult breathing. As the normal lung tissue is destroyed by the growing tumors, the patient tends to exhibit labored breathing that is rapid and shallow. Patients with lung cancer may also experience coughing, occasionally bringing up bloody mucous. In advanced cases, the patient will lose weight and eventually die. As mentioned earlier, other tissues in the cat are usually involved. Other symptoms depend on which other organs or areas of the body are also affected.
True cardiomyopathy will present with the heart as an abnormal shape and fluid may be detected in or around the lungs. If a large amount of fluid is present around the lungs, it may be necessary to remove it and take more radiographs because the presence of this fluid interferes with evaluation of the heart. Ultrasound and electrocardiogram (EKG) are common tests for cardiomypopathy.
Diabetes is a very serious disease and left untreated, causes damage to the heart, kidneys, circulation and causes muscle wasting, and can lead to a premature death. It also leaves the body ripe for opportunist infection, particularly oral and urinary.
Disease/Chronic Renal Failure
Allergies and Asthma