Feline Heart and Lung Diseases
Hypertrophic Cardiomyopathy
Hypertrophic cardiomyopathy, the most common heart disease in cats, is a condition in which the muscular walls of the heart become abnormally thickened. This causes problems with blood returning from the lungs to the heart. The end result is a backup of fluid into the lungs (pulmonary edema) or chest cavity (pleural effusion). This fluid backup is also called congestive heart failure.
Symptoms
This disease usually affects middle-aged to older cats. Signs can initially be very subtle, such as a mildly increased breathing rate (normal is less than 30 breaths per minute when at rest) or weight loss. As the disease progresses more pronounced symptoms, including exercise intolerance or significant breathing difficulty, can be noted. It is also possible for your cat to exhibit stroke-like signs if a thromboembolism (blood clot) develops. Sudden death is also possible.
Treatment
There is no cure for this disease but symptoms can often be managed for a while.
Fluid overload in the lungs (pulmonary edema) is treated with diuretics (such as furosemide) which help the body get rid of the excess fluid, and angiotensin converting enzyme inhibitors (ACE inhibitors such as enalapril) that help to manage blood pressure and eliminate hypertension. Fluid that accumulates in the chest cavity, outside of the lungs, can be removed with a catheter. Additional medications may help the heart muscle relax, which in turn may reduce the abnormal fluid backup that occurs with this disease. Blood clots are often managed with anti-clotting agents.
Restrictive Cardiomyopathy/Unclassified Cardiomyopathy
This is a condition in which the muscular walls of the heart become abnormally stiff while retaining their normal thickness. This in turn causes problems with blood returning from the lungs to the heart. The end result is a backup of fluid into the lungs (pulmonary edema) or chest cavity (pleural effusion). This fluid backup is also called congestive heart failure.
Symptoms
Signs can initially be very subtle, such as a mildly increased breathing rate (normally less than 30 breaths per minute when at rest) or weight loss. As the disease progresses more pronounced symptoms, including exercise intolerance or significant breathing difficulty, can be noted. It is also possible for your cat to exhibit stroke-like signs if a thromboembolism (blood clot) develops. Sudden death is also possible.
Treatment
There is no cure for this disease but symptoms can often be managed for a while.
Fluid overload in the lungs (pulmonary edema) is treated with diuretics such as furosemide, which help the body get rid of the excess fluid, and angiotensin converting enzyme inhibitors, which help to manage blood pressure. Fluid that accumulates in the chest cavity can be removed with a catheter.
Dilated Cardiomyopathy
This is now a rare disease in which the muscular walls of the heart become abnormally thin and weak leading eventually to enlargement (dilation) of the heart. This in turn causes problems with blood returning from the lungs to the heart. The end result is a backup of fluid into the lungs (pulmonary edema) or chest cavity (pleural effusion). This fluid backup is also called congestive heart failure. Some cats with this disease are deficient in taurine, an essential amino acid that cats can only get through their diet. If caught early enough these cats may be cured with taurine supplementation.
Symptoms
Signs can initially be very subtle, such as a mildly increased breathing rate (normally less than 30 breaths per minute when at rest) or weight loss. As the disease progresses more pronounced symptoms, including exercise intolerance or significant breathing difficulty, can be noted. It is also possible for your cat to exhibit stroke-like signs if a thromboembolism (blood clot) develops. Sudden death is also possible.
Treatment
There is no cure for this disease but symptoms can often be managed for a while.
Fluid overload in the lungs (pulmonary edema) is treated with diuretics, which help the body get rid of the excess fluid, and angiotensin converting enzyme inhibitors, which counteract overactive compensatory mechanisms in the body that contribute to the fluid overload. Fluid that accumulates in the chest cavity can be removed with a catheter.
Heartworm Disease
Cats acquire heartworm disease when bitten by a mosquito carrying microscopic heartworms. Importantly even indoor cats are at risk for this disease and studies have shown that indoor and outdoor cats have equal risk factors. The microscopic heartworms injected into the cat by the mosquito grow and slowly migrate to the heart and lungs.
Symptoms
Cats with heartworm disease can exhibit a variety of symptoms although some affected cats have no apparent symptoms. Heartworm symptoms can include coughing, vomiting, rapid breathing, or even sudden death.
Treatment
There is no safe direct treatment for this disease in cats, but certain symptoms can be treated. The heartworm’s lifespan is 2-3 years, but changes related to the infection can last for the life of the cat, and the mortality rate in infected cats is ~50%.
Prevention
This is especially important since there is no treatment available. Monthly treatment with topical Revolution, oral Heartgard, or oral Interceptor (among other oral products) is effective for preventative measures.
Feline Asthma
This disease, similar to human asthma, occurs when the small airways in the lungs abnormally constrict. This leads to a decreased ability to bring air (and oxygen) into the lungs. It is important to note that extra weight, stress, increased humidity, dusty cat litter, aerosal products, and any substance that affects air quality, including cigarette smoke, can all exacerbate feline asthma.
Symptoms
Symptoms in cats can initially be very subtle and easy to miss. They include coughing, difficulty breathing, wheezing, decreased activity, an increased breathing rate, and decreased exercise ability. Feline heartworm disease can mimic feline asthma.
Treatment
Since this disease can mimic other respiratory and cardiac conditions your veterinarian will need to run blood work and x-rays to diagnose the disease. Once it has been diagnosed the mainstay of treatment is prednisolone (or other corticosteroids) to decrease inflammation in the small airways and/or a bronchodilator (terbutaline, albuterol, etc) to help open up the airways. These can be given orally or via inhalers.