Respiratory issues in cats can range from a wide variety of problems such as asthma, polyps, heart disease, cancer, and infections whether viral, bacterial, or parasitic.
Feline asthma is caused by inflammation of the lower airways. It can be acute or chronic and presents with symptoms such as coughing, sneezing, labored breathing, or wheezing.
Nasal and nasopharyngeal polyps are usually non-malignant masses that arise from a stalk like growth from the epithelial layer. They can result in chronic nasal discharge and congestion, noisy breathing, chronic ear infections, voice changes, head tilts and horner’s syndrome.
Heart disease as a cause of respiratory issues can be secondary to heartworm disease and conditions such as hypertrophic cardiomyopathy and dilated cardiomyopathy. Hypertrophic cardiomyopathy leads to a dysfunctional filling of the heart due to a thickened and non-compliant left ventricle. This results in a chain of physiologic changes that can lead to fluid in the lungs and signs such as shortness of breath, exercise intolerance, anorexia, collapse, blood clots to the hindlimbs,and sudden death. Dilated cardiomyopathy leads to dysfunctional pumping of the heart due to failure of the cardiac muscle from dilation and volume overload. Dilated cardiomyopathy is less commonly seen in cats now that taurine is added to all commercial cat foods. The presentation can be similar to that of hypertrophic cardiomyopathy.
Cancer whether primary or secondary in the heart and lungs can also result in respiratory issues due to space occupying issues leading to less functional airspace or fluid overload from a cardiac tumor.
Viral infectious diseases such as feline herpesvirus and calicivirus can cause respiratory issues due to inflammation, congestion, and ulceration of the upper airways. Bacterial infectious disease such as mycoplasma and bordatella can result in fevers, cough, nasal discharge, and respiratory difficulty.