Cats, especially kittens, often get upper respiratory infections. If your cat shows any signs of respiratory illness, such as sneezing, wheezing, goopy eyes or a runny nose (see box), make an appointment to have the cat evaluated right away. Depending on their cause, upper respiratory infections can quickly become serious, especially in kittens. In adult cats, untreated infections can lead to other (“secondary”) infections or damage delicate sinuses, resulting in chronic problems.