Upper respiratory infections in cats often tend to be lifelong afflictions caused by a herpes virus. Giving lysine at each meal will often bring about a lessening of symptoms. There are a couple of homeopathic remedies that may be useful as well. If the discharge is stringy or ropy, hanging down, Kali bichromicum 30c given twice a day will often help. Silica 30c given daily is often useful in chronic sinus infections.