Cat cough

Question
Dr. Fry-  
  Hi. I have a 16 Yr old DSH. For the past month or so she has been coughing quite a bit and sometimes even throws up clear liquid and white stuff.I have seen her struggle to swallow at times.
  I had her to the vet about a month ago where she had a tooth removed. They did bloodwork and a UA on her that indicated a slight kidney problem. It did not indicate a thyroid or diabetic issue. During her visit for the tooth, I told them how the cough was starting, but they couldn't find anything.
  Her coughing is becoming more frequent. Her throwing up this liquid is different. Not to be gross, but you know how a cat goes thru that big production before throwing up? Well, I saw her this morning just lean over w/o the whole production and cough up that clear liquid.
  May cat's appetite is very good, but for years now the she has been losing weight. I keep feeding her more and more, but she can't gain weight. She's very thin looking and weighs just a little over 7 lbs. Her water intake has increased as well. The vet said the weight loss and increase in water intake may be due to the kidney problem and a change in metabolism from it. Otherwise, her energy and spirits are good!
 Does it sound like my cat has a respiratory problem? What would you suggest? I would appreciate your advice.
              -Lisa
               Plymouth Meeting,PA

Answer
Hello Lisa.

I would recommend x-rays of her chest and abdomen.  She could have asthma that is causing the coughing.  She could also have inflammatory bowel disease that is causing the vomiting.  If one or both or diagnosed, usually prednisone is prescribed to reduce the inflammation and subsequent weight gain will occur.   The weight loss and increased thirst is most likely due to her underlying kidney disease, but I would recommend a urine culture to make sure she isn't brewing an infection.   If she will eat Hills K/D or Royal Canin Renal LP that would be good for her kidneys to reduce the workload and may help her gain weight.   Not to scare you, but since she is older, there certainly is a possibility of cancer leading to the weight loss.

Good luck,
Dr. Fry