Siamese Body Change

Question
my female siamese turns 12 yrs old this month. About 6 months ago she began to gain weight rapidly.  She went from 7 to 9 pounds in about 2-3 months.   Her breathing became quite labored and noisy.  Her eating and drinking habits have not changed.  Her stool and urination habits have not changed nor have her activity levels changed. I took her to the vet about 3 months into the weight gain and he ran several tests, did blood work, etc., and but said there is nothing wrong with her. The breathing difficuylties and weight gain symptoms have not diminished nor gotten worse but sometimes I worry about her heart with the labored breathing.  I worry about a tumor although the vet says there isn't a tumor.  Are you familiar with these symptoms?  I would really appreciate your assistance.

Answer
SL,

These symptoms are fairly non-specific so I would recommend that you have another vet take a look at this kitty. It sounds as though something is going on and it could be something as serious as congestive heart failure which would cause weight gain due to fluid retention and the heart would have to work harder causing the shortness of breath. I'm not a vet so I'm not qualified to make a diagnosis but in your situation I would seek a second opinion.