2.5yr old chihuahua with swollen stomach

Question
the chihuahua is 2.5 yrs old and has developed a progressively swollen abdominom, occasional diarhea,normal urine, and still has appetite, She is not pregnant. The vet did x-rays no finding, and bloodwork which showed GRA 12.8, RBC 4.75,HGB 11.2,HCT 29.8,MCHC 37.6, ALP 18,BUN 33,GLU 129, TP 5.0, GLOB 1.7. I am foggy as to why the vet could not come up with at least a general diagnosis. Please help. Thanks

Answer
Well one wonders if the simple things have been done first. Sometimes I find they aren't. Is the dog wormed? Is the dog on heartworm prevention? If not has she been tested. What are her liver values? I don't see any in this blood work. A malfunctioning liver will cause fluid build-up in the abdomen. So will heart problems. How does her heart sound? She could have a congenital defect of the heart or liver that is causing this. Chihuahuas are prone to liver shunt problems. Her glucose is a bit high which also makes me suspect her liver.
If your vet isn't giving you a clue then it's time to take her blood work and xrays to another vet and get a second opinion.
Another thought is that apparently she is not spayed, and I see no white blood cell count in this blood work. Could she possibly have pyometra? A massive infection in the uterus that would, on a chihuahua, make her abdomen swollen. They generally act normal with it because it is a sealed infection but they do get diarrhea from it sometimes.
Also her RBC count seems a bit low but I would have to check the values against normals.(it is low but not by much)
Second opinion time is my opinion!