Q: I seem to have a mystery on my hands. This fall, my 3-year-old British Shorthair started losing weight. He slept a lot and didn't eat as much. I took him to the vet to get checked. My cat had a stool check, urine check and complete blood work. His stool was fine. Everything was normal, except for a slightly elevated white blood count, but he had bacteria in his urine and the vet said this may have accounted for the elevation. My veterinarian told me to treat the UTI and then wait awhile as sometimes antibiotics can make the stomach queasy and see if he then started gaining weight.
After two weeks of antibiotics, he seemed better. He has begun to gain weight, but is just not gaining the weight I had hoped for. I can still prominently feel his spine and hip bones. But he eats, plays laser mouse, plays with other cats and uses the litterbox. I have found nothing in the litterbox unusual or concerning. Nothing has changed in the household. I have no toxic plants in the house.
What else should I check? An autoimmune problem or something I've never heard of? I hope it's not cancer in such a young cat, but his blood calcium was normal. I was in touch with the British Shorthair breeder who told me she couldn't think of any disease inherent in that cat breed. My vet offered to set him up with an internist. Should I take him to an internist, and can you think of anything that should be specifically checked?
A: Yes, I do think you should take your cat to an internist. (Full disclosure: I’m an internist, so of course I’m biased.) You’ve described a fair amount of weight loss. Bacteria in the urine indicates a urinary tract infection. A simple UTI would not cause a cat to lose weight. A kidney infection, however, can make a cat pretty sick and could account for the elevated white blood cell count, lethargy (his increased sleeping) and poor appetite. Ideally, the urine should have been cultured, to see what organism was responsible and which antibiotics would treat it best. Regardless, your cat was put on antibiotics and you completed the prescribed course. At that point, a urine culture should have been done to see if the bacteria were gone, and a complete blood count performed, to see if the white count returned to normal.
From your description, it sounds like your cat has returned to normal, behaviorally. He’s eating, he’s active, he’s playing with his toys and interacting with the other cats. Still, the failure to gain the weight back is puzzling, unless he was overweight before and his new weight is the proper weight for him. It doesn’t sound like that’s the case, as you describe a protruding spine and prominent hip bones. This is what you find in cats that have lost significant muscle mass.
I think your cat should have abdominal ultrasound performed. An intestinal disorder such as inflammatory bowel disease could cause a lack of weight gain in your cat. Low-grade intestinal lymphoma also could do this, but it would be very unlikely in a 3-year-old cat. Ultrasound would also provide information regarding the kidneys, to see if there is evidence of a current or recent kidney infection. Ultrasound is a non-invasive procedure and has the potential to provide lots of information regarding your cat’s health. Whether additional tests are warranted after the ultrasound will have to be evaluated by the internist.