Expert: Jessica - 1/16/2010

Question
we have a 5 year old ragdoll cat.  he has lost weight.  he will eat for a couple of days and then the very same food he was eating all of a sudden he won't eat it.  we have gone to the vet.  done blood work, xrays and ultra sound.  nothing shows up.  we are even giving him pills to stimulate the appetite.   he plays and doesn't particularly act sick, but he is driving us crazy with his on and off again eating.  he is not eating enough to keep a regular weight.  we keep trying new foods, he seems to like cheese (that's today anyway) so we put a little velveta cheese in and he ate a little.  we have spent over 1,000 trying to find out why he is doing this.  nothing has changed at home. his sister is acting fine.  we are afraid we are losing him, but we don't know what else to do.  the vet seems at a loss.  suggesting maybe some type of liver biopsy.  but i am beginning to believe it is behavorial, not physical.  any suggestions.  thank you.

Answer
Hi Marcia.  The only thing I can suggest besides all the tests you've had done is to check for pancreatitis.  This causes anorexia in about 75% of cats and is often the only sign of the illness.  Up to 40% may experience nausea and/or vomiting.

There are a couple of pancreatic enzymes that are measured in standard blood chem tests.  Vets rely heavily on these to determine whether or not the cat is suffering from pancreatitis, and they also look for elevated liver enzymes, since pancreatitis and liver disease can go hand-in-hand.  Unfortunately, none of these tests are very conclusive when it comes to pancreatitis.  Ultrasounds can be a little more helpful, but this is still unreliable.  My experience has been that most regular vets get really stuck on the results of these tests, despite widespread knowledge that they are poor indicators of the presence pancreatitis.  I found this out too late with one of my Siamese and lost him to the disease.  Now, I consult an internal specialist anytime blood tests come out normal but the cat has any degree of anorexia.  He runs a special test called a Spec-FPL.  This is basically an express version of what's called a PLI test.  FPL's give you results in as little as 2 days, while the PLI takes about 10.  The Spec-FPL and the PLI are the ONLY non-invasive tests that are reliable for detecting pancreatitis (if you do a search about pancreatic tests in cats, you may see one called a TLI that is highly accurate, but this is for a different condition, pancreatic insufficiency).  Any vet has access to either the PLI or the Spec-FPL, but some will discourage running the test because it's a monetary investment and you've already had (less accurate) pancreatic tests run.  They run about $100, but I've found the lives of three of my cats worth it!  The only test which can compete is a biopsy of pancreas tissue, but this can worsen pancreatitis and it causes much more stress on the cat, so it's not recommended.

Treatment for pancreatitis is generally supportive.  Subcutaneous or intravenous fluids are recommended by some vets if the cat isn't drinking normally or is vomiting.  These can also help flush irritating enzymes that have leaked out of the pancreas from the system.  This is important, because it's the reason cats feel so poorly.  Some vets also recommend an antibiotic in case the pancreatitis is related to an infection.  The most important factor is to make sure the cat eats small, low-fat meals frequently throughout the day.  A prescription food is recommended, and many cats will need to be force fed, sometimes for a few weeks, until the pancreatitis resolves.

If the Spec-FPL/PLI test comes back normal, you might consider that it could be something behavioral.  I think I would discuss an antidepressant with the vet.  Many of them, such as amitriptyline, also cause increased appetite as a side effect.

Wishing you luck!

Jessica