Illness & excessive licking

Question
Our 1.5 year old male rat has recently started showing blood in his urine. We took him to the vet, and have had him on an antibiotic (Enrofloxacin) for the last week in case it is a bacterial infection.

This particular antibiotic did clear up an infection he had about 6 months ago, but it doesn't seem to be making any difference this time. Our next steps are a urine culture (to determine infection) or an x-ray (to determine kidney stones or tumor), though he still has another half a week left on this antibiotic regime.

Over the last 4 days or so, he has suddenly started licking me excessively. Our rats have always been very friendly to us and licked quite a bit, but the sick one now will sometimes lick my hands for 5 minutes or more if I let him, which is VERY unusual. Additionally, he has started sometimes eating the "care fresh" litter in his cage (clean) even though there is food available.

My question is whether the sudden excessive licking and/or sudden onset of eating litter suggests anything to you with regard to his sickness. Have you heard of these symptoms before? Do you have any thoughts on whether this might be more suggestive of an infection versus kidney stones or a tumor or some other problem?

Thanks in advance for your help.

Calvin

Answer
 I haven't heard of licking as a symptom unless he is constantly licking himself.  My guess would be that his body is not getting enough of a certain type of nutrient he needs, so he is licking you and eating the bedding in an attempt to get it.  His condition may be robbing him of a certain nutrient or making it harder for him to absorb it from his food.  I don't know too much more about that particular aspect in rats specifically, though I have heard of dogs eating strange things when they are ill for this reason.

 Another possibility is that whatever it is is affecting his brain and anything that affects the brain can change behaviour even just a little bit.  Usually urinary stuff doesn't have much to do with the brain but it may be a cancer that has spread, it's very hard to say.

 I unfortunately can't really tell you any more over the internet.  It's fairly rare for rats to develop urinary problems and I haven't had any personal experience with this.  Though one and a half years isn't that old, it could be that through poor breeding or bad luck with his gene pool he is simply reaching his old age and his organs are losing their function.  Hopefully it is a problem that can be fixed, I am glad you are taking him to the vet.  A culture or x-rays should be able to tell you what the problem is, if the medicine hasn't helped him by the end of the regimen then I would definitely suggest taking him back for more tests.

 If you do find out what it is please let me know!  Good luck!