Anemia and leukopenia in older rabbit

Question
Hi, I had brought my bonded pair in to the vet today because someone has been drinking and peeing more over the last several weeks. I suspected my neutered male Loki who is approximately 7 years old, as I also noticed that he felt more thin. While his lady love is fine, Loki was found to have pale gums and had lost around 3/4 lb since last November. His chem panel was well within limits, but a CBC showed low red blood cells (4.20 M/microliter) and very low white blood cells (2.07 K/microliter). The only thing noticed on multiple x-ray views was mild arthritis, which was already evident. My vet sent him home on Cipro in case the low WBC is from infection and he is scheduled for a recheck on his blood values next week. If the CBC is still bad we'll talk about pros/cons of bone marrow biopsy. He is currently bouncing around the living room and snuggling with his lady love as normal, aside from being annoyed by being harassed and given medicine.

History: Adopted and neutered at about 1 year old, just over 6 years ago. Small, self-resolving fibroma last November. Regular grinding of molar spurs for the last three years with annual kidney/liver blood value checks: all normal. Diet of 1/8 cup timothy pellets with massive quantities of grass hay and fresh greens.

I'm worried about cancer here, as is the vet. Are there any other possible causes for anemia and leukopenia in a rabbit with functioning kidneys and liver? If we are looking at cancer, what can I do to help his quality of life (versus extending it at the expense of quality)?

Answer
Dear Angela,

If his kidney values were normal (my first guess, given the PU/PD (polyuria/polydypsia, which is a fancy term for "lots of peeing and lots of drinking") and anemia, would be renal failure), then cancer is a possibility.  But sometimes kidneys can be slowly failing and the B.U.N. and creatinine values not show up as abnormal right away.  A bunny can often manage failing kidneys pretty well on his own by drinking more water.  So be sure he always has lots of clean water available.

If this is a cancer, there is little you can do except spoil him and make him as happy and comfortable as possible.  Since there's no evidence of a tumor, this could be a diffuse type of cancer, such as a leukemia (I've never heard of this in a rabbit, but I suppose it's not impossible) or lymphoma.  The vet may know of blood tests that could be done to determine whether these are likely, but I don't know what they are.

I hope your boy will be fine.  In the meantime, lots of support, good food (free choice, since he's losing weight) and lots of fresh water will help keep him feeling as well as possible.

Hope this helps.

Dana