male bunny has puzzling health problems

Question
  My daughter got our family's first bunny about a month ago. It's a male and we think it is a mini rex. (Probably about 6-8 weeks old when we got it) Did fine for first two weeks then suddenly couldn't stand--legs sprawled out but no head tilt or anything.(We had started him on lettuce and carrots, but stopped when symptoms began.) Next day, he was fine.  Two weeks later he began having trouble standing. Legs not sprawled out this time- just wobbly, falling over, etc. Head doesn't tilt to the side, but at times seems to tilt backwards-we're not sure. He also seems to eat(pellets only) quite a bit and drinks a lot of water.  Seems to have doubled in size in the last few days, and his abdomen seems big. Otherwise, he acts fine-hopping around, very affectionate, etc.  We're puzzled.
  Thanks so much for your help!

Answer
Dear Rhonda,

It would be very unusual for such a young bunny to show sypmtoms of a parasitic infection of Encephalitozoon cuniculi, but this *could* account for symptoms like this.  The condition is treatable with immediate veterinary intervention:

www.bio.miami.edu/hare/fenbendazole.pdf

But there is no guarantee this is due to E. cuniculi.

Is the bunny housed on a slippery surface?  Rabbits, because they have furry bottoms on their feet, need very good traction, such as 100% cotton mats backed with rubber. If bunny is walking on tile, linoleum, wood, or other slick surface, this can damage the connective tissue and ligaments of his pelvic and pectoral girdles (where the rear and front legs attach), and cause "splay leg."  If this is what's going on, be SURE to get bunny on a secure surface, or he will suffer permanent damage.  Please see:

www.bio.miami.edu/hare/splay.html

if the legs are starting to permanently splay.

I would recommend you have the bunny examined by a good, experienced rabbit vet, whom you can find here:

www.rabbit.org/vets

If the bunny truly is drinking excessively (though young bunnies sometimes do), it's possible he ate something toxic and is not only suffering neurological, but also renal damage.  This is something only a vet can treat, so please get him to a good vet ASAP for a complete wellness check.

I hope this helps.  Please write back if you have more questions.

Dana