distressed guinea pig

Question
when i changed my guinea pigs cage last night, i noticed that there were no droppings. i don't understand how he could go days without going to the bathroom. he was making some unusual sounds and hunching his back and looked like he was distressed. after talking to the vet, which didn't help much, and examining his rear-end, we found that his droppings were all backed up inside him. i put him in warm water which helped the droppings come out, but later that night he made the same sound and hunched his back like before. he continues to eat, but doesn't poop any of it out. i'm worried that he will never be able to get any droppings out by himself. is it constipation or something else and what can i do to fix it?

Answer
Hi Danny.  It could be he is impacted, where you found all the droppings backed up inside him.  That area needs to be cleaned out sometimes once a month.  After it is all cleaned out (just use warm water, I know it has an unpleasant odor but there really is no way around it) try to put some vaseline in there to keep it from getting impacted in the future.  However, it sounds like he may have some kind of blockage causing him pain.  The hunching of his back is him trying so hard to push out the feces, and causing him pain in doing so.  Perhaps there is an x-ray the vet can do to see if there is a blockage (or maybe a different vet with more small animal/exotic experience).  Usually impacted boars can still eliminate, it sounds bit more serious than that to me....
Good Luck
Anngela