rat intestinal problems

Question
My daughter has a pet rat that has been heatlhy until recently.  He started swelling around his middle and at first I thought he was just getting fat.  Then I noticed he was sleeping more and wasn't eating much.  Then I examined him a little closer and became concerned that he may have a tumor or cyst.  After praying about the situation, I realized that he hasn't pooped.  i asked my daughter to check his cage for stools when she cleaned it out and she said that there wasn't any at all, though he had been urinating.  So we did a little research and tried giving him some Sene-Lax (about 1/4-1/2 tablet once a day) in the evenings, but it's been almost a week and he still hasn't pooped.  I'm becoming greatly concerned and can't afford the trip to an exotic vet.  What do you recommend?  Could he have intestinal blockage?  Is there a treatment for that?
Thanks so much!

Answer
I am afraid that your rat may have a serious problem.  He really needs to see a vet. Chances are he may have a mass internally and if he is suffering, as a pet owner it is important that you somehow find a way to have him treated.  I hate saying that to people as I know times are so hard for most everyone unless your a Movie star, rock star or a professional athlete, but I have had rats with colon cancer and end up bleeding out of their rectum and in extreme agony and you do not want to go through that. Trust me. You will never sit right with yourself if you have to see your pet rat bleed to death and squeak and scream for hours before he passes away.