The Rat Fan Club

This article is from the Rat Health Care booklet. Order one today! Check out the info at Rat Books

Bloating & Megacolon

By Debbie “The Rat Lady” Ducommun

The most common cause of bloating in an adult rat is a tumor in the abdomen. Not only can the tumor cause a bulge in the abdomen, but it can also cause fluid to accumulate in the abdomen. Liver and kidney disease can also cause fluid to build up in the abdomen.

If the abdomen is soft, it may be possible to feel if there is a tumor. (See the internal exam in the booklet.) Some tumors are so soft they can’t be distinguished from normal organs. If the abdomen is tight and hard because of fluid pressure, fluid can be removed from the abdomen by needle aspiration to relieve the pressure. This will then allow palpitation for a tumor, and will also make the rat more comfortable.

Tumors in the abdomen can sometimes be successfully removed surgically, but in many cases, if the rat cannot be kept comfortable, euthanasia is the only choice.

Urinary Blockage

Another possible cause of a rat who looks bloated is an overfilled urinary bladder. This can be caused by bladder stones, prostate disease, or some other problem that prevents urination. Normally the bladder will only be ½" across or less, but if blocked can become 2" across. The bladder is in the center lower abdomen.

Urine can also be drawn out of a large bladder by needle aspiration to make the rat more comfortable while trying to determine the cause of the urinary blockage.

Megacolon

Megacolon is a condition where the nerves to the large intestine don’t work well and so the colon has trouble pushing out feces. This causes the colon to become backed up and both the colon and the stools become larger than normal. Because the stools remain in the intestines longer than normal they can also become drier than normal and this also contributes to the problem. However, diarrhea can also occur. It’s a fairly common problem in rats, usually genetic, and particularly common in black-eyed white rats, or rats with only small spots of color on a white background (rats with the restricted spotting gene).

The condition usually appears in rats 4-6 weeks of age and causes bloating, but can occasionally be found in rats a few months old. In older rats, the colon can feel like two firm masses on either side of the lower abdomen.

Until a few years ago, there was no known treatment for this problem. Then Rat Fan Club member Bonnie Federico, and her vet, Dr. Bill Murphy of the Bayview Animal Hospital in Webster, NY, discovered a treatment when Bonnie’s rat Ed was diagnosed with the problem. Since then, the treatment has been used successfully on 3 baby rats that I know of. There is no cure, but the treatment allows the rat to live a fairly normal life and is fairly inexpensive.

The treatment consists of a natural vegetable laxative called Senekot and a drug called cisapride, which assists the colon in pushing things along. It’s also important to make sure the patient takes in lots of fluids by offering lots of fresh foods. My homemade diet is very helpful. If giving rat blocks, it’s helpful to soak them in water.

Cisapride is no longer available for humans, but it is available from most compounding pharmacists. One I can recommend is BCP Veterinary Pharmacy in Houston at 800-481-1729. You will need your vet to call in a prescriptionThe dose is 0.2-0.4 mg/lb. It is best to give the cisapride on an empty stomach, at least 1 hour before or 2 hours after a meal. The suggested dose for the Senekot is 1/8 tablet/lb once a day. This can be given with food.

It is usually also necessary to help the rat have bowel movements. Bonnie discovered that the colon, which runs from under the ribs to the anus in front of the spine, can be squeezed from side to side “like a tube of toothpaste” from top to bottom to help push things along. It may also be necessary to pinch the area just under the tail to help feces come out of the anus. If a rat does get really blocked up, a sliver of a suppository can be inserted into the anus.

Ed’s case was unusual in that he did not have problems as a baby. Instead, his problem was noticed after he was neutered. Because of the surgery, water was withheld for most of the day. Bonnie believes this caused dry stools and resulted the onset of his first blockage. Two days after the surgery she noticed there were no droppings in Ed’s cage. He was treated with fluids and a suppository, which helped him move his bowels. This treatment was required every few days. His stool was often quite hard.

Then they switched Ed from dry rat blocks to my homemade rat diet to add moisture to his diet, and he was encouraged to take in extra liquids.

Although Ed lived with several female rats, Bonnie was able to monitor his stools because they were abnormally large, wide, and squarish looking. She also periodically helped Ed by gently pinching the area between his tail and scrotum when he couldn’t move his bowels on his own. These steps helped return Ed to health and an active life. Cong-rats to Bonnie and Dr. Murphy for their dedication and compassion! Although Ed died at 18 months of age, he lived much longer than he otherwise would have. Because of Bonnie’s patience and compassion, there is now hope for rats with megacolon.

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