Megacolon is sometimes wrongly called "Manx Syndrome". Not every Manx has a tendency to develop it nor is it an ailment related only to the Manx. Those cats (Manx or tailless) that show a deformity related to the hind end MAY develop Megacolon. It may also be trauma caused.
Megacolon once was, and still is by some, considered a fatal condition. There was a time when cats diagnosed with megacolon were given a "terminal" prognosis, and the death rate was considered high for this condition. Thank GOD, times have changed!
Megacolon can be deadly, but only if an owner doesn't know what signs to look for or if an owner simply fails to seek help when their cat is obviously ill. But make no mistake; even a cat with severe megacolon can thrive in the hands of an educated human "parent" and their vet. Love, willingness, knowledge and patience will get you and your kitty through anything megacolon has to dish out!
What is Megacolon?
Sometimes the colon loses its ability to contract, and as a result, relaxes and enlarges, resulting in a colon that's much larger in diameter than the anus is. When this happens, stool fills up in the oversized colon and can't easily pass out of the body. And sadly, a majority of the time, the stool can't pass out of the body at all. Over time, the colon continues to draw moisture out of the stool, making the stool harder and even more difficult to pass out of the body. Add to that the fact that additional stool is moving down the intestinal tract towards an already-full colon, and you've got a potentially dangerous situation.
There are different causes of megacolon. A cat with chronic constipation problems can develop megacolon when damage is caused each time constipation occurs. Some cats, like the tailless Manx breed, can be born with hind end abnormalities and lack of sufficient nerves in that area to adequately make the colon contract. Cats born with deformed tails or spina bifida can develop megacolon as well. Injuries to the hind end area can cause nerve damage that makes the colon lose it's ability to contract, or can sustain breaks in bones that can heal improperly and cause a literal obstruction to the anus and colon that can lead to megacolon. And some cats can just develop megacolon out of the blue, usually at an older age, that has no identifiable cause (idiopathic megacolon).
When should you be worried? A cat that strains to defecate. A cat that defecates only every 3-4 days instead of at least once a day. When the stool is hard. When there is blood that accompanies the stool. A simple test of stool impaction or whether it is too hard while still inside the colon is to take your hand and place it across the spine of the cat between the tail and ribcage. Press gently with your thumb and fingers on each side of the spine. You should not be able to feel anything hard in the colon. A normal colon will be relatively soft and the contents should not be much larger than 3/4 of an inch in diameter. If the contents are hard or larger than 3/4" (in an adult cat) then the kitty will need, at the least, a stool softener. At the worst it could be signs of the start of megacolon and a trip to the vet is in order.
A cat with an impaction due to megacolon can develop some life threatening symptoms as the impaction gets worse. Refusing food or water, dehydration (skin that does not snap back when you pull it up and let it go), vomiting , drooling, abdominal swelling, tensing up when the abdomen is touched, frequent trips to the litterbox accompanied by straining yet passing nothing or by passing a brown liquid; all these are serious signs that require immediate veterinary attention.
What will the vet do?
An impacted cat needs immediate unblocking, so the vet will perform an enema. Fluids are given to the cat first to rehydrate the body, and to help start to soften the impacted stool. Some vets may require bloodwork to make sure the cat's overall system is functioning well , at which point an anesthetic is given, and an enema is performed. If the stool is too hard, the vet may have to manually remove the impaction. And in many cases, more than one enema may be required if the stool is severely backed up.
Once the stool is completely cleaned out and your kitty is ready to return home, your job has just begun. Megacolon isn't a one-time occurance, but a condition that requires one of two things: Medical management (treatment) or Surgery.