33 Constipation Station: Megacolon in Cats

Objectives

1. Understand the gastrointestinal tract structure of the cat
2. Define signs/symptoms of megacolon in cats
3. Demonstrate application of treatment plan

Introduction 

The gastrointestinal tract of the cat starts with the mouth. This is where food is broken up. It then travels to the esophagus where it is pushed into the stomach. Cats have a simple stomach which means they have one stomach that uses digestive enzymes to break down their food. From the stomach, food moves into the small intestine. The small intestine has three parts: duodenum, jejunum, and ileum. All three parts function in absorbing nutrients from the food that was taken in. The next part of the gastrointestinal tract is the large intestine. The large intestine also has three parts: cecum, colon, and rectum. All three parts function in absorbing water from the food.

The parts of the gastrointestinal tract work together to take the nutrients and water out of the food that is being eaten by the cat to be utilized by the body. When one part of the tract is not working correctly then it can cause issues throughout the whole body.

X-ray view of the gastrointestinal tract in a cat: 

Overview of Megacolon

Megacolon in cats is a disease in which the colon remains stretched out, increasing its size to 3-4x the normal diameter, because the muscles are unable to contract. Normally, colon contraction would move feces towards the rectum, an area where the feces sits until it exits the body. Instead, feces is unable to move into the rectum, and instead collects in the colon itself, leading to constipation. Megacolon describes this excessive buildup and size increase.

There can be many different causes of megacolon. These can include something that blocks the GI tract or a spinal cord injury, but, in most cats, the cause remains unknown. A veterinarian can determine if a cat has megacolon by talking to the owner about its symptoms, which can include weight loss, vomiting, a lack of appetite, and problems trying to poop. Dehydration is a common symptom in cats with megacolon, which can cause their poop to be very solid and become obstructed with in their colon.  When making their diagnosis the veterinarian can feel the cat’s belly, as well as x-rays to look at what is going on inside the cat’s colon. Then, they can treat megacolon by giving medications or a specific diet to help the cat poop, giving the cat an enema along with intravenous fluid therapy, or by surgically removing the part of the colon that does not function.

Enemas are injectable fluids used to clean out or stimulate bowel movements in constipated cats. An enema is a thick syringe that is inserted into the rectum of the cat to help flush out the colon. There are different types of enemas that can be used for oil-retention, cleansing, or enema type solutions to help their poop move through the colon/rectum. These enemas should be administered slowly and manual manipulation of the poop may be needed to clear the obstruction.

Watch this video to review the importance of Megacolon

Knowledge Check

Individually complete this worksheet (~10-15 min)

Application Activity (~20-25 min) 

Working with 2-3 other classmates complete this case study. Come up with a problem based on what the owner tells you and how the cat is doing at home. Then come up with a treatment plan for the cat.

Oliver, a 10-year old neutered male cat comes into the clinic. The owner brought the cat in because he has been losing weight, not eating or drinking, vomiting, and having trouble pooping in the litterbox. The owner tells you this has been going on for a couple of days and Oliver has never acted like this before. There is one other cat in the household who is acting normal still and has been pooping in the litterbox normally.

When performing Oliver’s physical exam, you notice that when feeling his abdomen it is very hard and it feels like there is something in his colon. The next step you take is getting some x-rays. Here is the result:

Based on all of this information, what is the problem going on? How are you going to treat this?

Once you have come up with your problem and treatment plan, talk with other groups around you to see if they came up with anything different.