How to Diagnose and Treat Megacolon in Cats

Reviewed by Natalie Punt, DVM

Last Updated: February 5, 2024

Megacolon is a fairly common issue in cats that occurs when the large intestine (or colon) is distended and filled with feces in a severe form of constipation. Megacolon may occur as the result of another medical condition, or as a condition all its own. If left untreated, this condition can be quite serious as it causes distress to the cat who is unable to toilet properly. Fortunately, your vet can help. By carefully diagnosing and treating feline megacolon, you can relieve your cat's distress and manage their symptoms for a comfortable life.

Method 1

Method 1 of 3:

Diagnosing Megacolon in Cats

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1
Recognize possible causes. By knowing the potential causes of megacolon, you can help to better diagnose your cat.^{[1]
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Research source} Although megacolon sometimes occurs as a primary condition, it usually comes the result of one or more of the following:
- Colon muscles that do not contract normally
- Prolonged constipation
- Physical trauma resulting in a fractured pelvis
- Ingesting non-digestible items
- Neurological disorders
2
Track symptoms. Pay attention to your cat's bathroom behavior. If they have stopped defecating, appear to be having trouble doing so, or seem to be in abdominal pain, there is a chance that they could be suffering from megacolon. If you notice such symptoms, you should seek veterinary care. Any time your cat stops eating or seems unusually lethargic, seek help right away.^{[2]
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Research source} Symptoms of megacolon include:
- Difficulty defecating
- Pain while defecating, accompanied by wincing or meowing
- Blood in fecal matter
- Abdominal pain
- Loss of appetite
- Vomiting
- Defecating outside the litter box
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3
Be prepared to answer some questions. When you visit your vet, plan to bring along some information. In order to properly diagnose your cat, your vet will ask a series of questions.^{[3]
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Research source} Be prepared to describe:
- The complete medical history of the cat (to the best of your knowledge)
- What (if any) medications your cat is currently taking
- What symptoms you have noticed
- When these symptoms began
- If your cat has experienced any physical trauma
4
Run some tests. In order to determine what is going on with your pet, the vet will need to perform a series of tests.^{[4]
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Research source} If your cat is showing symptoms of megacolon, your vet is likely to perform:
- General physical examination
- Rectal examination
- X-rays
- Additional diagnostic tests (such as blood work, urinalysis, and/or ultrasound)

Method 2

Method 2 of 3:

Treating Megacolon in Cats

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1
Determine and address the cause. If your vet is able to determine the underlying cause of megacolon in your cat, the best course of action is for your vet to address this root cause.^{[5]
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Research source} Additional diagnostic tests may be performed to help determine this cause, and a treatment plan will be devised. These tests may include:
- Abdominal ultrasound
- Contrast studies
- Additional blood work
- Colonoscopy
2
Administer an enema. Whether or not a root cause is determined, perhaps the best way to relieve the distress on your cat's colon is for your vet to perform an enema.^{[6]
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Research source} In order to do this:
- Your cat will be placed under anesthesia
- Fluid will be injected into your cat's colon
- The blocked feces will be manually expressed
3
Provide medication. Your vet will likely suggest the use of medication to help relieve your cat's condition and to prevent future constipation. Depending on the nature of your cat's megacolon, you may be asked to continue providing medication after your cat returns home.^{[7]
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Research source} Such medications will likely include:
- Cisapride, which initiates colon contraction
- Lactulose, which acts as a stool softener
4
Perform a colectomy. If your cat's megacolon is especially severe, and/or if other medical treatments have not been successful, your vet may wish to perform a colectomy. This surgery involves removing a portion of your cat's large intestine.^{[8]
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Research source} Should this be needed, be aware that this surgery involves:
- General anesthesia
- An overnight stay in the animal hospital
- Recovery time where you cat will need accommodations
- Significant medical fees

Method 3

Method 3 of 3:

Managing Megacolon

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1
Alter your cat's diet. In order to help heal megacolon, and to help prevent its return, you may be asked to place your cat on a high-fiber diet. Ask your vet for recommended brands and portion guidelines.^{[9]
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Research source}
- Look for cat food labeled "high fiber."
- You can find these at pet stores, grocery stores, through your vet, or online.
2
Ensure proper hydration. Dehydration is a major factor in constipation. In order for your cat to recover from megacolon, it is important for you to monitor their hydration for at least a week after you see your vet. In order to do this, you can:
- Provide fresh water
- Make sure your cat is drinking every day
- Make sure your cat is urinating every day
- Include canned food in their diet
- Add water to their dry food
- Follow any additional instructions from your vet
Note how often your cat relieves itself. If your cat becomes constipated, you may be able to help. Ask your vet about how to use a micro enema at home. At the first sign of constipation, this simple home intervention could prevent a larger problem from developing.
4
Let your cat rest. In order to recover, your cat will need to rest. Consider limiting your cat's activity level and making any necessary accommodations.^{[10]
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Research source} You may need to:
- Relocate food and water bowls
- Relocate litter boxes
- Limit playtime
- Limit your cat's contact with other pets
5
Attend any follow-up appointments. Depending on the severity of your cat's condition, as well any underlying causes, your veterinarian may want to schedule one or more follow-up appointments with your cat. In order to ensure that your cat is healing properly, it is important for you to attend these appointments.^{[11]
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Research source} The number of appointments (if any), as well as their frequency will vary based on a number of factors. These include:
- Your cat's age
- Other health problems present
- The underlying cause of megacolon in your cat (if any)
- The likelihood of reoccurrence