Cat Constipation: Signs, Causes & Treatment

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7 min read

Updated - Oct 13th, 2022

Help! My cat is constipated…

My cat hasn’t pooped in 3 days!

While studying your cat’s litter box habits may not be on the top of your “to do” list, it should be. Believe it or not, you’ll want to be “all up in the know” about your cat’s bowel movements and digestive tract. That’s because it’s important to monitor how often your cat urinates or has bowel movements. In normal healthy cats, they should use the litter box typically 2-4 times per day, making up one poop and 2-3 normal-sized urinations (which are typically the size of a woman’s clenched fist). In full disclosure, I use an automatic kitty litter box and can track how many visits my cat makes to the litter box on an app.

If your cat’s defecation is every other day, then I’m worried about obstipation (which means severe or complete constipation, when no poop is coming out at all!)

So, what are clinical signs that my cat is constipated?

  • Straining to urinate or defecate in the litter box
  • Having bowl movement accidents outside of the litter box
  • Having firm, dry, small fecal balls in or around the litter box
  • Taking longer to defecate in the litter box or making multiple trips to the litter box
  • Vomiting
  • Reduced amount or lack of feces in the litter box for several days
  • Crying out in pain while defecating
  • Having fecal matter stuck to the fur on the rear end
  • Meowing more near the litter box
  • Decreased appetite
  • Weight loss
  • Dehydration

Now, keep in mind that normal healthy cats don’t typically become constipated. As a veterinarian, I see feline constipation more in the following:

  • Middle-aged to older cats (as they are more likely to have underlying health problems)
  • Obese cats (who can’t groom their hind end or perineal region)
  • Cats with osteoarthritis that may have pain jumping into the litter box (which then requires pain medication, a ramp and lower-walled litter boxes)
  • Cats with underlying medical problems

What are the common causes of constipation in cats?

  1. Metabolic disease that causes your cat to lose too much water (e.g., chronic kidney disease, hyperthyroidism, diabetes, etc.) and become dehydrated – which is why water intake is so important as your cat ages!
  2. Feline idiopathic megacolon (where the colon smooth muscle isn’t working well)
  3. Pelvis/bone or nerve problems (like having had some type of trauma like a pelvic fracture when your cat was younger) or strictures in the region
  4. Cancer
  5. Dietary Issues
  6. Pain from arthritis
  7. Inherited causes (more commonly seen in the Manx cat)
  8. Foreign bodies (e.g., something stuck in the intestines from massive hairballs to missing toys)

How does my cat get diagnosed?

Your veterinarian will diagnose your cat with constipation based on several things, including a thorough history (like what type of food you are feeding, what the water sources are, etc.), physical examination findings (like palpating a large amount of feces in the colon, feeling the kidney size, etc.), and a medical work up. A medical work up is important to find the possible cause of constipation in your cat and will consist of the following:

  • A minimum of blood work to check the kidney and liver function, salt balance, protein level, and blood sugar
  • A complete blood count to look at the white and red blood cell count
  • A thyroid value (if your cat is over 8-9 years of age)
  • A urine test is important to look at how well the kidneys are working (the more concentrated and yellow the urine being better)
  • X-rays will help look at the size of the pelvis opening, and look for any obvious cancer or physical causes for not being able to defecate
  • An abdominal ultrasound in reoccurring cases of constipation to help rule out cancer.

Once this veterinary diagnostic work up is done, the most important part of making your cat comfortable and treating their constipation is getting that backed up feces out of there! Please know that some cats may need long-term medication or dietary changes to prevent chronic constipation from happening again. This is important because we want to prevent megacolon, which is when the colon becomes chronically dilated and is difficult to treat long-term.

How do you treat my cat’s constipation?

1. Changing your cat’s food

Changing to a high fiber diet in the form of canned food (which provides more water) is important for the long-term management of constipation in cats. Ideally, this new food should be high in soluble fiber, which is important for increasing water into the stool, and is highly digestible/fermentable. With cat constipation, I prefer canned food; however, not all cats will eat that! If your cat only eats dry food, please know that there are high fiber, prescription dry cat foods too. Remember, when it comes to cats, diet changes should occur very slowly to allow them plenty of time to acclimate. Psyllium products (e.g., Metamucil™) can also be sprinkled onto food, but keep in mind that some cats won’t eat readily.

2. Fluid therapy

Whether given under the skin (subcutaneous or “SQ”) or in the vein directly (intravenous or “IV”), this is an important way of helping hydrate your cat and restore some moisture into the feces. This is also why it’s so important that your cat’s water intake is enhanced – by providing clean, fresh water at all times!

3. Stool softeners

There are several types of stool softeners used in cats. These can be over-the-counter (Miralax™) or prescription (e.g., lactulose). When in doubt, always check with a veterinarian first prior to using these as they can cause secondary side effects (like increased potassium levels or diarrhea).

  • Miralax™ (polyethylene glycol 3350): This can be picked up over the counter and mixed with a small amount of canned cat food. Check with your veterinarian first, but I generally use 1/8 to 1/2 a teaspoon every 12-24 hours orally as needed to treat cat constipation. This drug helps pull more water into the colon, but can cause changes in salt balance so must be used carefully.
  • Lactulose (A sticky, sweet veterinary prescription liquid medication to loosen the stool): This is a medication that you have to get from your veterinarian, and is a stool softener/laxative. I usually dose it at 1/2 – 3/4 of a tsp (2.5 – 3.75 mls) orally every 6-8-12 hours until the stool is looser. Use consistently for the next 3-5 days, then only as needed to make the stool soft. This is designed to pull water into the gastrointestinal tract. Unfortunately, it’s super sticky and hard to get cats to take it readily!

Pet Pro Tip: Any responsible pet owner should seriously consider pet insurance. Properly understanding how pet insurance works and what pet insurance covers can help you make an informed decision about your pet’s health needs and plan your finances accordingly!

4. Enemas

In constipated cats, the use of warm water enemas by your veterinarian will help loosen the bowel movements so your cat can defecate. Sometimes we’ll even put in a temporary feeding tube (e.g., nasogastric tube) into the stomach to pass polyethylene glycol 3350 in over 8-12 hours to help with defecation. Please know that you should never give enemas at home without consulting your veterinarian or the ASPCA Animal Poison Control Center. That’s because I’ve seen cats develop life-threatening signs from well-intentioned pet parents using certain types of Fleet enemas in their cat (Please leave enemas to your veterinarian and never administer these at home!).

5. Prokinetics

These are drugs that help the gastrointestinal tract contract more. These are prescription medications from your veterinarian such as cisapride (which is typically only available for veterinary professionals or compounding pharmacies), metoclopramide, and ranitidine. Cisapride is thought to be the most effective.

6. Deobstipation

In severe cases that aren’t responding to treatment, your cat may need to be anesthetized to manually remove the feces from the colon. Nobody likes this one.

7. Surgery

In rare cases of megacolon that have failed medical management, surgery for a colectomy can be considered but is generally not recommended except as a “last hope” type of procedure.

8. Lastly, euthanasia

Obviously, this is one that we don’t want unless the constipation is unmanageable. But some cases can be so severe and difficult to manage, that it becomes a chronic struggle. That’s one of the reasons why I’m also such an advocate for Pumpkin Pet Care, so costs don’t have to play a role in care.

9. Husbandry

Make sure that you’re keeping your cat’s litter boxes clean. The general rule is “n+1.” If you have 1 cat, you need two boxes. If you have 3 cats, you need 4 boxes. And yes, just because you have more boxes doesn’t mean you can clean less. Keep them clean every single day to make sure your cat is urinating and defecating normally. Again, litter boxes are a dirty business, but it’s so important to keep your cat’s box clean so you can catch those medical problems like constipation sooner than later!

When it comes to your cat’s litter box and overall health, it’s so important that you monitor their bowel movements and digestive tract to help keep your cat healthy.

Dr. Justine Lee

Veterinary Specialist in Emergency Care & Toxicology, Writer
Dr. Lee, DACVECC, DABT is a board-certified veterinary specialist in emergency care (DACVECC) & toxicology (DABT).
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