Skip to content

Why is my cat constipated?

Does your cat seem to be struggling to go to the toilet? Are their faeces very hard, or passed at infrequent intervals? If so, you’re not alone - constipation is a fairly common problem in cats, especially long-haired and older pets.

Informative image: cat litter tray

What is constipation?

Constipation is defined as a situation where a cat passes faeces either more infrequently than usual; struggles to pass faeces; passes faeces that are harder and drier than usual; or doesn’t pass faeces at all.

What are the symptoms?

As you would expect - a reduced frequency of defecation! Other common signs include straining to pass faeces (faecal tenesmus), often combined with pain when defecating (dyschezia). Often, the faeces that are passed are small, hard and dry - this is because they have spent so long in the colon that more water has been drawn out of them than usual. Occasionally, there may be passage of watery liquid material - this is due to irritation of the bowel walls. In severe cases, cats often lose their appetite and may even vomit as the food “backs up” all the way along their intestine.

Is there anything else it could be?

First of all, make sure the cat is able to urinate! A blocked bladder can look very similar (painful straining to go to the toilet), but is a medical emergency, requiring urgent veterinary treatment.

The other condition to rule out is diarrhoea, which may also present with straining and mucoid material - if in any doubt, though, bring your cat in for us to check over.

What causes constipation?

There are a wide range of different possible causes - as constipation is a symptom, not a single disease! The more common causes include:

●     Behavioural issues. Cats are fastidious creatures, and if they don’t like their litter tray, they won’t use it! If they don’t go to the toilet regularly, the faeces being held in their large intestine will get progressively drier and drier, until they cannot pass them easily (or even at all). This is one of the commonest causes of mild and intermittent constipation, and may be triggered by:

○     A dirty litter tray, for example, one that isn’t cleaned often enough.

○     Not enough litter trays - there should be a minimum of one litter tray per cat in the household plus one extra.

○     They don’t like the particular type of litter that’s being used.

○     If the litter tray is in a place they don’t feel comfortable - for example, many cats prefer to go to the toilet in concealed, out of the way places, so a litter tray in the open, or in the middle of a room, won’t feel comfortable for them!

●     Hairballs. This is probably the commonest cause of chronic, or ongoing, and recurrent constipation. This is most common in long-haired cats, but can occasionally occur in short haired breeds too. Cats groom themselves by licking; each time, they transfer some of that hair into their mouths and swallow it. In most cases, this doesn’t cause a problem; sometimes it forms a large ball that is vomited out; sometimes it forms an internal hairball (called a bezoar) and blocks the intestine; but most often it forms a large mat of hair and faecal matter in the colon which is really hard for the cat to push out.

●     Pain or discomfort. This is especially an issue in older cats with arthritis. Because it is painful for the cat to squat and defecate, they don’t do so until they really have to - driving the constipation to get progressively worse. Of course, the same applies to many other painful conditions affecting the hindquarters, like bites or abscesses around the anus.

●     Dehydration. The cat’s large intestine is really important in water balance, reabsorbing water from the faeces before they are passed. If the cat is dehydrated (for example, a cat with chronic kidney failure), the intestine absorbs more water to try and make up the shortfall, resulting in dry, hard, difficult to pass faeces.

●     Nerve or spinal damage. If the nerves that supply the colon and rectum are damaged or cut; or the part of the spine that control them is damaged (for example, following a road traffic accident or a spinal injury), this will impact on the cat’s ability to defecate. Some cats will develop incontinence, but others will instead end up with faecal retention and constipation.

●     Physical blockage. This is most common after a fracture of the pelvis. The cat’s pelvic canal is pretty narrow anyway; if the pelvis is injured in such a way as to make it even narrower, this may cause constipation.

●     Megacolon. This is a disorder where the muscles in the colon wall become stretched, baggy and ineffective. It can be Acquired (often due to chronic and long-lasting constipation), or Idiopathic (where it just stops working for no known reason). This big saggy baggy colon is unable to push the faeces out, resulting in constipation.

What can be done about it?

It depends on the severity and cause! In many cases, a simple laxative (such as a micro-laxative enema) is enough to get the gut moving again and solve the problem, at least in the short term. In more severe cases, it may be necessary to admit the cat to the hospital, super-hydrate them with intravenous fluids through a drip, and then manually unblock them under general anaesthesia (we usually use a soapy water enema - it’s a very time consuming and messy process, but it is usually very effective!).

Of course, if at all possible we’ll try to resolve the underlying problem. This may involve managing the number, position and hygiene of the litter trays; grooming the cat to remove excess hair; using pain relief to manage pain from arthritis; or surgically repairing a fractured pelvis.

In ongoing cases, or cats who are particularly prone to constipation, there are a number of techniques we, and you, can use to encourage healthy faeces and minimise the risk of an episode of constipation. Such methods include:

●     Maintaining hydration by feeding a wet food (tins or pouches) and encouraging drinking (for example, by using a cat water fountain).

●     Altering the diet - there are high-fibre diets for cats that may help in some cases; if hairballs are the problem, an anti-hairball diet may be useful.

●     Laxative medications such as liquid paraffin or lactulose are often very useful, if used judiciously. They work to soften the stool and lubricate it to encourage movement.

●     Prokinetic medicines work differently, to encourage stronger contractions of the gut wall. The most common drugs used are cisapride and ranitidine.

Sometimes, chronic constipation results in a Megacolon; if these control measures are insufficient, there are surgical options available - a subtotal colectomy to remove the bulk of the colon and plumb the healthy end into the rectum. This is a major procedure and inevitably results in diarrhoea (at least initially), but does resolve the underlying problem in most cases.

If your cat is constipated, please make an appointment for one of our vets to see them - there’s lots we can do to help!