Constipation, the term to describe infrequent or difficult passing of faeces (poo), is an uncomfortable and unpleasant experience for our feline companions. There are various underlying reasons why a cat may become constipated, ranging from dietary issues to medical conditions and behavioural causes. Discovering the cause of your cat’s bowel issues is the first step towards overcoming the problem. 

What is constipation?

If your cat is not passing any bowel movements, or passing them very infrequently and with difficulty, they may be constipated. This tends to occur when the poo sits for too long in the large bowel. This is where water is absorbed from the digestive contents, and so the longer the faeces sit in the colon or rectum, the drier and harder they become, which just makes the problem worse. If the problem is not resolved, the poo can become impacted in the large bowel, which is known as obstipation.

Signs of constipation in cats

If your cat hasn’t passed a bowel movement for over 24 hours, they are likely constipated. Many cats like to toilet outside, however, so monitoring their poop can be tricky. Constipated cats often have some abdominal pain, which may present as them being tense, hunched over or curled up. They may not want to be stroked or cuddled. Their appetite may decrease. You may notice them straining to toilet, and this may be accompanied by vocalisation. Small, hard nuggets of faeces may be passed with effort. Sometimes, a small amount of liquid poo is passed, which can be misinterpreted as diarrhoea, when in fact it is just an overflow of faeces around the obstruction.

Why is my cat constipated?

There are a variety of reasons for constipation in cats. Here are the most common.

Litter tray problems

Cats can be very particular about where they toilet. If your cat uses a litter tray, they will probably have a strong preference for the location of the tray and the type of litter. If you have recently moved the tray, changed the litter, or not been cleaning the tray as often, this may put them off toileting, which can then lead to constipation. Litter box avoidance can also occur if there is competition from other cats in the household for the tray, or if something unpleasant has happened (such as a loud noise) while the cat was using the tray. 

Dehydration

If a cat isn’t drinking enough, or is dehydrated for some reason, the body will draw more water out from the faeces in the colon, leading to dry, hard stools which can become impacted. Certain medical conditions, such as chronic kidney disease, can be an underlying factor. 

Diet

Both too much and too little fibre in the food can contribute to constipation. Cats should be fed a diet which is nutritionally complete, and suitable for their age and lifestyle. 

Pain

Chronic conditions such as osteoarthritis can make it difficult and uncomfortable for cats to posture properly to pass faeces, leading to with-holding. They may also struggle to get into the litter tray. Pain externally around the anus, such as abscesses or anal gland impaction, or internally in the colon or rectum can also lead to difficulty in passing bowel movements. 

Hair ingestion

A common cause of constipation in long-haired cat breeds is hairballs. Hair can block the gastrointestinal tract, and make bowel movements bulkier and difficult to pass easily. 

Neurological problems

If the nerves which control bowel function are diseased or damaged, the ability to pass poo will be affected. This can present as incontinence, or can also cause retention of the faeces. Car accidents are a common source of trauma to cats. Urinary retention, paralysis of the hindlimbs or tail and other neurological signs can be seen alongside the faecal problems. 

Pelvic abnormalities

Injuries to the pelvis which cause an altered anatomy, or tumours, obstructions and strictures in the pelvic area can all cause the colon to become squashed. This constricts the flow of intestinal contents and causes a build-up of faecal matter behind the narrowed area. 

Medications

Some drugs can cause constipation as a side-effect. This is usually known beforehand, and so measures can be taken to ensure this doesn’t become a problem.

Megacolon

The colon can become distended (megacolon), leading to a reduced ability of the colon walls to contract, which is needed to push the faeces towards the rectum and out of the body. This can occur as a primary disease (idiopathic megacolon), where the colon muscles become progressively unable to contract. It can also be secondary to severe constipation, as the pressure of the built-up faeces causes the colon walls to stretch and become lax. 

What do I do if my cat is constipated?

If your cat hasn’t passed faeces in the last 24 hours, seems uncomfortable when trying to defecate or is passing small, hard faeces, speak to your vets. They may wish to examine your cat. Severe or recurrent episodes of constipation may warrant further investigations such as x-rays, blood tests or scans. 

There are some options to managing constipation in cats.

  • Maintain good hydration
  • Provide a suitable diet, such as a high fibre diet. Some cases of megacolon may do better on a low residue diet, so discuss any changes in food with your vet.
  • Litter tray management
  • Enemas
  • Laxative drugs
  • Pro-kinetic drugs – these encourage the passage of the gut contents through the system
  • Surgery – some cases of megacolon may benefit from surgical management.

Constipation in cats: final thoughts

Cats can get constipated for a variety of reasons, from diet and hydration to litter box behaviour and medical conditions. Signs vary, but they may seem distressed and painful when trying to defecate, struggle to pass faeces and may pass small, hard poops. Depending on the severity of the blockage, treatments include dietary and hydration management, enemas, laxatives and other medications. Constipation is an uncomfortable and unpleasant condition, and can quickly worsen, so seeking veterinary advice is recommended. 

Further Reading