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A Guide To Constipation in Cats

Aimee Labbate
  • Aimee Labbate

  • RCVS: 700039


What is constipation in cats?

Constipation is fairly common in cats, although its causes and severity can vary widely. It is most common in middle-aged and older cats and is characterised by an abnormal accumulation of faeces in the colon (large intestine). This makes it more difficult for the cat to defecate, and they will go less often.

How does constipation in cats occur?

As the faeces sit in the colon more water is absorbed from them, causing them to become harder and even more difficult to pass. The cat will strain as they attempt to pass the stool and sometimes small amounts of liquid faeces are squeezed around the hard faecal mass - this can be confused with diarrhoea.

Why do cats get constipated?

Many factors can cause or contribute to the development of constipation, but the main ones are:

  • Dehydration
    • If a cat becomes dehydrated then they will absorb more water from the colon, potentially leading to constipation.
    • Chronic kidney disease (CKD) is common in older cats, and tends to cause mild dehydration, so this can be a common cause of constipation.
  • Pain
    • Arthritis can make it more painful and difficult for a cat to get into and out of their tray, and for them to adopt the squatting position to defecate.
    • This can make them reluctant to go, predisposing to constipation.
  • Environment and behaviour
    • Cats may be reluctant to defecate if the litter tray is dirty or if there is competition with other cats for use of the tray.
    • They may not like the type of litter used or the position of the tray if it is somewhere noisy and busy.
  • Previous pelvic injury e.g. pelvic fracture
    • This is a fairly common injury in cats that have been hit by a car. Sometimes, when the pelvis heals the opening through it can become narrowed, causing compression of the colon and making it more difficult for faeces to pass. This can lead to a build up of faeces behind the constriction and potentially very serious constipation.
    • The cat may then surer from secondary megacolon, where the colon becomes extremely distended with faeces, and the muscle wall can no longer contract due to the degree of stretching. Surgery is usually then needed to remove this section of affected bowl.
    • Narrowing of the pelvis may also occur due to other reasons e.g. a tumour or stricture.
  • Neurological problems
    • Problems with the nerves that supply the colon can result from injuries such as road traffic accidents and ‘tail-pull’ injuries affecting the lower spine. These disturbances to the nerve signals can sometimes result in the cat being unable to defecate or urinate.
  • Idiopathic megacolon
    • In this condition there is a problem with the muscle wall of the colon, leading to it not being able to contract properly. This results in constipation that becomes extreme with the cat eventually being completely unable to pass faeces (obstipation).
    • The treatment is surgery to remove the affected portion of colon.
    • The cause of the condition is unknown.

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What are the signs of constipation in cats?

Signs of constipation are usually fairly easy to identify and include:

  • Straining to pass faeces
  • Pain when passing faeces
  • Stools are dry and hard
  • Reduced frequency of defecation
  • Small amounts of diarrhoea are sometimes passed as this squeezes around the hard faecal mass when the cat strains to defecate

How is constipation in cats diagnosed?

While constipation is usually easy to diagnose based on the clinical history and physical examination, the vet will normally then suggest a number of tests to investigate the cause. For example, they would normally recommend blood and urine tests (e.g. to check for kidney disease) and possibly x-rays, ultrasound or endoscopy.

How is constipation in cats treated?

Treatment will always depend on the underlying cause as well as the duration and severity of the constipation. If the constipation is mild, it is usually relatively easy to manage but in more severe cases the cat may need to be hospitalised for intravenous fluids and an enema under general anaesthetic.

The long term treatment options for constipation are as follows:

  • Maintain hydration (this is especially important where the cat is prone to dehydration, as with CKD for example)
    • Feeding wet food rather than dry food can help.
    • Try to increase the amount of water that your cat drinks – a water fountain can sometimes help. These are available in our shop by following this link.
  • Dietary management
    • Increasing the water content can help, so switching to wet food is usually recommended.
    • Increasing the fibre content can also help to produce softer stools more regularly.
    • In very severe cases (with megacolon for example) the vet may recommend feeding a low residue diet to reduce the amount of faeces that are produced.
  • Litter tray management
    • Increasing the number of litter trays can give your cat more choice, in case they are fussy as to where they go.
    • Making sure it’s easy for your cat to get into and out of the litter tray is especially important for older arthritic cats.
    • Ensure you change the litter regularly so the tray is nice and clean.
  • Laxatives
    • There are many different types of laxatives available that may help with the constipation. These work in slightly different ways, by lubricating the colon or drawing water into the faeces, for instance.
    • Please discuss with your vet which is most appropriate for your cat.
  • Enemas
    • Your cat may need intermittent enemas to relieve constipation.
    • A ‘mini-enema’ can be done in a conscious cat and can help with mild constipation.
    • For more severe cases your cat may need a general anaesthetic for a full enema.
  • Medication
    • Some drugs help to increase the motility of the colon and can be particularly helpful alongside other treatments such as diet and laxatives.
  • Surgery
    • If medical management is not sufficient to control the constipation and in severe cases (e.g. megacolon) surgery may be recommended. This involves removing a portion of the large intestine – while it is major surgery and complications are possible, many cats do well after surgery and the results can be very good.

What is the prognosis for cats with constipation?

This varies greatly between individual cats depending on the cause and severity of the constipation. Mild cases can usually be managed well but more severe cases can be difficult to treat and may ultimately need surgery.

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