Straining unproductively can be a symptom of either constipation or large intestinal diarrhoea. In either case, small amounts of mucous, gooey, or even blood-tinged stool can be passed and there is a lot of pushing involved. Difficulty urinating can also appear as straining. If you are unsure of the cause of straining, it is best to see a vet as soon as possible because urinary straining is an emergency and many home remedies for constipation can rapidly worsen the symptoms or even be toxic to your pet.  Note pets usually will pass a stool once daily but their large intestine has the ability to store up to a few weeks’ worth of stools so if you have not seen your pet pass a stool for 1-2 days, it might be worth waiting a little longer. This is particularly the case if you pet has had a recent anaesthetic, is on drugs that may block them up or haven’t eaten much in the preceeding few days.

Why do pets get constipated?

Simple constipation can be caused by any number of reasons. Some animals excessively groom themselves (especially if they are itchy) and find themselves passing stools containing large amounts of hair. This is not an uncommon cause for constipation and often treatment for the excessive grooming is helpful.

Pets may ingest foreign material such as gravel or stones that aren’t digestible and can become painful or even sharp to pass causing straining and discomfort. Cooked bones are a very common cause of this in dogs and can be very painful to pass.

Some medications can have constipation as a side effect (e.g. sucralfate or fluoxetine).

Some metabolic diseases such as kidney failure can lead to an electrolyte imbalance that causes dryer faeces and constipation. This is particularly relevant in older patients exhibiting constipation signs.

An internal obstruction may also be causing the problem. For example, animals hit by cars often suffer a fractured pelvis. These usually heal without surgery but can heal such that the pelvic canal through which stool must pass is narrowed. Constipation may not result for years after the initial trauma. An old fracture is generally obvious with a radiograph of the abdomen.

Prostate glands in male dogs can become enlarged later in life and press on the large bowel narrowing it. Desexing the dog usually solves this problem, though sometimes the problem is more serious, such as a prostate tumor. An enlarged prostate is often palpable rectally though the size of the prostate is better assessed with a radiograph.

Treatment for simple constipation

Simple isolated episodes of constipation are easily treated with a small inserted jelly-based enema in many cases.

A short course of medication may be prescribed. This might be stool softener such as Lactulose or it might be a medication to increase the normal motility (contractile strength) of the large intestine, such as Cisapride. Some patients may require long term therapy.

For all cases of constipation we will recommend an increase in water intake. This might be by providing wet food only diluted down with additional water. However for severe or dehydrated cases we may elect to hospitalize them on intravenous fluids to rehydrate them and ensure their faeces is as lubricated as possible.

We do not recommend the use of oils given orally as during the process of administration these are often inhaled accidentally leading to nasty inflammatory changes in the lungs.

In some cases changes to the diet may be recommended for example changing to a high fibre food or supplementing with additional fibre. In some cases a low residue, highly digestible food is of benefit to create a smaller stool.

Recurring constipation

In recurring constipation, the same treatment methods as listed above are employed but on a more long-term basis. Enemas may have to be used more frequently and medications/diet changes may represent permanent management methods. In most cases, medications used will need to be tweaked over time according to the pet’s response so be sure to report any changes or concerns to your vet.

Constipation Vs Obstipation

When constipation becomes a more permanent and continuous problem, it is more correct to use the term obstipation. Here, patients are unable to effectively or completely empty the colon on their own. The obstipated colon is dilated and packed with an enormous, rock-hard burden of feces. The patient is usually quite uncomfortable, with more frequent unproductive straining, lethargy, appetite loss, and even vomiting. Small hard bits of stool are often found around the house, yard as well as in the litter box. Sometimes liquid faecal secretions are passed around the hard faecal mass, leading the owner to incorrectly think the pet has diarrhea.

Usually the only way to relieve this is through a comprehensive enema performed under general anaesthetic. The patient must be hydrated (so often intravenous fluids are provided) so some patients may be hospitalized for 24-48 hours prior to the procedure to ensure the hard faecal mass is as hydrated/moist as possible. The enema involves inserting catheters filled with water or lubricant up the rectum to aid in pushing the faecal mass out and digital manipulation (both rectally and via abdominal manipulation) to break up the faecal mass. X-rays are often used to establish if any faeces is left and sometimes a second anaesthetic and enema is required in severe cases.

Subtotal Colectomy

A permanent resolution of this problem can be achieved by surgically removing the diseased colon. This generally eliminates the need for any stool softeners, pills, enemas etc. and the patient can resume a low maintenance lifestyle. The constipation is replaced by a looser consistency stool and, though sometimes this firms up into a more normal consistency stool after a couple of months, it is important for an owner expect this change to be permanent. Patients appear much more comfortable with this new arrangement and most owners are so satisfied with results as to wish they had pursued surgical treatment sooner.

However there are several important points to consider when electing to proceed with surgery:

• The colon has a very high population of bacteria so removing it causes a high intra-operative risk of bacterial contamination which can lead to peritonitis and potentially lethal complications. For this reason patients are watched very carefully post-operatively and any concerns should be communicated without delay.
• Specific diets are often recommended during the recovery period, usually something highly digestible to minimize the amount of stool produced. The 20% of cats who have persistent loose stool problems generally must stay on this diet permanently.
• It is not unusual for a patient to refuse food for several days after surgery. The patient must not be allowed to go without food for more than five days without some kind of nutritional support. This may require force feeding or feeding through a tube.
• Scarring of the surgery site (stricture) may lead to narrowing of the bowel and recurrence of the obstipation. If this occurs a second surgery would be necessary to remove the narrowed area.

Most cats do not experience complications with this surgery beyond the initial loose stool mentioned. Results are described as good to excellent.