Constipation is a symptom rather than a disease. It occurs when the colon reabsorbs too much water, or if the muscles in the colon are contracting slowly or poorly so that the stool moves too slowly and loses too much water.
Constipation means different things to different people. Many people believe that not passing stools daily is constipation. This isn’t true. If your stools are soft and pass easily, you’re not constipated.
However, many people experience mental distress when they don’t pass stools daily.
True constipation occurs when stools become hard and difficult to pass, and there’s a feeling of incomplete emptying after a bowel movement. Almost everyone has constipation at some point. Fortunately, it’s usually not serious.
The normal number of bowel movements differs from one person to the next. Some people have bowel movements three times a day, while others have them only once or twice a week. Going longer than three or more days without a bowel movement is usually too long.
After three days, the faeces become harder and more difficult to pass.
Constipation can also alternate with diarrhoea. This generally occurs as part of irritable bowel syndrome (IBS). Faecal impaction is seen at the extreme end of the spectrum. This is when the stool hardens in the rectum and becomes lodged.
Occasionally, liquid diarrhoea may occur even with the obstruction due to colonic fluid leaking around the impacted stool.
Acute vs. chronic constipation
1) Acute (recent onset) constipation. This may be due to a serious medical illness where constipation is the underlying cause (e.g. colon tumours). Acute constipation requires an immediate assessment if it’s accompanied by symptoms such as rectal bleeding, abdominal pain and cramps, nausea, vomiting and involuntary loss of weight.
2) Chronic (long duration) constipation. This can cause significant pain and discomfort and affect quality of life.
Types of constipation
1) Diet and medication controlled constipation. Movement of the stools through the gut is normal and the muscles of the pelvic floor move properly. This type of constipation usually responds to fibre or laxative treatment.
2) Dyssynergic constipation. The muscles of the pelvic floor don’t work properly and may even perform the opposite function of what they’re supposed to do. The muscles are also often in spasm. These individuals usually complain of not being able to fully empty their bowels. It can also occur due to an outlet obstruction (such as a hernia). Dyssynergic defecation affects about a quarter or more of people with chronic constipation.
3) Slow transit constipation. The colon moves slowly and, as a result, bowels move very infrequently (sometimes only once every 2-3 weeks).
4) Combined dyssynergic and slow transit constipation.
Infants and children
As with adults, the frequency of children's bowel movements varies from child to child. Newborn babies can pass loose, runny stools a couple of times a day or only once a week. Breastfed babies may have frequent stools and may even have a stool with every feed.
As babies grow older, the number of daily bowel movements usually decreases, while the size of the stools increases.
It’s important for parents to realise that there are many "normal" patterns for bowel movements in children. Sometimes children's faeces turn red and they appear to strain to pass a stool, but if the stool is soft and the child has no other problems, this isn’t a concern.
Most children will occasionally become constipated. Usually this is only a short-term problem requiring home treatment. However, some children are frequently constipated (chronic constipation).
Symptoms of constipation
Reviewed by Kim Hofmann, registered dietitian, BSc Medical (Honours) Nutrition and Dietetics, BSc (Honours) Psychology, December 2017.