Chronic constipation

What counts as constipation

There is no daily quota. healthdirect describes the normal range as anywhere from three bowel motions a day to one every three days. Going less often than someone else is not a medical problem.

What counts is the experience rather than the number. Constipation means stools that are hard or lumpy, straining to pass them, a feeling that the bowel has not emptied, needing to help things along or going less often than is normal for you. When that has been going on for months it is chronic constipation, and it is worth a proper look rather than another packet from the chemist.

Two things make a consultation about this far more useful than it would otherwise be. The first is the Bristol Stool Chart, a simple picture scale from one to seven that describes stool consistency. Saying "mostly type one or two" carries more information than saying "constipated". The second is keeping a diary for a fortnight. People are poor at estimating how often they actually go, and the diary regularly turns out to tell a different story from the memory of it. Recording straining, incomplete emptying and whether anything had to be done by hand matters as much as the count.

The other thing that matters is change. Constipation that has been there since childhood is a different proposition from constipation that started six months ago in someone over 45.

Why it happens

• Diet and fluid. Too little fibre, too little water and long gaps between meals.
• Not enough movement. Long periods of inactivity, bed rest or illness slow the bowel down.
• Ignoring the urge. Common in shift workers, teachers, nurses and anyone who cannot leave the room. Repeatedly overriding the signal makes it quieter.
• Medicines. Opioid painkillers are the worst offenders. Iron tablets, some antidepressants, some blood pressure medicines and some antacids all contribute.
• Other conditions. An underactive thyroid, diabetes, Parkinson's disease and disturbances of potassium or calcium.
• Irritable bowel syndrome with constipation, where pain is part of the picture. There is more on the irritable bowel syndrome page.
• Pregnancy, and the weeks after childbirth.
• A blockage, which is uncommon and is the reason new constipation in an older adult is taken seriously.

The three patterns, and why the difference matters

Chronic constipation is not one problem. Sorting out which pattern is present is the single most useful thing an assessment does, because the treatments are not interchangeable.

• Normal transit constipation is the commonest. The bowel moves at a normal speed but the stool is hard and passing it is difficult. Fibre, fluid, routine and the right laxative usually work.
• Slow transit constipation means the bowel itself moves slowly, so there is little urge at all and days pass. It needs more than dietary change and is managed with a planned laxative regimen.
• Outlet or pelvic floor problems, properly called a defecatory disorder or dyssynergic defecation, occur when the muscles that should relax to let stool out tighten instead. The stool can be soft and still be difficult to pass. The clue is straining, digital assistance and a feeling of blockage at the bottom. Laxatives alone do not fix this, because the problem is not the stool. The treatment is retraining with a pelvic floor physiotherapist, usually with biofeedback, and it works well.

That last group is the one most often missed, and the one where people have usually tried everything on the pharmacy shelf before anyone asks the right question.

The three do not sit in separate boxes. Around two-thirds of people with a pelvic floor problem also have a slow-moving colon, and in that group retraining the outlet often speeds the transit up as well, because a bowel that cannot empty properly backs up. This is the main reason the outlet is worth checking first rather than last.

A smaller number have a structural reason rather than a functional one, such as a rectocele, a prolapse or the bowel telescoping into itself. These are found on examination and on the tests below, and they are managed differently again.

When it needs investigating

Most chronic constipation does not need a colonoscopy. It is recommended when something in the picture suggests more than a sluggish bowel:

• constipation that is new and unexplained, particularly over the age of 45
• rectal bleeding or iron deficiency anaemia
• unintended weight loss
• new obstructive symptoms such as bloating, distension or pain when passing stool
• rectal pain or a constant feeling of needing to go
• a change in the calibre of the stool that persists
• a family history of bowel cancer or inflammatory bowel disease
• symptoms that do not respond to sensible treatment

Blood tests check the thyroid, calcium, glucose and iron, because a handful of treatable conditions present this way.

The examination that decides the rest

A careful rectal examination is the single most informative part of the assessment, because it is where a pelvic floor problem shows itself. The person is asked to bear down as though opening their bowels. Normally the muscles relax and the pelvic floor descends. In a defecatory disorder they tighten instead.

The examination raises the question rather than settling it, and that distinction matters. A defecatory disorder is one of the most frequently missed causes of long-standing constipation, and impression alone is not enough to confirm or exclude it. Where the history or the examination points that way, the diagnosis is established objectively: anorectal manometry with a balloon expulsion test to measure what the muscles actually do, and an assessment by a pelvic floor physiotherapist of how the pelvic floor behaves during emptying. Those two together are what turn a suspicion into a diagnosis, and they are also what direct the treatment, because the answer for this group is retraining rather than more laxatives.

The specialist tests, when they are needed

These are for constipation that has not responded to sensible treatment, and they are the tests that tell the three patterns apart.

• Anorectal manometry with a balloon expulsion test. A fine catheter measures the pressures in the anal canal and rectum at rest and while pushing. A small balloon filled with warm water is then placed in the rectum and the person is asked to pass it. Most healthy people expel it within a minute. Being unable to, or tightening rather than relaxing while trying, is the objective evidence of a defecatory disorder. This is the only accurate test for it, and a normal result largely rules the problem out.
• A colonic transit study. A capsule of small markers that show up on x-ray is swallowed, and a single film is taken on day six. More than five markers still in the colon indicates slow transit. It is straightforward, widely available and inexpensive.
• Defecography. An imaging study of the act of emptying, used when manometry is inconclusive or when a structural problem such as a rectocele or an internal prolapse is suspected. It can be done with x-ray or, where available, with MRI.

The order matters. Marker retention on a transit study can be caused by an outlet problem rather than a slow colon, so a pelvic floor cause is sorted out first. Getting that sequence the wrong way round is how people end up labelled with slow transit constipation and treated for years with laxatives that were never going to be the answer.

What actually helps

Before medication

• Fibre, adjusted by type and built up slowly. Soluble fibre such as psyllium, oats and linseed softens stool and is generally better tolerated than large amounts of bran, which can increase bloating. healthdirect suggests 25 to 30 grams of fibre a day for adults. The practical method is to add about 5 grams a day in the first week and another 3 to 5 grams each week after that. Going from very little to a great deal in a week is the commonest reason people conclude that fibre does not agree with them. Give it several weeks before judging it.
• Fibre is not for everyone. It often makes slow transit constipation worse, and it does nothing for a pelvic floor problem. If symptoms are very long-standing and the bowel opens fewer than twice a week, more fibre is usually the wrong lever.
• Fluid, aiming for at least 1.5 litres a day. Drinking more water does not by itself cure constipation, but fibre without enough fluid reliably makes things worse. Mineral water with a high magnesium content has done better than low-mineral water in trials.
• Kiwifruit and prunes. A 2023 systematic review found fruit performed at least as well as psyllium for constipation, with kiwifruit producing more bowel motions a week than psyllium did and prunes matching it. Two to three kiwifruit a day is the dose that has been studied. Rye bread also beat white bread.
• Coffee. Caffeinated coffee stimulates the colon. One or two cups in the morning is a reasonable thing to build a routine around.
• Timing. Colonic activity peaks in the couple of hours after waking and again after meals. Using that window unhurried, at the same time each day, is more effective than most things in this list. Opening the bowels is partly a conditioned reflex and it can be retrained.
• Not ignoring the urge, which sounds obvious and is the habit that most often needs rebuilding.
• Position. A small footstool that raises the knees above the hips straightens the angle at the bottom of the rectum and makes emptying easier. It costs almost nothing and it helps a surprising number of people.
• Exercise. Worth doing, though the evidence here is weaker than it is usually presented. The trials have used quite different amounts, from half an hour of brisk walking a day up to an hour, over about three months, and the results have been mixed. Regular moderate activity is the common thread rather than any particular dose.

Laxatives

Laxatives are not a failure and they are not a last resort. The classes work differently, and healthdirect notes they take anywhere from 6 to 72 hours depending on the type.

• Bulking agents add soluble fibre and suit normal transit constipation. Psyllium, commonly known as Metamucil, and sterculia, commonly known as Normacol, are the usual ones.
• Osmotic laxatives hold water in the stool. Macrogol 3350, commonly known as Movicol or OsmoLax and written as polyethylene glycol or PEG in overseas guidelines, carries the strongest recommendation of any over-the-counter option in the joint 2023 American guideline, and it is suitable for regular, long-term use. Lactulose, commonly known as Actilax or Duphalac, and the magnesium-based products also work and are recommended more weakly.
• Stimulant laxatives prompt the bowel to contract. Senna, commonly known as Senokot, and bisacodyl, commonly known as Dulcolax, are the usual ones. Both are available without a prescription and they are useful for breaking a cycle and for slow transit.
• Docusate, commonly known as Coloxyl, is the surfactant softener sold as small capsules, and it has the weakest evidence of the group. In a head-to-head trial it did worse than psyllium. It still has a place, mainly for people who cannot manage a macrogol powder because of the taste or the volume of liquid it has to be dissolved in, and it is a sensible second choice for that reason rather than a first one.
• Suppositories and enemas, such as glycerol suppositories and the small Microlax enemas, work at the bottom end rather than through the whole bowel, which makes them particularly useful where the problem is emptying rather than transit.
• Prescription medicines are available when the above are not enough. They work by drawing fluid into the bowel or by speeding it up. They are not first-line, and they need a prescription and a conversation.

The fear of becoming dependent on laxatives is widespread. The older belief that stimulant laxatives damage the bowel and make it stop working has not held up, and the practical risk for most people is undertreatment rather than overtreatment. Long-term use is discussed and planned rather than improvised.

For pelvic floor problems

Pelvic floor physiotherapy, with biofeedback where available, retrains the muscles to relax at the right moment. An instrument in the anal canal shows the person what their own muscles are doing while they try to pass a balloon, and over several sessions they learn to reverse the pattern. It is painless and there is nothing to take.

Randomised trials have found it more effective than laxatives in people with a defecatory disorder, and the benefit is specific: it helps those with the outlet problem and not those with pure slow transit. A trial of glycerol or similar suppositories is often used alongside it. For this group it is the treatment that works, and no amount of laxative substitutes for it.

When nothing is working

Constipation that has not responded to treatment is not a reason to keep adding laxatives. It is a reason to go back to the start, because the usual explanation is that the pattern was never established in the first place.

1. Confirm the diagnosis. Has a pelvic floor cause been excluded with anorectal manometry and a balloon expulsion test, rather than assumed? This is where the answer most often turns out to have been sitting.
2. Check the treatment was properly tried. The right class at an adequate dose for long enough. A softener taken intermittently for two years is not a failed trial of laxatives.
3. Review the medicine list again, including anything started since the constipation did.
4. Check for impaction. Loose stool leaking around a hard, impacted mass is commonly mistaken for diarrhoea, and treating it as diarrhoea makes it worse.
5. Consider whether this is really irritable bowel syndrome. Where abdominal pain is prominent rather than occasional, the condition and its treatment are different.

Where all of that has been done and symptoms remain severe, prescription medicines that draw fluid into the bowel or speed it up are the next step.

Surgery is rare. Removing most of the colon helps a very small, carefully selected group, and where pain and bloating dominate it tends not to help and can make things worse. The decision belongs to a multidisciplinary team rather than a single consultation, and because it cannot be undone, a second opinion is worth having first. Constipation surgery was once offered as a quick fix. It is not one.

Where chronic constipation is assessed in Sydney

A/Prof Viraj Kariyawasam is a consultant gastroenterologist and hepatologist. Constipation that has not responded to the usual measures is assessed at consultation in Norwest, Rouse Hill, Pennant Hills and Macquarie Park.

Where a colonoscopy is needed, it is performed at Norwest Private Hospital, Macquarie University Hospital and Pennant Hills Day Surgery. A referral from your GP is needed for a consultation.