Constipation

About constipation

Constipation is medically defined by the passing of infrequent bowel motions (stools), fewer than 3 per week. However, people may also experience the passage of hard or dry stools as constipation.

Occasional constipation is extremely common and may follow a change in routine (such as travel), a change in diet, a brief illness such as a respiratory infection, or medications such as antibiotics or analgesics.

Chronic constipation, present for more than a few weeks, is rarely due to a life-threatening condition. However, if it does not respond to simple measures, see your doctor.

Stools explained

Food nutrients are absorbed in the small intestine.

Waste is massaged down the length of the large intestine by waves of muscular contractions (peristalsis). Once the excess water is removed, the waste is temporarily stored in the rectum. The anus is a muscular ring (sphincter) that can be opened at will to allow the removal of faeces.

Water makes up about three-quarters of faecal content, while the rest is composed of solids, including undigested fibre, intestinal bacteria and dietary fats.

Symptoms of constipation

The symptoms of constipation include:

• needing to open the bowels less often than usual
• hard, dry stools that may be painful to pass
• straining to pass the motion
• having to sit on the toilet for much longer than usual
• the sensation afterwards that the bowel hasn’t fully emptied
• bloated abdomen
• abdominal cramps.

In some cases, constipation is caused by more serious illnesses and events, including tumours and systemic diseases.

Lifestyle-related causes of constipation

Constipation can be caused by many different lifestyle factors that often work in combination, including:

• A change in routine – normal bowel motions depend on the regular and rhythmic contraction of the bowels. This is part of the body’s internal ‘clock’ and is often upset with changes in routine. This type of constipation is often seen in shift workers and travellers.
• Low-fibre diet – as fibre is indigestible, it adds bulk to the faeces, making it more easily pushed along the digestive tract. There are 2 broad types of fibre; soluble and insoluble. Soluble fibre helps to soften the faeces. Good sources of soluble fibre include legumes, fruits and vegetables. Insoluble fibre adds bulk to the faeces, helping it to move more quickly through the bowel. Good sources of insoluble fibre are in wheat bran, wholegrain breads and cereals.
• Insufficient water – the fibre in faeces will only plump up with water. Constipation can occur from a high-fibre diet if insufficient water is consumed.
• Lack of regular exercise – living a sedentary lifestyle or being restricted in movement due to a disability are common causes of constipation.
• A tendency to ‘put off’ going to the toilet – ignoring the urge to go means that more water will be extracted from the stools, making them difficult to pass. Regularly ignoring this urge may make the body less sensitive to normal signals to go to the toilet.
• Some medications – such as narcotics (particularly codeine), antidepressants, iron supplements, calcium-channel blockers (antihypertensives, particularly verapamil) and non-magnesium antacids are known to slow bowel movements.
• Pregnancy – the action of hormones, reduced activity and the pressure of the growing uterus against the intestines mean that constipation is common during pregnancy.
• Advancing age – constipation is more common in the elderly. This is due to a number of factors, including reduced intestinal muscle contractions and reliance on regular medications.
• Illness – a period of illness, particularly an illness resulting in hospitalisation and bed-rest, typically results in constipation. Factors include change in routine, shyness, reduced food intake, pain (especially after abdominal surgery), and pain-relief medication such as morphine. Short-term treatment with laxatives is often required.

Medical causes of constipation

Constipation is sometimes symptomatic of underlying medical problems, such as:

• Disordered defecation – this condition is an important cause of chronic constipation and is caused by insufficient forward contractions of the lower bowel (anorectum), or by increased resistance in the lower bowel. Straining is a very common symptom and individuals with disordered defecation may need to push on or trigger the anal canal to generate defecation.
• Slow transit – some people naturally pass motions less often than most people. It seems their bowel ‘pacemaker’ may be less active. These individuals are more likely to become constipated with minor changes in their routine.
• Irritable bowel syndrome – characterised by abdominal pain, bloating, and either constipation or diarrhoea or alternating constipation and diarrhoea. People with irritable bowel syndrome may have features of slow transit, disordered defecation, or both.
• Anal fissure – a tear in the lining of the anus (anal mucosa). The person may resist going to the toilet for fear of pain.
• Obstruction – the rectum or anus may be partially obstructed by, for example, haemorrhoids (piles) or a rectal prolapse.
• Rectocele – the rectum pushes through the weakened rear wall of the vagina when the woman bears down or strains.
• Hernia – an abdominal hernia can reduce intra-abdominal pressure, which makes it more difficult to pass a motion.
• Abdominal or gynaecological surgery – a combination of change in routine, strange surroundings, post-operative pain and codeine-containing analgesics is a potent cause of constipation and often needs preventive care.
• Problems of the endocrine system – such as hypothyroidism, diabetes or hypopituitarism.
• Tumour – pain while trying to pass a stool could be a symptom of rectal cancer.
• Diseases of the central nervous system – such as multiple sclerosis, Parkinson’s disease or stroke are associated with an increased susceptibility to constipation.

Complications of chronic constipation

Some of the complications of chronic constipation include:

• Faecal impaction – the lower bowel and rectum become so packed with faeces that the muscles of the bowels can’t push any of it out.
• Stercoral ulcer – the presence of impacted stool can erode the lining of the lower bowel. These ulcers can cause significant bleeding or bowel perforation.
• Faecal incontinence – an overfull bowel can result in involuntary ‘dribbling’ of diarrhoea.
• Haemorrhoids – constant straining to open the bowel can damage the blood vessels of the rectum.
• Rectal prolapse – the constant straining pushes a section of rectal lining out of the anus.
• Urinary incontinence – the constant straining weakens pelvic floor muscles. This makes the involuntary passing of urine more likely, especially when coughing, laughing or sneezing.

Diagnosis of constipation

The underlying reason for the constipation must be found. Diagnosis may include:

• a careful medical history, to determine the type of disorder
• detailed questioning about medications, diet, exercise and lifestyle habits
• physical examination, including an examination of the anal canal and rectum
• a trial of simple laxatives is usually done, as the outcome of this helps with accurate diagnosis of the cause
• referral to a specialist in disorders of defecation, who may perform simple tests of anorectal function, or anorectal manometry (pressure measurements of the rectum and anus)
• colonoscopy in those with alarm symptoms or aged over 50 with new onset of constipation.

Treatment for constipation

Treatment depends on the cause, but could include:

• Stopping or changing medications – that can cause constipation.
• Removal of the impacted faeces – which may involve enemas, stool softeners and a short-term course of laxatives.
• Dietary changes – such as increasing the amount of fibre in the daily diet. Dietitians generally recommend about 30g of fibre every day. Good sources of fibre include wholegrain cereals, fruits, vegetables and legumes. The intake of foods such as milk, cheese, white rice, white flour and red meat should be restricted, because they tend to contribute to constipation.
• More fluids – liquids help to plump out faeces. However, it is important to restrict the intake of diuretic drinks such as tea, coffee and alcohol.
• Fibre supplements – these may be helpful if the person is reluctant or unable to include more wholegrain foods, fresh fruits or vegetables in their daily diet. As fibre supplements can aggravate or cause constipation, always check with your doctor or dietitian when using them.
• Exercise – one of the many benefits of regular exercise is improved bowel motility. Ideally, exercise should be taken every day for about 30 minutes. People with a condition that affects mobility need to be as active as possible each day, as every little bit of regular exercise helps.
• Treatment for underlying disorder – such as surgery to repair an abdominal hernia, hormone replacement therapy for hypothyroidism, or anaesthetic cream and sitz (salt water) baths for an anal fissure.
• Laxatives – there are 2 main types: bulk forming and osmotic agents that increase the water content of the stool. Agents that increase the water content may interfere with the absorption of water from the bowel, or swell or bulk up the stool with fluid. Chronic constipation that has not responded to a trial of fibre supplementation can be safely treated long term with laxatives and avoid further medical interventions. There is little evidence that chronic use of laxatives at appropriate doses will lead to a ‘lazy’ or ‘twisted’ bowel.

Disordered defecation not responding promptly to fibre supplementation and laxative use may require use of suppositories or enemas and pelvic floor 'retraining’ by biofeedback therapy, which is offered by centres specialising in anorectal disorders.

Slow transit constipation that has not responded to simple laxatives may be treated with medications that increase the speed of stool transit.

Where to get help

• Your GP (doctor)
• Pharmacist

Need treatment today?

Need treatment today, but it's not life-threatening and you can't get a GP appointment, there are services available:

• Urgent Care Clinics – provide care for conditions that require treatment today but not an emergency response (extended hours)
• Nurse-on-Call Tel. 1300 60 60 24 – for expert health information and advice (24 hours, 7 days)

Emergency care

• In an emergency, always call triple zero (000)
• Emergency department of your nearest hospital

More information

• Dietitians Australia Tel. 1800 812 942