Constipation in adults

For children, see the separate Constipation in children article.

Constipation in adults

Chronic constipation is common with a reported prevalence of 12-15% worldwide.¹²Different studies suggest that it is more common in the US and Europe than Asia²and conversely that it is more common in Asia and the Americas than in Europe.¹ There is a higher prevalence in women and it increases in prevalence with age.¹Non-white people report constipation more frequently than white people.¹ It is also more common in those of lower socio-economic status, residents of nursing homes and those with other medical conditions.³

What is constipation?⁴

Constipation is a symptom not a diagnosis and means different things to different people.

There is an internationally recognised medical definition of constipation which has been updated over the last few decades and, at the time of writing, involves the Rome IV criteria.

These state that a patient must have experienced at least two of the following symptoms over the preceding 3 months:⁵

• Fewer than three spontaneous bowel movements per week.

• Straining for more than 25% of defecation attempts.

• Lumpy or hard stools for at least 25% of defecation attempts.

• Sensation of anorectal obstruction or blockage for at least 25% of defecation attempts.

• Sensation of incomplete defecation for at least 25% of defecation attempts.

• Manual manoeuvring required to defecate for at least 25% of defecation attempts.

The Rome IV criteria also stipulate that a patient should not meet the suggested criteria for irritable bowel syndrome (IBS) and that loose stools are rarely present without the use of laxatives.

However, patients' use of the word may involve various symptoms and it is essential to ask patients exactly what they mean by the term constipation.

Patients may mean that:

• Faeces are too hard.

• They do not defecate often enough for 'inner cleanliness'.

• Defecation hurts.

• They have diarrhoea.

In the elderly, consider constipation in any patient presenting with:

• Confusion or delirium, functional decline.

• Nausea or loss of appetite.

• Overflow diarrhoea.

• Urinary retention.

Faecal loading or impaction should be suspected when there is a history of:

• Hard, lumpy stools, which may be large and infrequent (for example, passed every 7-10 days), or small and relatively frequent (for example, passed every 2-3 days).

• A need to use manual methods of faecal extraction.

• Overflow faecal incontinence, loose stool, excessive wiping, or regularly soiled underwear.

Causes of constipation in adults

Taking a careful history helps to determine the possible cause.

History:

• Always consider the possibility of a serious underlying cause. Particularly enquire whether there are associated 'red flags' such as weight loss or rectal bleeding.

• Frequency, nature, and consistency of the stool.

• Whether there is blood or mucus in/on the stools.

• Whether there is diarrhoea alternating with constipation.

• Whether there has been a recent change in bowel habit.

• Any accompanying symptoms such as fever, vomiting, or loss of appetite.

• Any family history of inflammatory bowel disease or bowel cancer.

• Assessment of any risk factors such as:

  • Inadequate dietary fibre or fluids.

  • Lack of exercise.

  • Toileting habits that might predispose to constipation - eg, feeling hurried or being disturbed when trying to defecate, withholding or ignoring the urge to defecate, access to the toilet at home or work, and level of privacy.

  • Anxiety, depression, cognitive impairment, or an eating disorder.

  • Drug treatment or clinical features that might suggest an underlying organic cause of secondary constipation.

Examination:

Always perform a thorough examination of the abdomen to exclude abdominal tenderness, distension, masses, or a palpable colon (suggesting retained faeces).

A rectal examination should also be performed to look for:

• Anal fissures, haemorrhoids, skin tags, rectal prolapse, rectocele, skin erythema, or excoriation (may be a sign of faecal leakage).

• Resting anal sphincter tone.

• Rectal mass lesions and retained faeces (these may also be felt on external palpation around the anus). A faecal mass can be distinguished from a tumour or cyst, as firm pressure exerted by a finger will typically leave a palpable indentation in hard faeces.

• Pelvic floor dysfunction (if appropriate) - while asking the person to 'bear down', there may be paradoxical contraction of the anal sphincter on straining.

• Leakage of stool.

• Rectal or anal pain.

Causes of Constipation

Investigations

• Most constipation does not need investigation, especially in young, mildly affected patients.

• Indications for investigation include:

  • Age >40 years.

  • A recent change in bowel habit.

  • Associated symptoms (weight loss, rectal bleeding, mucous discharge, or tenesmus).

• Possible investigations include:

  • Blood tests: FBC, U&E, Ca++, TFTs.

• Referral may be required, depending on history, examination and investigation findings for consideration of:

  • Sigmoidoscopy and biopsy of abnormal and normal mucosa.

  • Special investigations (eg, transit studies, anorectal physiology) which are occasionally indicated.
    

Management⁴

• Treat the cause.

• Increase exercise.

• Increase fluid intake.

• Increase intake of high-fibre foods (including fruits, vegetables, whole wheat, and bran).

• Schedule bathroom time to try and open bowels.

• Consider CBT (this would rarely be available on the NHS but can be found online for free).

• Consider drugs only if the above measures fail.

• Try to use most drugs for short durations only - however macrogols can be used long term and should be used for at least as long as the constipation continued.

• Advise the person to gradually reduce and stop laxatives once they are producing soft, formed stool without straining at least three times per week. Review at regular intervals according to clinical judgement.

Drug therapy³

First line drugs include bulk laxatives and osmotic laxatives.

• Bulk laxatives:

  • Increase faecal mass which stimulates peristalsis.

  • Need to be taken with plenty of fluid.

  • Examples include ispaghula husk, bran powder, methylcellulose.

  • Contra-indications include difficulty in swallowing, intestinal obstruction, colonic atony, and faecal impaction.

• Osmotic laxatives:

  • Retain fluid in the bowel.

  • Examples include macrogols and lactulose.

  • Macrogols have been shown to be superior to lactulose for improving stool frequency per week, form of stool, abdominal pain, and the need for additional medications.⁶

Second line drugs include stimulant laxatives and stool softeners.

• Stimulant laxatives:

  • Increase intestinal motility.

  • Should not be used in intestinal obstruction.

  • Examples include bisacodyl, senna and docusate sodium.

  • Prolonged use should be avoided, as it may cause colonic atony and hypokalaemia (but there are no good, long-term follow-up studies).

  • Glycerol suppositories work as rectal stimulants.

  • Co-danthromer is a powerful stimulant laxative but has been associated with colonic and liver tumours in animal studies so is reserved for those patients towards the end of life.

• Stool softeners:

  • Lubricate and soften impacted faeces.

  • Side-effects can include anal seepage and malabsorption.

  • Should not be used for a prolonged period.

Third line drugs include enemas such as sodium phosphate or micralax. They can be useful as an adjunct in impaction.

Prucalopride⁷⁸

• Prucalopride is a selective serotonin 5HT₄-receptor agonist with prokinetic properties.

• Initially approved by the National Institute for Care Excellence (NICE) for women only, this can now be used for men and women who meet the criteria.

• Prucalopride is recommended as an option for the treatment of chronic constipation when treatment with at least two laxatives from different classes, at the highest tolerated recommended doses for at least six months, has failed to provide adequate relief, and invasive treatment for constipation is being considered.

• Initially it was recommended that prucalopride should only be prescribed by a clinician with experience of treating chronic constipation, who has carefully reviewed the woman's previous courses of laxative treatments. However NICE guidance no longer states this and some local formularies make provision for GPs to initiate prescribing.

Obstructed defecation syndrome⁹

• Obstructed defecation syndrome (ODS) is characterised by an urge to defecate but an impaired ability to expel the faecal bolus.

• Symptoms include unsuccessful attempts at faecal evacuation, excessive straining, pain, bleeding after defecation,, and a sense of incomplete faecal evacuation.

• Women, especially multiparous women, are more likely than men to present with symptoms of ODS.

• ODS is often associated with structural defects in the rectum, such as rectocele, internal rectal prolapse, and perineal descent.

• Conservative treatments include diet, biofeedback, laxatives, and pelvic floor retraining.

• Surgery may be considered for patients not responding to conservative treatment or if a structural abnormality is present, Surgical options include stapled transanal prolapsectomy, perineal levatorplasty (STAPL), stapled transanal rectal resection (STARR), and laparoscopic ventral mesh sacrocolporectopexy.

Severe constipation

For patients who fail to respond to conservative measures, other options may be considered.

These include:

• Transanal irrigation - water is introduced into the rectum by a catheter with inflatable balloon. It is controlled by a manual unit and has a pump, leg straps and a bag to hold the water. It is self-administered by the patient. A number of systems are available (eg, Peristeen®).¹⁰

• Sacral nerve stimulation - a minimally invasive procedure whereby an electrode is placed in a posterior foramen of the sacral bone.^{11 12}

• The Malone operation - this is also called an antegrade colonic enema (ACE). A small stoma is constructed from the appendix. Through the appendicostomy a catheter is inserted to administer an enema in the caecum. Usually 1 litre is given every second day to empty the whole colorectum. In patients who no longer have the appendix, a 'neoappendix' can be created from ileum or part of the caecum.¹²

• Surgery - colectomy with ileorectal anastomosis is reserved for a very small number of patients who do not respond to any other measures.¹²