New Zealand Doctor F 6 June 2007 F 33

HOW TO TREATDetailed treatment updates for common conditions

constipation

Most patients experience constipation at some time, and the causes are many. It is important for GPs to distinguish between acute and recent onset and chronic constipation, and whether there is an obstruction causing constipation or constipation causing obstruc-tion. In children, congenital conditions and toilet training issues also need to be borne in mind. This article is a review of constipa-tion and its management in adult and child populations. The article was written by Rod MacLeod, a palliative care specialist at North Shore Hospice, Auckland and Pat Boulton, medical officer at the Child and Adolescent Community Centre, Taranaki Base Hospital.

• Strainingduringatleastoneinfourbowelmovements.• Pellet-likeorhardstools forat leastone in fourmove-

ments.• Sensation of incomplete evacuation for at least one in

four movements.• Sensationofanalblockageforatleastoneinfourmove-

ments.• Usingmanualmanoeuvres(includingdigitalevacuation

or pressure on the perineum) to facilitate more than one in four movements.

• Havingnomorethanthreemovementsperweek.Of relevance is a premorbid bowel history. Patients may

also report increased flatulence, bloating, abdominal pain and feeling of incomplete evacuation.

Not passing stools for a few days does not generally cause significant physical discomfort but it can cause psy-chological distress to some people. People generally do not come to any harm if they do not open their bowels frequent-ly but of course any change in bowel habit should be taken seriously and investigated thoroughly.

Consequently, the investigation and management of con-stipation can take up a significant part of a GP’s time. In one UKstudyofchronicconstipationinthecommunity,itwasestimated 10 per cent of community nursing time is spent on constipation – so whichever way you look at it is a major healthcare issue.

Constipation is common and is reported to affect 10 per cent of the population, with gender prevalence for females. In the elderly population, prevalence ranges from 15 to 20 per cent in commu-nity dwellers and up to 50 per cent in some studies of residential care facilities.

Constipation accounts for about 3 per cent of general paediatric outpatient visits and 25 per cent in a paediatric gastroenterology clinic. Studies sug-gest primary care health professionals currently tend to undertreat children with constipation.

One review suggests there are over 2.5 million USconsultationsannuallyforconstipationalone.InNew Zealand and other developed countries, physi-cal illness, poor diet, advancing age and hospitali-sation are major risk factors.

For a number of reasons, there is also a much higher incidence in those who are terminally ill. OneUKreportsuggestshalfof thoseadmittedtoinpatient hospices are constipated; this does not include those adequately treated with laxatives.

There could be a wide variation in what people think of as constipation – 95 per cent of adults have between three and 21 bowel movements a week. Children have a simi-lar wide range of movement frequency and breastfed babies have an even wider range.

In children, constipation is often accompanied by soiling past the age of toilet training. In fact, this becomes the domi-nant complaint as the constipated child develops. A “quick fix” is often not possible for child constipation with soiling.

From a medical perspective, diminishing frequency to fewer than three bowel movements a week is one defi-

nition of adult constipation, but there is no general agree-ment. Generally speaking, the passage of small, hard faeces infrequently and with difficulty is an accepted definition. However, this may not be satisfactory or easy to identify. In children, the definition traditionally centres on a delay or difficulty in defecation present for two weeks or more, but it also includes the hardness and size of the stool.

One other definition for the adult diagnosis is that two of the following six criteria are present for at least 12 weeks in the preceding months.

Problem prevalent but definitions vary

1 The normal state of the rectum is to be empty. True/False2 The prokinetic cisapride can be used as a laxative. True/False 3 Faecal impaction can be treated with oral medication. True/False4 Child constipation can be the cause of day wetting. True/False5 Hirschsprung’s disease is always diagnosed

in the neonatal period. True/False

Answers on page 37

Do you need to read this article?Try this quiz

HOW TO TREAT CONST IPAT ION

34 F 6 June 2007 F New Zealand Doctor

Constipation is the result of an upset in normal bowel function. Intestinal motility patterns have two functions:• mixing the bowel contents, which facilitates the enzy-

matic digestion initiated by the saliva, and• burstsofforwardpropulsivemotoractivity(every90to

120 minutes) in the small bowel, and six times a day in the large bowel, grouped at wakening and midday. Motility is coordinated by the myenteric nerve plexus

and may be modulated by the wider nervous system, mainly via the parasympathetic system. From there, the smooth muscle layer of the intestinal wall propagates the impulse.

During defecation, abdominal pressure is raised by ab-dominal muscle contraction and is facilitated by squatting. This is a step many debilitated and relatively immobile pa-tients find difficult. Once initiated, by distension of the rectal wall, an anocolonic reflex produces distal colonic contrac-tion, continuing the process of defecation. Anorectal sensitiv-ityreduceswithage.Undernormalcircumstances,therefore,defecation means adopting a suitable posture, contracting the diaphragm and abdominal muscles, and relaxing the puborectalisandexternalanalsphinctermuscles(Figure1).

Low spinal cord lesions produce colonic dilatation, re-duced transit in the transverse and descending colon and reduced rectal sensation. Higher lesions also reduce the mixing response to food ingestion.

Causes of constipation

Thecausesofconstipationareoftenmultiple(Table1)and include medications (Table 2). Alterations in colonic

GI motility under nervous control

Figure 1. Anatomy of the descending colon, rectum and anal sphincters. Pelvic floor dysfunction may inhibit the normal dynamics of defecation

diet decreased bulk/low residue diet milky foods reduced food intake

dehydration reduced fluid intakevomiting excessive sweatingtachypnoea

immobility

hormonal disorders

hypothyroidism hyperparathyroidism ?altered oestrogen and progesterone

pain

medication use see Table 2

partial obstruction tumour (cancer of the rectum or colon) adhesions, strictures

disease affecting colon

scleroderma Hirschprung’s disease (congenital megacolon)Chagas disease (trypanosomal disease causing megacolon)irritable bowel syndrome

neurological nerve compressionneuropathy depression multiple sclerosisParkinson’s disease

metabolic disturbance

hypercalcaemiahypokalaemiahypermagnesaemia chronic renal failurecongestive heart failurediabetes mellitus

concurrent problems

painful haemorrhoidsanal fissurespelvic floor dysfunction

Table 1

Drug class Generics Constipating mechanism

antacids aluminium hydroxide, calcium salts astringent action may cause constipation

hypolipidaemics

iron

cholestyramine

ferrous sulphate

decreased bowel motility, dehydration or fluid restriction may cause intestinal obstruction; haemorrhoids and fissures, or faecal impaction, may occur

anticholinergics (anti-parkinsonian drugs)

atropine-like drugs

dopaminergics

benztropine, benzhexol

orphenadrine

levodopa

inhibition of acetylcholine action on smooth muscle, leading to reduced bowel tone and motility

antidepressants (tricyclic) amitriptyline, nortriptyline, imipramine anticholinergic action on bowel smooth muscle wall

tranquillisers (phenothiazines)

chlorpromazine, trifluoperazine, thioridazine myenteric plexus damage can occur, causing chronic constipation and pseudo-obstruction; faecal impaction could result in local inflammation (chronic and acute), ulceration, bleeding and even perforation

antineoplastics vincristine upper colon impaction may occur; paralytic ileus, particularly in young children and the elderly, can occur

opioid analgesics codeine phosphate, dextro propoxyphene, morphine, oxycodone, methadone, fentanyl

an increased resting tone of bowel smooth muscle is associated with reduced propulsion and force of peristaltic contractions

antihistamines diphenhydramine, promethazine, trimeprazine intrinsic anticholinergic activity

laxatives senna, bisacodyl chronic use (abuse) leads to loss of smooth muscle tone (atony) and contractility, which inhibits normal peristalsis; results in “cathartic colon”

diuretics (non-K+ sparing) chlorthalidone, thiazides, frusemide dehydration can cause hard faecal mass; high use of K+ supplements can cause ischaemic ulceration, which heals with fibrosis and partially obstructs the bowel

antihypertensives

antiarrhythmics

clonidine

verapamil, disopyramide

not known, but constipation common

Table 2

structure and function in the elderly include decreased rec-tal compliance, increased sensory threshold for an urge to defecate and decreased resting and squeezing pressures in the anal canal.

Puborectalis muscle

Internal anal sphincter

External anal sphincter

Pubic bone

Descending colon

Sigmoid colon

Rectum

HOW TO TREAT CONST IPAT ION

New Zealand Doctor F 6 June 2007 F 35

Adult constipation: careful history key

Accurate diagnosis, as always, depends on an accurate history. Enquiry should be made about stool frequency and consistency and possible associated symptoms, eg, nausea, vomiting, pain and distension. Time taken attempting to evacuate the bowel is also relevant.

Symptoms and signs associated with constipation are multiple, and may include anorexia, bloating, abdominal discomfort/cramping, spurious diarrhoea, confusion and anxiety.

If severe, symptoms can progress to a functional bowel obstruction with either hyperactive (but not obstructed)bowel sounds or a relatively silent abdomen. This can be resolved by treatment of the constipation. It is therefore important to differentiate between constipation and bowel obstruction as, in the latter, the use of stimulant laxatives can cause painful colic.

A skilled assessment is particularly essential when managing people who are dying and includes a history of these symptoms in conjunction with physical examination findings.

General physical examination may elicit nothing abnor-mal, but it may reveal a palpable and often indentable colon,

both right and left sided. A neurological examination should be performed, looking for focal deficits or evidence of disor-ders such as hypothyroidism.

Rectal digital examination is necessary to exclude local disease and assess the consistency and amount of faeces in the rectum. Abnormalities to look for are anal fissures, strictures,masses(eg,cancers)orhaemorrhoids.Digitalex-amination also elucidates whether anal internal sphincter tone is normal. It also gives an indication of the strength of the external sphincter and the puborectalis muscle. Stool amount and consistency can indicate much. More stool is present with colonic inertia for example.

Stool examination is helpful but often impractical. A vis-ualaidsuchastheBristolStoolChart(Figure2)can,how-ever, be invaluable.

The normal state of the rectum is to be empty. However, in difficult situations, where the rectum is empty and inter-vention has not produced any result, but constipation is still suspected, an abdominal x-ray may be of use in assessing faecal loading. Stools should be tested for occult blood.

Laboratory studies and colorectal imaging are appro-priate when constipation fails to respond to conservative

measures – imaging should not be undertaken as an initial investigation. Plain x-rays of the abdomen have been par-ticularly useful in paediatrics, geriatrics and palliative care. Radiography can only be interpreted in conjunction with a full and accurate history though.

Flexible sigmoidoscopy and colonoscopy are the most appropriate methods of identifying narrowings that may ex-acerbate slowing of the passage of stool. More sophisticated options(eg,analmanometry,ballooninsertionanddefecog-raphy) are generally not used unless absolutely essential.

Anal manometry is useful in assessing anal sphincter tone as well as pelvic floor strength and hence pelvic floor dysfunction. Balloon insertion is a relatively simple way of demonstrating evacuation – normal volunteers can expel a balloon whereas people with pelvic floor dysfunction can-not. Defecography is self-explanatory really, the rectum is filled with thickened barium and the patient is asked to sit and expel the barium while being monitored.

Constipation is associated with a delayed or prolonged gut transit time so methods of measuring the time are key to an extensive investigation. The various methods range from repeated abdominal radiography looking for bismuth trac-ers(nolongerusedbecauseoftheradiationdoses)tomoresophisticated methods such as scintigraphy, radiotele metry capsules and radio-opaque polythene marker pellets. Col-oured markers can be used if radiography is difficult to ac-cess but stools need to be examined and possibly sieved to find the pellets as they emerge.

Type 1 – Separate hard lumps, like nuts (hard to pass)

Type 2 – Sausage-shaped but lumpy

Type 3 – Like a sausage but with cracks on its surface

Type 4 – Like a sausage or snake, smooth and soft

Type 5 – Soft blobs with clear-cut edges (passed easily)

Type 6 – Fluffy pieces with ragged edges, a mushy stool

Type 7 – Watery, no solid pieces. ENTIRELY LIQUID

Figure 2. Bristol Stool Form Scale. Reproduced with the kind permission of KW Heaton. Tick indicates normal

HOW TO TREAT CONST IPAT ION

36 F 6 June 2007 F New Zealand Doctor

Two of the most effective general measures for constipa-tion are to encourage patients to be as mobile as possible, within their limitations, and to ensure they are provided pri-vacy for defecation.

One of the most useful things to do initially is to review all medications being prescribed or taken, to ensure all pos-sible iatrogenic causes are minimised.

A review of diet and fluid intake is also an essential step. Very few studies demonstrate the most appropriate dietary advice but common sense dictates an increase in fibre, if possible, will help. Similarly, advice on fluids is helpful. De-hydration is a key risk factor and has been showed to slow transit time in some observational studies. Care needs to be taken not to overload the elderly with fluid however: 1.5L/day is the suggested minimum fluid recommended for the prevention and treatment of chronic constipation.

Laxative use for adult constipation

Laxatives are commonly divided into five broad groups:• fibreandbulkforminglaxatives• osmoticlaxatives• stimulantlaxatives• stoolsofteners,lubricantsandsuppositories• others.

Fibre and bulk forming laxativesThe most common fibre and bulk forming laxatives are

those containing psyllium, bran, methyl cellulose, isphagula and polycarbophil, and most have been available for some time. They work by increasing the weight and water absorp-tion of stools, so enabling quicker propulsion along the gut lumen. To use these laxatives, patients need to be able to drink a significant quantity of water, so discounting their use in some frail or elderly people.

Flatulence and distension are common accompaniments but this group of laxatives is considered by many to be the first, most effective step in patients with normal transit constipation.

Osmotic laxativesOsmotic laxatives include mixed electrolyte solutions

containing polyethylene glycol (PEG) and non-absorbablesugars such as lactulose and sorbitol.

Lactulose can take up to two or three days to have an effect, so is not suitable for rapid relief of constipation. The main adverse effects are flatulence, transient abdomi-nal cramps and hypokalaemia. Sorbitol is similarly a non-absorbable sugar alcohol that has an osmotic action that works in the colon. Again abdominal pain and flatulence are common side effects.

The latest additions to this group – the macrogols – are promising and may be particularly useful for those with fae-cal impaction and constipation related to opioid usage.

Polyethyleneglycol(PEG)isaniso-osmoticlaxativethatbinds water molecules. This group of compounds has been used widely for bowel preparation before investigations or surgery – it is not absorbed but works by virtue of its os-motic effect, which increases stool volume and increases peristalsis.

The electrolytes present in PEG are such that there is virtually no net gain of sodium, potassium or water, so they are relatively safe compared with some others in this group. Each sachet needs to be dissolved in 125ml of water. This may be a problem for those unable to consume adequate fluid. However, the fluid does not need to be taken immedi-ately, so frail and very sick people may be able to tolerate this volume over time.

Studies indicate PEG is effective in the management of faecal impaction as well. This, combined with its relatively low incidence of side effects, makes it an attractive addition to the therapeutic armamentarium.

Osmotic laxatives seem to be the most effective group overall.

Stimulant laxativesStimulant laxatives produce an increase in peristalsis

and mucus secretion. They are probably the most widely used type, despite less their favourable side effect profile.

Mostcommonare theanthraquinones (senna, cascaraandaloes)anddiphenylmethanecathartics(bisacodyl,so-dium picosulphate). Castor oil may be the best known of this group but it is no longer widely used because of adverse effects such as malabsorption and dehydration.

These laxatives, because they stimulate the myenteric plexus, have been the logical choice for the management of opioid-induced constipation. Laxative effect is dose depend-ent. At high doses, they inhibit water and sodium absorp-tion so, potentially, they can cause disturbing electrolyte imbalances, eg, hypokalaemia.

Bisacodyl is available in oral and rectal forms, the latter being useful for those with outlet delay. Glycerine acts as a stimulant when given rectally – glycerol being mildly irritant.

Some studies have attempted to identify the most effec-tive stimulant but no clear leader has emerged. No doubt these laxatives will continue to be used widely but attention needs to be directed at their adverse effects to ensure they are minimised.

Stool softenersDocusate sodium is the most common softening laxative

– it also has a weak stimulant effect. It is thought to stimu-late intestinal secretions and increase penetration of fluid into faeces, softening the stool. It is often combined with stimulants.

Liquid paraffin is also a softener but is rarely used in clinical practice now because of potential and real side ef-fects such as anal seepage, irritation and lipoid pneumonia.

Other drugs with bowel transit effectsProkinetic drugs have been used to increase gut motility.

Primarily used for upper gastrointestinal disorders, cisap-ride has been shown to promote peristalsis at the colonic level and to induce defecation. Cisapride should no longer be used as a laxative however because of potential side ef-fects and drug interactions.

Newer 5-HT4 receptor agonists are potentially effective laxatives.Attentionisfocusedonprucalopride(aninvesti-gational drug with prokinetic effects) and tegaserod, which is available and stimulates the peristaltic reflex resulting in decreased gut transit time and, therefore, effectively man-ages some forms of constipation.

Colchicine increases bowel movement frequency and decreases colonic transit time but it is currently not recom-mend for widespread use.

Misoprostol, a synthetic prostaglandin E1 analogue used for prevention and treatment of NSAID-induced peptic ulcer disease, has diarrhoea as a common side effect. In theory, it should be useful in managing constipation; however, studies have not been helpful to date.

Enemas Enemas induce bowel movement by distending the co-

lon and rectum. In many palliative care centres, for example, if the faeces are hard, a milk and glycerine enema is used.

Phosphate enemas are used for high faecal loading and should only be used as acute treatment for severe constipa-tion when a milk and glycerine enema has failed. Phosphate enemas have a laxative effect as a result of their osmotic properties – electrolyte disturbance may occur.

The choice of enema can vary, often depending on cus-tom. They are quite aggressive treatments in the very sick patient, consuming a lot of energy.

If there is no result from the above measures, an over-nightoilretentionenema(40mlwarmedoilperrectumviaalong rectal tube; elevate foot of bed to aid retention) should be given to soften the faeces followed by a stimulatory en-ema the following morning. The efficacy of this is relative to the ability to retain the oil in the rectum.

Diet, mobility and laxatives can help

LAXATIVE ABUSE

Laxative abuse occurs when someone attempts to lose calories or weight through repeated, frequent misuse. Often, misuse fol-lows eating binges, when the person mistakenly believes the laxative will quicken transit of food and calories through the gut before they can be absorbed. There is a helpful guide to the problems of laxative abuse at www.nationaleatingdisorders .org with information about symptoms and signs, potential problems and management strategies. Generally speaking, if lax-ative abuse is suspected, referral to specialist services for eating disorders is most helpful.

For patients who have a large amount of hard faecal mat-ter they are unable to expel, a manual removal should be considered. For patient comfort, this is best done after a mild sedative.

Non-pharmacological interventions

Aromatherapy and massage have seen a revival, particu-larly in oncology and palliative care communities. There is little, if any, evidence to support aromatherapy use in this way, but it remains popular when combined with abdominal massage. Acupuncture is also utilised in the management of constipation – one palliative care study failed to show any benefit though. Reflexology, another ancient form of prac-tice, may be of some benefit in certain situations.

The drug or the disease?

Presentation and history: Bob is 64 years old and had sur-gery and chemotherapy last year for colorectal cancer. Initially, he did very well and returned to work, but over the last three months he has needed to increase his regular opioid analgesic and finds he is increasingly uncomfortable and has been unable to open his bowels for four days. Prior to that, he had been unable to empty his rectum properly with a feeling of fullness most of the time. He has episodes of nausea but no vomiting; he has not lost any weight. The GP considers this could be related to the opioids or advancing disease.

Examination: Physically, Bob is normal except that abdominal examination reveals his laparotomy scar with some mild ten-derness beneath it. There is a suspicion of a palpable colon and his rectum is full of soft stool.

Diagnosis: The GP diagnoses constipation related to opioid use. He feels no further examination or investigation is needed at this stage.

Management: The GP tells Bob his thoughts on the prob-lem. Bob then admits he has not been taking his normal laxa-tive (coloxyl and senna, two tablets twice a day) as he did not like the effects; he has been taking some of his wife’s lactulose though. The GP prescribes the propulsive stimulant bisacodyl 10mg (two tablets) daily up to a maximum of 10mg twice daily. Bisacodyl, a myenteric plexus stimulant, is a logical choice for managing opioid-induced constipation, and its effect is dose de-pendent. (At high doses, it inhibits water and sodium absorption so, potentially, it can cause disturbing electrolyte imbalances, eg, hypokalaemia.) The GP advises Bob he’ll need to take the laxa-tive regularly as long as he is using opioids and, if the opioid dose increases again, an increase in the laxative will likely be needed. He also encourages Bob to keep his fluid intake high and to eat fruit and fibre when and if he can.

Case study 1

The least used room in the house

HOW TO TREAT CONST IPAT ION

New Zealand Doctor F 6 June 2007 F 37

Childhood constipation is often accompanied by soiling past the age of toilet training. This becomes the dominant complaint with age as peer and social pressures increase. Toilet training difficulties also occur in the presence of constipation.

The definition of constipation in children can vary wide-ly. Traditionally, it is a delay or difficulty in defecation pre-sent for two weeks or more but also includes stool hardness and size.

There is a lot of variation in stool firmness and frequency in healthy babies and children. Breastfed babies may pass a stool after each feed or only once every seven to 10 days. Bottle fed babies usually have a bowel movement daily or at least every second day. The normal infant’s stool is of a consistency that allows moulding to the bottom.

Two-year-olds, on average, have 1.7 stools per day reduc-ing to 1.2 per day as four-year-olds. If frequency is less than once every three days, the child is likely to be constipated.

Constipation without objective evidence of a pathologi-cal condition is most often caused by a painful bowel move-ment resulting in voluntary withholding of faeces by a child who avoids defecation for fear of further pain. Hard stools may result in tears to the anal skin and present with red blood on the stool.

Abdominal pain relieved by passing a stool is sometimes a feature. Constipation can also be associated with an in-creased risk of urinary tract infections, daytime urinary in-continence and bedwetting.

Examination for chronic constipation

Chronic constipation creates anxiety for parents who worry a serious disease may be the cause. Only a small mi-nority of such cases has an organic cause.

A detailed history and physical examination is usually

sufficient to make a diagnosis of functional constipation. This includes charting height and weight, examining the abdomen and spine, neurological examination of the legs (includingtone and reflexes) as well as observation of the anal area.

A rectal examination may give information about the quantity and nature of stools in the rectum.Unnecessaryrectal examinations are discouraged though and may be left to secondary or tertiary care. Perianal soiling is typically seen in children with stool retention with overflow.

Investigations or onward referral are needed only for ab-normalphysicalfindingsorothersymptoms(Panel1).Inter-preted correctly, a plain abdominal x-ray can be a useful tool in the diagnosis of faecal impaction.

Most organic causes present early in life. Long-segment Hirschsprung’s disease usually presents neonatally or in ear-lyinfancy.Ultrashort-segmentHirschsprung’smay,however,present later as constipation. The condition has a prevalence of one in 5000, and a definitive diagnosis is made by rectal biopsy to identify aganglionosis. A history of passing very large stools at any stage makes the diagnosis very unlikely.

Functional causes are more common

There are many other possible factors responsible for constipation. These include increased transit time due to slower gut motility – delayed passage of stool through the colon results in harder, drier stools. A poor diet and insuf-ficient fluids can compound the problem.

Physical and developmental problems can reduce the child’s physical mobility.

A history of stool withholding behaviour reduces the likelihood of an organic disorder. A child may assume strain-ing and squatting postures, which parents wrongly interpret as genuine efforts to defecate.

With increasing age, bowel habits are important. A child can become constipated if he or she ignores the urge to pass stools when busy or fails to fully empty the rectum when rushed. Events that can lead to problems are toilet training methods, changes in routine and diet, stressful events, inter-current illness and unavailability of acceptable toilets.

If stool retention continues, the bowel becomes over-

Child constipation a worry for parents

Summary of main referral criteria

• failure of treatment regimen• abnormal physical findings• accompanying vomiting• failure to thrive • blood or mucus in the stool• anal stenosis • a tight empty rectum• abnormal leg neurology• developmental problems

Panel 1

loaded and stretches resulting in a loss of sensation of the need to defecate. Soiling becomes more likely, with faeces appearing unnoticed in the pants when the child relaxes, is asleep, in the bath or shower or after food and exercise. Very soft stool can trickle out past the hard stuff. The child has no idea this is happening and can find it very distress-ing. A presenting feature can be the hiding of soiled under-wear or hiding to defecate.

By the time the child sees the GP the original cause may have long since gone.

Quiz answers1. True 2. False 3. True 4. True 5. False

School starts soon

Presentation and history: James, a four-year-old, is dry day and night apart from occasional day wetting episodes but he does not regularly use a toilet for defecation. He often soils himself but is unaware of doing it. His mother finds soiled pants hidden away. She is increasingly frustrated and angry with James, calling him lazy. He starts school soon. James’ history reveals he passed meconium normally on day one and had no problems in his first year. He has had episodes of constipation since 2.5 years when toilet training began. Lactulose has been used irregularly. He often refuses to sit on the toilet.

Examination: Physically, he is normal except that rectal exam-ination finds loading with firm stools and some perianal soiling.

Diagnosis: The GP diagnoses functional constipation with overflow. A plain x-ray confirms a very full rectum with over-loading of the colon generally.

Management: The GP informs the parents of what is happen-ing to James using visual aids, explaining the soiling is not his fault. The GP tries to relieve the impaction by prescribing macrogol 3350 (Movicol-Half) – two sachets (60ml water per sachet) on day 1, increasing by two sachets on days 2, 4 and 6 until clean out or day 7, whichever is sooner. For maintenance, the GP switches James to lactulose syrup 1ml/kg/day, adjusting down or up to 2 or 3ml/kg/day as needed. The GP advises a regular toi-leting programme and suggests James uses a footstool to sup-port his feet. A reward system to encourage good sitting and bowel actions is discussed – avoiding rewards for clean pants as this encourages retention. Increased fruit and fibre, water intake and exercise are also strongly recommended. The parents are asked to keep a record of laxatives given and bowel actions on a chart provided, for review at the next visit. The GP organises regular family contact and support with the practice nurse or public health nurse.

Follow up: At a four-week visit, the soiling has stopped though a regular bowel habit is taking time to achieve, and relapses still occur now and then. The day wetting has stopped. James’ mother comments his appetite is much better and he is a hap-pier child. The GP advises the parents support the programme for as long as needed.

Case study 2

If frequency is less than once every three days, the child

is likely to be constipated

HOW TO TREAT CONST IPAT ION

38 F 6 June 2007 F New Zealand Doctor

Further resourcesBosshard W, et al. The treatment of chronic constipation in elderly people Drugs Aging 2004; 21: 911–30.Fallon M, O’Neill B. ABC of palliative care: constipation and diar-rhoea. Br Med J 1997; 315: 1293–6.Kyle G. Constipation and palliative care – where are we now? Int J Palliat Nurs 2007; 13: 6–16.Ramkumar D, Rao SS. Efficacy and safety of traditional medical therapies for chronic constipation: systematic review. Am J Gas-troenterol 2005; 100: 936–71.Evaluation and treatment of constipation in infants and children: recommendations of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition. J Pediatr Gastroen-terol Nutr 2006; 43(3): e1–13.Clayden G, Keshtgar AS. Management of childhood constipa-tion. Postgrad Med J 2003; 79: 616–21.F de Lorijn, et al. Prognosis of constipation: clinical factors and colonic transit time. Arch Dis Child 2004; 89: 723–7.Borowitz SM, et al. Treatment of childhood constipation by primary care physicians: efficacy and predictors of outcome. Pediatrics 2005; 115: 873–7.Candy DCA, Edwards D. The management of chronic constipa-tion. Curr Paediatr 2003; 13: 101–6.Burnett CA, et al. Nurse management of intractable functional constipation: a randomized controlled trial. Arch Dis Child 2004; 89: 717–22.

UsefulwebsitesKiwi Enuresis Encopresis Association (KEEA) www.keea.org.nzNew Zealand Continence Association (NZCA) www.continence.org.nzEducation and Resources for Improving Childhood Continence www.eric.org.ukPaediatric Society of New Zealand (Kidshealth) www.kidshealth.org.nz

While constipation is a common paediatric problem, no evidence-based guideline for evaluation and treatment exists. Advice is based on expert opinion, but studies are ongoing.

For mild constipation, simple measures can be tried first. For infants, prune, pear or apple juice that contains sorbi-tol – coupled with increased water intake – may help. In chil-dren aged over 15 months, more dietary fibre can help. This can be achieved via at least three servings of fruit plus three servings of vegetables a day, along with high fibre cereals and wholegrain breads. Advise parents to cut out junk food and avoid refined sugars. Some children benefit from a reduced milk intake. The whole family will benefit from more exercise.

In children with a more severe problem, a laxative is need-ed. A quick fix is often not possible if there is constipation and soiling. Two years of management is not unusual. In one study, a third continued to have problems with chronic con-stipation seven years after initial treatment. It is essential to explain the problem to family and visual aids can be useful.

Laxative choice depends on GP and parental preference, safety, side effects, cost and palatability and, to a large extent, acceptability to the child. Children with impaction require disimpaction first. This can be achieved by use of an oral lax-ative or rectal enema. The latter is more invasive but faster.

After disimpaction, a maintenance regimen is necessary, adjusting medication to produce a regular movement of soft stool on at least alternate days. Complete evacuation of the rectum is needed for normal bowel function to return. The laxativedose isoftenhigher thanpreviouslyadvised (seebelow). Maintenance therapy for six months is recommend-edbeforeattemptsatweaningoff(Figure3).

A regular toileting programme with behaviour modifica-tion techniques and a laxative have been shown to work bet-ter than any intervention alone.

Toilet sitting for five minutes in a good position, with the feetraisedslightly(Figure4), forabout10minutesafterameal is to be encouraged to take advantage of the gastro-colic reflex. After breakfast or the evening meal, as well as on returning from school, are good times for some children. Supervision is often needed. Daily bowel diaries recording laxative use, the frequency, size and consistency of stools, and the presence or absence of soiling are useful. The Bris-tol Stool Chart is helpful; every practice should have one.

For children who soil, regular contact with a supportive professional is needed, as parents need encouragement to maintain a consistent positive attitude with their child.

Successful long term treatment requires a family to be well organised, as interventions are time-consuming and patience is needed to put up with gradual improvement and relapses.

If a treatment programme fails, further investigations are needed. Blood tests should include thyroid function, calci-um and antibodies for coeliac disease.

Use of medications in children

Many laxatives are available over the counter but in chil-dren they should only be used with medical advice. Some are subsidised on prescription. There are no validated pro-tocols for laxative use in children and their use should be adjusted according to need, with dosages individualised. Basic dosages for some are outlined below.

Stool softeners, and bulking and osmotic laxativesLactulose – a synthetic disaccharide – is a commonly used

liquidstoolsoftenerandiswelltoleratedbychildren(dosage1–3ml/kg/day in divided doses). It can produce flatulence and abdominal cramps and may take up to 48 hours to work.

Poloxamer oral drops are a softener suitable for children under the age of three years and for babies. Docusate sodi-um tablets, for older children, are a stimulant and a softener.

Liquid paraffin/mineral oil is not recommended in under one-year-olds or if there is any risk of aspiration (mainte-nance dosage 1–3ml/kg/day). This is more palatable if chilled.

Other options not subsidised on prescription include milk of magnesia, macrogol 3350 and sodium picosulphate, while psyllium husk can be part or fully subsubsidised.

Milkofmagnesia(magnesiumhydroxide8percentsus-pension)canbegiven (1–3ml/kg/dayup toamaximumof50ml). The pharmacist must dilute it from paste. It is not palatable to all children but is useful as it is a mild stimulant causing the release of cholecystokinin. Infants are suscepti-ble to magnesium poisoning, so it should be used with cau-tion in renal impairment. It is useful for clearance in mild cases and can work quickly.

Macrogol 3350 is a useful laxative, new to New Zealand butusedforsomeyearsintheUK,EuropeandAustralia.Itis a powder that is mixed with water, can be flavoured with cordial and does not have to be taken all at once. It can be used to clear faecal impaction and for maintenance and is good for children with hard stools from the age of two years. Macrogol 3350 takes water through the bowel to the colon keeping more water in the faeces. A clearance regimen of up to seven days is available for children of different ages, stop-ping when disimpaction occurs.

Sodium picosulphate is a powder, mixed with water, that can be flavoured. It is also useful for impaction if used over a few days in children over two years. Plenty of water needs to be drunk and it should only be used with medical advice.

Psyllium husk is a bulking laxative containing fibre, which needs to be mixed with water. It comes unflavoured and or-ange flavoured and is not suitable for children under six years of age. All psyllium husk preparations need a glass of water after each dose.

Stimulant laxativesStimulant laxatives are not recommended for long term

use but are useful in some paediatric situations. Senna, given at night in tablet form, can reduce cramp-

Treatment of child constipation

ing and encourage a bowel movement in the morning before school. It can be used with or without a softener. Melanosis colic improves after stopping the medication.

Enemas and suppositories These are unpleasant for a child, causing pain and em-

barrassment and can usually be avoided.However, sodiumcitrateenema (withotheractives) is

useful for rectal constipation only but can produce a rectal burning sensation. Phosphate enemas, if used, need care to avoid trauma and toxic effects. For glycerine and oil high enemas, the dose depends on the child’s age. Glycerine sup-positories are mildly irritant and of limited use. D

Figure 3. A summary of the diagnosis and management of idiopathic constipation and soiling in children. Levels of evidence: (A) randomised controlled trial; (D) expert opinion. Guideline reproduced with permis-sion from Felt B, et al. Arch Pediatr Adolesc Med 1999;153:380–5

Figure 4. Correct position for defecation. Reproduced with the kind per mission of Ray Addison and Wendy Ness, Mayday Healthcare NHS Trust

Knees higher than hipsLean forwards and put elbows on your knees

Bulge out your abdomenStraighten your spine

• Evaluate and man-age other disorder

• Consider managing constipation and soiling concurrently

YES

Symptoms and signs suggestive of constipation and soiling

Are symptoms and signs of another disorder present?

Diagnosis of idiopathic constipation and soiling

Patient and caretaker education (D)

Impaction present?

Prescribe clean-out (disimpaction) (D)

Is disimpaction effective? (preferably determined by physical examination)

Maintenance therapy using multimodal approach for 6 months minimum

is strongly recommended (A)

Wean from laxatives after 6 months (D)

Stool frequency <3 per week or any soiling?

• End full maintenance programme• Continue behavioural and dietary components• Follow up according to usual health supervision

YES

NO

YES

YES

NO

NO

YES

NO