Constipation in infants and children

Remember

• Constipation affects up to 30% of children, and peak incidence is at the time of toilet training.^1-3
• Constipation is defined by the frequency of stooling (fewer than two per week in children over 4 years of age), but more importantly by stool consistency and difficulty with which stools are passed (Case Study 1, Box 1).
• Constipation arising beyond the neonatal period is usually functional constipation; this diagnosis can be made clinically after a careful history and physical examination, looking for red flags that may suggest organic pathology.
• Faecal incontinence (encopresis) develops in up to 50% of children with chronic untreated constipation and has a significant psychosocial impact.⁴
• Management of constipation is often a long-term process that requires the complementary approaches of careful education of the child and parents, behavioural techniques, laxative agents and review.

Assessment

• Take a detailed toileting history (Box 2) and consider whether the child meets the Rome IV criteria for functional constipation (Box 3).³
• Check for red flags suggestive of an organic cause for constipation (Table 1).
• Perform a thorough physical examination: assess growth, palpate the abdomen for faecal masses, inspect the perianal and lumbosacral areas; and perform a lower limb neurological examination.
• Avoid digital rectal examination in primary health care as it rarely contributes to the clinical assessment and is distressing to the child.
• If the likely diagnosis is functional constipation then no further investigation is required. Abdominal x-ray is not required to diagnose constipation or determine response to therapy.^3,5
• Consider coeliac serological testing in children with constipation and poor growth, a history of recurrent abdominal pain, poor response to treatment or a family history of coeliac disease. Measurement of thyroid stimulating hormone levels is recommended in children with impaired height growth, depressed reflexes or a history of central nervous system disease.⁶
• If a pathological cause for constipation is suspected, then appropriate investigations should be performed fin consultation with a paediatrician or paediatric surgeon.

Management

• Successful long-term management of childhood constipation requires a combination of education, behavioural measures and laxatives. Behavioural measures combined with laxative therapy are superior to either therapy alone in children with faecal incontinence.⁷
• An explanation of the relationship between stool withholding behaviour and functional constipation should be given to parents. For example, ‘Children who experience pain from hard stools start to avoid going to the toilet, leading to more stool building up in the lower bowel. They eventually develop an overstretched rectum, which holds a large amount of stool that becomes harder and more difficult to pass, encouraging more holding on.
• We need to use a combination of behavioural strategies and laxative medicine to stop this cycle’.

Laxative therapy

• Faecal impaction is often signified by palpable abdominal faecal mass and accompanied by faecal incontinence, known as encopresis (Case Study 2, Box 4).^8,9 This requires a disimpaction regime. First-line disimpaction is with oral macrogol 3350 at a dose of 1 to 1.5 g/kg per day. A guide to approximate starting doses is provided in Table 2. Disimpaction doses are needed for at least four days and often for up to a week, until rectal effluent is free of lumps and there is no longer a palpable abdominal mass. Use of enemas or suppositories is rarely indicated in the primary health care setting.
• Maintenance laxative therapy should be commenced straight after disimpaction and is often required for many months after normalisation of stools so behavioural modifications have become routine and a distended rectum can return to a normal calibre. Maintenance doses will need to be adjusted in small increments to achieve the passage at least every one to two days of easily passed soft stools.
• Continue maintenance treatment until the child has been free of symptoms for three to six months. Many children will require laxatives long term, and parents should be reassured that this is both safe and appropriate, particularly in the case of osmotic laxatives.
• We recommend the use of macrogol in children of all ages because studies have found it to be equal to or more effective than other therapies and to be the most tolerable as it can be mixed with almost any fluid.^10,11
• Oral macrogol has been found to be as effective as enema therapy for disimpaction, so rectal therapy should be reserved for those with severe or unresponsive constipation.¹²
• In infants, both sorbitol-containing fruit juice and lactulose are effective and safe alternatives to macrogol, but large doses of lactulose can be associated with cramping. Paraffin oil should be avoided in infants and children in whom aspiration may occur, because of the risk of lipoid pneumonia. Stimulant laxatives (bisacodyl) are also not recommended in this age group because they can cause abdominal pain. Glycerol suppositories are not recommended as they are associated with anal irritation.

Behavioural therapy

• The child should be encouraged to sit on the toilet for five minutes, two or three times daily, ideally within 30 minutes of meals to take advantage of the gastrocolic reflex.
• Positive reinforcement for sitting (e.g. reward charts) should be provided. Children should never be punished for being constipated or incontinent.
• A healthy diet should be encouraged. There is little evidence that increasing fibre is an effective treatment for childhood constipation.⁵
• Adequate water intake to avoid dehydration is important when using osmotic laxatives.⁵
• There is limited evidence that avoiding cow’s milk may result in improvement in some children with chronic constipation, particularly in those with atopic tendencies. Any trial of dairy elimination should be limited to two to four weeks and the child should be rechallenged for confirmation of any significant effect. Prolonged elimination diets require supervision by a dietitian to ensure nutritional deficiencies do not develop.⁵

Long-term management

• Regular review is required to monitor response to therapy, adjust laxative dose, continue education, reinforce the management plan and support the family through what is often a long and frustrating period.
• Failure to respond should prompt review of the management plan including adherence, and may prompt reconsideration of pathological causes and further investigation.

Conclusion

• Constipation is very common in childhood and is usually functional.
• Further investigation and referral is guided by the presence of ‘red flags’.
• A holistic treatment approach including education, behavioural modification and often long-term laxative use is required for successful treatment.
• Long-term use of osmotic laxatives has been shown to be safe and well tolerated in clinical studies.
• Oral macrogol 3350 is the preferred laxative agent; rectal therapy is unnecessary in most cases and is rarely indicated in the primary health care setting.
• If a child fails to respond to standard therapy, adequate dose titration of the prescribed laxative and implementation of behavioural strategies should be confirmed before considering further investigations or referral.

References