Constipation and Hirschsprung’s disease

Afzal NA – Clinical Research Fellow & Honorary Specialist Registrar in Paediatric Gastroenterology
University College of London, Royal Free & Chelsae and Westminister Hospitals

Thomson MA – Consultant Paediatric Gastroenterologist and Honorary Senior Lecturer
Royal Free Hospital and University College of London

Normal bowel patterns are very variable in children of all age groups. Weaver and Steiner have shown that 85% of 1 to 4 year olds pass stools once or twice a day and 96% do so three times per day to once every other day.1 When there is delay in defaecation with difficulty or distress, the child is said to suffer from constipation.1 Constipation has also been defined as passing less than 3 stools per week. A child is also said to be suffering from constipation if he or she has painful bowel movements (due to hard or large stools) and stool retention in spite of passing stools more than 3 times per week.2

Constipation is a common problem. It is said to account for 3% of all visits to a paediatric practice and 25% to a paediatric gastroenterology clinic.3,4 The percentage of children suffering from constipation is said to vary from 0.3 to 8% according to different studies.3 The male female ratio is 1: 1 in young constipated children.3 There is a male pre-dominance in children > 5 years old with a reported ratio of 3-6:1.3 At follow up, twice as many boys than girls had soiling and 1.8 times girls than boys were still constipated despite receiving laxatives.3

Presentation

97% of the children presenting with constipation are said to show stool-withholding manoeuvres e.g. crossing their legs or sitting up on their heels. Painful bowel movements have been shown to be present in 77-86% often associated with screaming and only 58% with infrequent bowel movements.3 A rectal/ abdominal stool mass is palpable on deep abdominal palpation in 66-77%.3,5 Hence, if the diagnosis of constipation were just based on infrequent bowel habit, the diagnosis would be missed in almost half of the children with constipation. Recurring UTI may be present in 3.7-30%.3,6

constapation-in-children

Management

The following aspects should be covered in management of constipation in children:

1. Aetiology

2. Education and Behavioural therapy

3. Diet

4. Laxatives

A. Initial Evacuation

B. Maintenance treatment

C. Monitoring

5. Special Cases

1. Aetiology

Organic causes are rare and account for < 10% of constipation in children even in secondary or tertiary referral centres.2,3 Hence the number of children seen in a general practice with organic constipation is even lower.

Symptoms and signs in Table 1 (see appendix) should prompt a practitioner in the community to refer the child to a paediatrician with an interest in gastroenterology/ paediatric gastroenterological unit.

Idiopathic constipation commonly starts after a specific identifiable trigger. A viral infection may result in decreased intake of liquids. Stools become solid causing the child to strain and passage of hard faeces may result in an anal fissure. Defaecation becomes painful which starts a negative cycle, leading to retention of stools. Other common triggers are unavailability of toilet on holiday/camping, school restrictions, teasing by classmates, and access to a smelly facility or sharing the same toilet with several family members.4

Hirschsprung’s disease is commonly considered in any child with chronic constipation. However, it has been shown that if the age at onset of constipation is after the neonatal period, Hirschsprung’s is an extremely unlikely diagnosis.7

Cow’s milk allergy may be aetiological in up to 40% of chronic constipation.8 Strong history of atopy in the individual/family, low IgA, history of gastro-oesophageal reflux refractory to treatment, blood in stool and recurrent viral infections in early childhood may be suggestive of such a diagnosis.9 The appropriate treatment would be removal of the offending agent from the diet and in children less than 2 years of age, substitution with a casein or whey hydrolysate such as Prejestimil, Nutramigen and Peptijunior rather than soya is recommended (Soya displays upto 50% cross reactivity with cow’s milk protein). After two years of age, soya might be needed because of its superior palatability over hydrolysate milks. In such cases, rice based milks supplemented with calcium is also a useful alternative. Such cases could be referred to a paediatrician with interest/ gastroenterologist for diagnosis and management.

2. Education + Behaviour therapy 10

A confirmatory diagnosis with a detailed explanation to the parent is vital for successful future treatment. Abdominal X Ray, if done, may be used to explain the problem. If the child is old enough, he or she should take an active part in the consultation.

Soiling leads to frustration in parents and they often feel that the child is doing it deliberately. Chronic constipation can lead to a mega-rectum (enlarged rectum) with decreased feeling for the presence of stool and hence defaecatory stimulus due to persistent distension. It is vital that parents understand that this is not a deliberate act. Negativity from the parents can worsen the problem.

Some parents stop medication as they find that once the stool becomes loose the discomfort still persists. Lack of compliance due to a whole variety of reasons is common. It is again vital that parents understand the importance of regular maintenance treatment.

Children should not hurry when sitting on the toilet. They should ideally sit on the toilet post-breakfast to allow the gastro-colic reflex to prompt defaecation. Foot support to assist in hip flexion using a children’s toilet seat may be helpful. A diary should be kept for record of stool passage and a reward system should be used. This should be reinforced every time the medical practitioner sees the child.4

Abnormal defaecation dynamics have been observed in 25-50% of children with constipation. Biofeedback training has been used. However, when compared with conventional drug treatment of constipation, biofeedback does not show better long-term recovery in children.5 Moreover, this technique is only usable in an older child and is, to some extent, invasive.

3. Diet

29-48% are found to be ‘fussy eaters’ and 16-47% are described to have a poor appetite. Usually eating improves once the constipation is treated.11

Increased intake of fluids with absorbable and non-absorbable carbohydrate helps to soften the stools. Carbohydrates (especially sorbitol in prune, pear and apple juices) can cause increased frequency and water content of stools.4 A balanced diet with whole grains, fruits and vegetables is recommended. There are no Randomised Controlled Trials (RCTs) to prove that these measures are helpful, though it has been shown that reduced fibre intake is more prevalent among constipated children. Forceful implementation of diet leading to confrontation around meal times should be discouraged.4

4. Laxatives

Laxatives can be divided into four groups based on their mechanism of action.

1. Bulk forming laxatives, which increase faecal mass and stimulate peristalsis (Methyl cellulose, Ispaghula)

2. Stimulant laxatives, (Docusate, Senna, Picosulphate) which increase intestinal motility

3. Faecal softeners (Liquid Paraffin) whose action is mainly to lubricate and soften the stool probably by lining colonic pits and preventing colonic water re-absorption. It is also a mild stimulant.

4. Osmotic laxatives (Magnesium salts, Lactulose, Polyethylene Glycol, Phosphate Enemas), which keep fluids in the bowel by osmosis or by changing the pattern of water distribution in the faeces.

A – Initial Evacuation (See Algorithm)

The stools should be softened before a stimulant is used. Otherwise contraction of bowel against a hard immobile stool may cause severe abdominal cramps and produce no result. Lactulose is usually the first laxative prescribed and a high dose may achieve an evacuation in mild cases with the slight drawback of colonic gas accumulation. If unsuccessful, a dose of sodium picosulphate 6five days later usually achieves evacuation, which may be repeated if necessary. There are no RCTs to support efficacy, though studies of bowel preparation in adults show picosulphate to be more tolerable than ethylene glycol and as effective.13 Sodium picosulphate (for school-aged children) should be used on Friday/Saturday evenings to avoid accidents at school on the following day.

If the above regimen fails we recommend regular paraffin oil 6,14,15, and if needed a dose of sodium picosulphate may be given on the 5th day to achieve complete evacuation.6 In some instances, especially recto-sigmoid faecal impaction, enemas may be needed.6 Hospitalisation may also be needed for refractory cases in order to have NG administration of non-absorbed poly-ethylene glycol (PEG) solution until clear faecal effluent is achieved 13,16or for rectal evacuation under anaesthetic. Recently, Movicol (Polyethylene Glycol sachets) has been used with success, though its use is still unlicensed in children.13 If there is relapse of symptoms, evacuation may need to be repeated.

There are no RCTs to show efficacy of drugs like Senna, bisacodyl etc but they have been used with success.

B – Maintenance treatment (See Algorithm)

An effective approach is to use an osmotic laxative and add a stimulant after a few days, if needed. The commonest osmotic laxative used is lactulose and stimulant is docusate.17 There are no RCTs to show effectiveness of docusate, but we have found it useful in our clinical practice. Senna is effective and may be used where docusate fails, though the trend now in most paediatric centres is to avoid prolonged use due to its side effect profile.3,6,14,17,18,19,20

In severe constipation, paraffin oil and where necessary sodium picosulphate on Friday and Saturday evenings is very effective.6 Paraffin has been shown to be more effective than long-term usage of Senna.14 Lipoid pneumonia and fat-soluble vitamin deficiency has not been found to be a problem,15 the latter is a popular misconception and is based on a single small case series with flawed methods and conclusions from 1935 and this myth has subsequently been dismissed. There have been two cases reported with lipoid pneumonia in the last 20 years in the literature, though we have not come across any in our clinical practice. If needed, pro-kinetics have been shown to be a useful adjunctive treatment. Recently Movicol, though unlicensed, has been used for maintenance treatment in children13 with promising results shown by adult studies.21,22,23 Regular enemas or suppositories are to be strongly discouraged.4

We use “scheriproct – hydrocortisone topical cream” for anal fissures which is better than lignocaine jelly.24 Glyceryl trinitrate (0.2-1%) or isosorbide dinitrate paste have also been used for anal fissures with good success.25 Peri-anal streptococcal infection is rare and, if present, a penicillin is used for treatment.11

C – Monitoring treatment

The key to successful treatment is proper evacuation with appropriate maintenance therapy. The medication doses have to be increased or decreased according to each individual’s requirement. It is important that the doses should not fluctuate too often e.g.: using a dose of 5 mls one day and then 30 mls the next day and then going to 15 mls on third day. The dose change should be planned and gradual.

Diarrhoea with laxative treatment does not automatically mean too much dose. It may often be a sign of overflow i.e. inadequate treatment. In such a case the appropriate treatment would be to increase the dosage with probably a repeat evacuation. Judicious use of abdominal X Ray may allow differentiation.6

Follow up should be frequent initially and if possible should be done by the same practitioner otherwise the child/parent/doctor team begins to fragment.

Most parents often ask – ‘when to stop the treatment?’ Unfortunately there is no single answer. Common practice is to aim for one bowel movement per day on constant dosage. Subsequently after a period of months rather than weeks gradual decrease in dosage of laxatives may be initiated in very small steps. We use an arbitrary figure of 3 months. One needs to be aware that this may be accompanied by re-emergence of symptoms.

5. Special Cases

Management of constipation can be a challenge in children with neuro-developmental problems. In addition these children may have a poor diet low in roughage and fluids. They may have undiagnosed and untreated gastro-oesophageal reflux and gastrointestinal dysmotility. These factors make management difficult. Such cases may be referred to a paediatric centre with an interest in gastroenterology.

It should be remembered that breast fed children have a wider variety of stool frequency, however they may also suffer from cow’s milk protein associated colonic dysmotility if the mother is taking dairy produce and often cow’s milk protein exclusion is useful in such constipated infants.8,9

Prognosis

Factors associated with poor response to acute evacuation of constipation after 1 week of presentation in the emergency department are: female sex; history of recurrent abdominal pain; duration of primary presenting symptom longer than 2 days and history of previous medical visits for the same symptom. There is no difference in outcome based upon treatment.26

In children with chronic constipation, 50% will be cured after 1 year and 65-70% after 2 years 2. Two studies show 34 – 37% still to be constipated, receiving laxatives or soiling 3 to 12 years after start of treatment.3,6

Constipated children < 2 years of age at presentation, respond better to treatment than children > 2 years of age.3 Treatment should be given early to prevent development of severe constipation or faecal soiling or both.11

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