Constipation

Constipation in children is a very common problem in paediatrics. Most cases of constipation can be described as idiopathic constipation or functional constipation, meaning there is not a significant underlying cause other than simple lifestyle factors. It is important to think about possible secondary causes of constipation, such as Hirschsprung’s disease, cystic fibrosis or hypothyroidism.

 

Presentation

How often someone opens their bowels varies between individuals. This is even more variable in breast-fed babies, which can have as little as one stool a week. Someone opening their bowels daily may be constipated, whereas someone opening their bowels twice a week may not, if that is normal for them.

Typical features in the history and examination that suggest constipation are:

  • Less than 3 stools a week
  • Hard stools that are difficult to pass
  • Rabbit dropping stools
  • Straining and painful passages of stools
  • Abdominal pain
  • Holding an abnormal posture, referred to as retentive posturing
  • Rectal bleeding associated with hard stools
  • Faecal impaction causing overflow soiling, with incontinence of particularly loose smelly stools
  • Hard stools may be palpable in abdomen
  • Loss of the sensation of the need to open the bowels

 

Encopresis

Encopresis is the term for faecal incontinence. This is not considered pathological until 4 years of age. It is usually a sign of chronic constipation where the rectum becomes stretched and looses sensation. Large hard stools remain in the rectum and only loose stools are able to bypass the blockage and leak out, causing soiling.

Other rarer causes of encopresis include:

  • Spina bifida
  • Hirschprung’s disease
  • Cerebral palsy
  • Learning disability
  • Psychosocial stress
  • Abuse

 

Lifestyle Factors

There are a number of lifestyle factors that can contribute to the development and continuation of constipation:

  • Habitually not opening the bowels
  • Low fibre diet
  • Poor fluid intake and dehydration
  • Sedentary lifestyle
  • Psychosocial problems such as a difficult home or school environment (always keep safeguarding in mind)

 

Desensitisation of the Rectum

Often patients develop a habit of not opening their bowels when they need to and ignoring the sensation of a full rectum. Over time they loose the sensation of needing to open their bowels, and they open their bowels even less frequently. They start to retain faeces in their rectum. This leads to faecal impaction, which is where a large, hard stool blocks the rectum. Over time the rectum stretches as it fills with more and more faeces. This leads to further desensitisation of the rectum. The longer this goes on, the more difficult it is to treat the constipation and reverse the problem.

 

Secondary Causes

  • Hirschsprung’s disease
  • Cystic fibrosis (particularly meconium ileus)
  • Hypothyroidism
  • Spinal cord lesions
  • Sexual abuse
  • Intestinal obstruction
  • Anal stenosis
  • Cows milk intolerance

 

Red Flags

Red flags are things in the history or examination that should make you think about serious underlying conditions that may be causing the constipation. These should prompt further investigations and referral to a specialist:

  • Not passing meconium within 48 hours of birth (cystic fibrosis or Hirschsprung’s disease)
  • Neurological signs or symptoms, particularly in the lower limbs (cerebral palsy or spinal cord lesion)
  • Vomiting (intestinal obstruction or Hirschsprung’s disease)
  • Ribbon stool (anal stenosis)
  • Abnormal anus (anal stenosis, inflammatory bowel disease or sexual abuse)
  • Abnormal lower back or buttocks (spina bifida, spinal cord lesion or sacral agenesis)
  • Failure to thrive (coeliac disease, hypothyroidism or safeguarding)
  • Acute severe abdominal pain and bloating (obstruction or intussusception)

 

Complications

  • Pain
  • Reduced sensation
  • Anal fissures
  • Haemorrhoids
  • Overflow and soiling
  • Psychosocial morbidity

 

Management

A diagnosis of idiopathic constipation can be made without investigations, provided red flags are considered. It is important to provide adequate explanation of the diagnosis and management as well as reassure parents about the absence of concerning underlying causes. Explain that treating constipation can be a prolonged process, potentially lasting months.

NICE clinical knowledge summaries recommend:

  • Correct any reversible contributing factors, recommend a high fibre diet and good hydration
  • Start laxatives (movicol is first line)
  • Faecal impaction may require a disimpaction regimen with high doses of laxatives at first
  • Encourage and praise visiting the toilet. This could involve scheduling visits, a bowel diary and star charts.

Laxatives should be continued long term and slowly weaned off as the child develops a normal, regular bowel habit.

 

Last updated August 2019
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