Constipation in Children
Constipation is a common issue in children, defined as infrequent and/or difficult passage of stools. In over 95% of cases, it is idiopathic or functional, meaning there’s no underlying physical cause. The UK’s National Institute for Health and Care Excellence (NICE) guidelines focus on a practical, stepped approach to diagnosis and management, with a strong emphasis on education and de-escalating any anxiety for the family.
Aetiology and Clinical Assessment
Common Causes
Functional Constipation: This is the most frequent cause, often starting after a painful bowel movement. The child then starts a “holding pattern” to avoid the pain, leading to a vicious cycle of withholding, faecal impaction, and further pain.
Dietary: Low fibre intake and poor fluid intake.
Toilet Training: The start of toilet training or a change in routine (e.g., starting nursery or school) can be a trigger.
Worrying (Organic) Causes
Although rare, organic causes must be considered, particularly in infants or in cases that don’t respond to standard treatment.
Hirschsprung’s Disease: A congenital condition where part of the bowel lacks nerve cells. A red flag is a failure to pass meconium within the first 24-48 hours of life.
Cystic Fibrosis: Meconium ileus in newborns can be a sign.
Endocrine: Hypothyroidism or hypercalcaemia.
Structural: Anal stenosis, strictures, or a rectosacral mass.
History
A detailed history is the most important part of the assessment.
Stool Characteristics: Frequency, consistency (using the Bristol Stool Chart), and if the stools are large enough to block the toilet.
Holding Behaviour: Ask about “holding on,” such as standing on tiptoes, rocking, or hiding.
Soiling: Faecal incontinence (soiling) is a sign of underlying constipation with faecal impaction.
Associated Symptoms: Inquire about abdominal pain, poor appetite, or urinary incontinence, which can be linked to a full rectum pressing on the bladder.
Examination
General: Assess the child’s growth and hydration status.
Abdomen: Palpate gently for a faecal mass, often palpable in the left lower quadrant or across the lower abdomen.
Anus: Inspect the anus for fissures, tags, or signs of past abuse. A rectal examination is generally not recommended in children unless there is a specific concern about an organic cause.
Management
The management of functional constipation is a two-step process: disimpaction (if needed) and maintenance.
Step 1: Disimpaction
This is required if there is a large amount of retained stool.
Macrogols: The first-line medication is a high-dose oral macrogol (e.g., Movicol Paediatric Plain), which works by drawing water into the bowel to soften the faeces. The dose is titrated up until the stools are soft and diarrhoea-like, indicating disimpaction has occurred.
Combination Therapy: If macrogols are ineffective, a stimulant laxative such as sodium picosulfate or senna can be added.
Step 2: Maintenance
This is a long-term strategy to prevent recurrence.
Medication: Oral macrogols (or another laxative like lactulose) are used daily to ensure soft, easy-to-pass stools. The dose is slowly reduced over months as the child gains confidence.
Lifestyle Changes:
Diet: Advise a balanced diet with adequate fibre and fluid intake.
Toileting Habit: Encourage a regular “toileting habit” by having the child sit on the toilet for a few minutes after each meal (or at a set time) to take advantage of the gastro-colic reflex.
Reward Charts: Use reward charts to positively reinforce toileting.
Education: Providing detailed education and reassurance to the family is critical to the success of the management plan.
Referral to a Specialist
Referral to a specialist, such as a paediatric gastroenterologist, is necessary if:
The diagnosis of functional constipation is uncertain.
There are features of an organic cause.
The child is under 12 months with persistent constipation.
The constipation is refractory to standard management.