NICE vs RCPCH: Management of Constipation in Children (2025)
Constipation is a common paediatric problem in the UK, accounting for approximately 3% of general paediatric outpatient visits and a significant number of GP consultations. For clinicians, two key evidence-based guidelines inform practice: the National Institute for Health and Care Excellence (NICE) Clinical Guideline CG99 [May 2010, last updated December 2023] and the Royal College of Paediatrics and Child Health (RCPCH) Constipation Care Pathway [2021]. While both aim to standardise and improve care, they differ in structure, emphasis, and some practical recommendations. This comparison provides a factual analysis for UK clinicians, highlighting key differences and practical takeaways to support clinical decision-making.
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Diagnosis and Assessment
NICE CG99 Approach
NICE provides a highly structured, criteria-based approach to diagnosis. It emphasises taking a clinical history to identify red flag symptoms that might suggest an underlying organic condition (e.g., Hirschsprung's disease). The diagnosis is primarily based on the presence of specific symptoms.
- Diagnostic Criteria: Diagnosis is made if the child has had 2 or more of the following features for at least 1 month:
- Fewer than 3 complete bowel movements per week.
- Overflow faecal incontinence (soiling) more than once a week.
- Large, infrequent stools that clog the toilet.
- Palpable faecal mass on abdominal examination.
- 'Stool withholding' behaviour.
- Painful defecation.
- Examination: Stresses the importance of abdominal and lower limb examination, including inspection of the perianal area for fissures and fissures. A digital rectal examination (DRE) is not recommended in primary care.
RCPCH Care Pathway Approach
The RCPCH pathway, while acknowledging similar diagnostic features, is presented as a more practical, stepwise algorithm for clinicians. It places a stronger emphasis on the early identification of faecal impaction as a key step before initiating a treatment plan.
- Diagnostic Focus: The pathway quickly guides the clinician to assess for impaction, using a combination of history (e.g., overflow soiling, palpable mass) and physical signs.
- Examination: Similar to NICE, it recommends abdominal examination and inspection of the spine and perianal area. Its stance on DRE is more nuanced, stating it is "not routinely required" but may be considered by specialists if the diagnosis is uncertain.
Key Difference & Practical Takeaway
Difference: NICE is more explicit with formal diagnostic criteria, while RCPCH is more algorithm-driven, focusing on the immediate clinical decision point: "Is the child impacted?".
Takeaway: Both guidelines are complementary. Use the NICE criteria to confirm the diagnosis formally, then immediately apply the RCPCH pathway logic to determine if disimpaction is the first necessary step.
Treatment: Disimpaction and Maintenance
Pharmacological Management
Both guidelines agree on the central role of oral laxatives, with polyethylene glycol (PEG) as the first-line agent. However, there are notable differences in dosing strategies and agent sequencing.
NICE CG99 Recommendations
- First-line: PEG (e.g., Movicol, Laxido) is the first-line treatment for both disimpaction and maintenance.
- Disimpaction: Provides a weight-based dosing table for PEG for disimpaction, with clear daily sachet numbers. Treatment should continue for at least 2 weeks until impaction clears (indicated by passage of soft stool without soiling).
- Second-line: If PEG is not tolerated, a stimulant laxative (e.g., Senna, Sodium picosulfate) is recommended as second-line.
- Stool Softeners: Lactulose is positioned as an alternative if stimulant laxatives are not suitable.
RCPCH Care Pathway Recommendations
- First-line: Strongly advocates for PEG as first-line.
- Disimpaction Dosing: Recommends a more aggressive, weight-based "disimpaction regimen" with higher initial doses of PEG, titrated upwards every 2-3 days until overflow soiling stops. This is a more dynamic approach than NICE's fixed table.
- Combination Therapy: Explicitly suggests that if PEG alone is insufficient for disimpaction, a stimulant laxative (e.g., Senna) can be added to the regimen. This is a key practical divergence.
- Lactulose: Notes that Lactulose is less effective than PEG and is not recommended for disimpaction.
Maintenance Therapy
Both guidelines agree that maintenance therapy should continue for several weeks after regular bowel habits are established. NICE recommends a minimum of 4 weeks, with a gradual dose reduction over months. The RCPCH pathway similarly emphasises long-term maintenance, often for months, to prevent relapse.
Key Difference & Practical Takeaway
Difference: The most significant difference is the RCPCH's endorsement of combination therapy (PEG + Stimulant) for difficult disimpaction and its more aggressive, titrated dosing strategy.
Takeaway: For standard cases, follow NICE's weight-based table. For resistant impaction, adopt the RCPCH approach of titrating the PEG dose upwards and considering the addition of a stimulant laxative for a short period.
Special Situations
Infants under 1 Year
- NICE: Advises greater caution. Treatment should be supervised by a specialist. First-line pharmacological treatment is a stool softener (e.g., Lactulose) or a stimulant laxative. PEG is not licensed for infants under 1 year but can be considered under specialist advice.
- RCPCH: Also recommends specialist involvement. Suggests considering Lactulose or a stimulant laxative. Its pathway directs clinicians to seek senior advice for this age group.
Children with Neurodisabilities
Both guidelines recognise this group as high-risk for chronic, severe constipation. They recommend proactive management and often higher maintenance doses of laxatives. The RCPCH pathway includes specific consideration for this population, emphasising the need for individualised care plans.
Key Difference & Practical Takeaway
Difference: Minor differences in infants, with NICE being slightly more prescriptive on agent choice.
Takeaway: For infants under 1, involve paediatric specialists early. For children with neurodisabilities, anticipate the need for long-term, high-dose maintenance therapy and create a personalised plan.
Practical Clinical Flow for UK Clinicians
Combining the strengths of both guidelines, a suggested pragmatic flow is:
- History & Examination: Use NICE's diagnostic criteria to confirm functional constipation. Elicit red flags. Perform abdominal and perianal inspection.
- Assess for Impaction (RCPCH Focus): Determine if faecal impaction is present based on history (soiling, palpable mass) and examination.
- Disimpaction Phase:
- Start with a weight-based PEG regimen (using NICE table as a starting point).
- If response is inadequate after 3-4 days, titrate the PEG dose upwards (RCPCH strategy) until soiling ceases and soft stool is passed.
- If impaction remains resistant, add a stimulant laxative for 1-2 weeks (RCPCH combination therapy).
- Maintenance Phase: Once disimpacted, continue PEG at a lower maintenance dose. Plan for a minimum of 4-8 weeks of treatment, with a very gradual withdrawal over months, guided by symptom control.
- Non-Pharmacological Support: Throughout treatment, provide dietary and behavioural advice (adequate fluids, fibre, regular toilet sitting after meals).
Frequently Asked Questions (FAQs) for Clinicians
1. Which guideline should I follow primarily?
Use them together. NICE provides the formal diagnostic framework and core evidence base. The RCPCH pathway offers a modern, practical algorithm, especially for managing treatment-resistant cases. The RCPCH pathway can be seen as an operationalisation of the NICE principles.
2. A child is not responding to high-dose PEG. What next?
This is where the RCPCH guidance adds value. First, ensure adherence and that the dose is high enough (titrate upwards). If still no response, follow the RCPCH recommendation to add a stimulant laxative (e.g., Senna) for a short period to achieve disimpaction. Re-check for red flags and consider secondary care referral.
3. How long should maintenance therapy last?
Both guidelines stress that this is often much longer than clinicians and parents anticipate. A minimum of several weeks after symptoms resolve is needed, but many children require months of treatment to prevent relapse. The weaning process should be slow and gradual, over several months.
4. Is Lactulose still a recommended first-line agent?
No. Both guidelines firmly position PEG as superior to Lactulose for efficacy and tolerability. Lactulose is now considered an alternative, mainly for situations where PEG is not tolerated or, in the case of infants, under specialist guidance.
5. When should I refer to paediatric secondary care?
Indications are consistent across both guidelines: presence of red flags (e.g., failure to pass meconium, abnormal thyroid studies, structural anomalies), uncertainty in diagnosis, constipation presenting in the neonatal period, or failure of an adequate trial of treatment (including combination therapy) in primary care.
Source Links
- NICE Guideline CG99 - Constipation in children and young people: diagnosis and management (Last updated Dec 2023): NICE CG99
- RCPCH Constipation Care Pathway (2021): RCPCH constipation care pathway