Hirschsprung's disease affects 1 in 5,000 children — the absence of ganglion cells in the colon causes functional obstruction. It classically presents with delayed meconium (>48hrs in term neonates) but can present later with severe constipation. It requires surgical pull-through procedure. Missing it leads to toxic megacolon.
Spinal cord anomalies (tethered cord, sacral agenesis) can present as chronic constipation with urinary symptoms. A sacral dimple or hairy patch above the natal cleft warrants spinal ultrasound in infants and MRI in older children.
Overflow soiling (encopresis) is misdiagnosed as diarrhoea in up to 30% of cases, leading to antidiarrhoeal treatment that worsens impaction and causes significant harm. The distinguishing feature is that soiling is soft or liquid, occurs around a hard mass, and is involuntary. Always ask about hard stools underlying the soiling.
The Bristol Stool Chart improves parent reporting accuracy and is recommended in NICE CG99. Providing a visual tool at consultation takes 30 seconds and dramatically improves history quality at follow-up visits.
Faecal impaction must be treated with disimpaction (high-dose movicol) BEFORE starting maintenance laxatives. Starting maintenance doses in a loaded child will lead to worsening soiling and treatment failure. NICE CG99 is explicit: disimpact first, then maintain.
The pain-fear cycle explains why functional constipation becomes self-perpetuating. Once a child has experienced painful defecation, withholding becomes a conditioned response. This is why laxatives alone are insufficient — behavioural support (toilet training, reward systems, addressing anxiety) is essential for complete resolution.
Rectal examination should NOT be performed in primary care for paediatric constipation — it is distressing, unnecessary, and potentially harmful. NICE CG99 explicitly states that digital rectal examination should only be performed by specialists when the diagnosis is uncertain. Abdominal palpation is sufficient to detect impaction in most cases.
A sacral dimple above the natal cleft (particularly >5mm deep, with hair, haemangioma, or asymmetric gluteal cleft) warrants urgent spinal ultrasound (under 3 months) or MRI (over 3 months). This is a red flag for spinal dysraphism — missing it leads to irreversible neurological damage.
AXR for constipation has been shown in multiple studies to have poor correlation between radiological faecal loading scores and symptoms, and rarely changes primary care management. NICE CG99 (2010, updated 2017) explicitly advises against routine AXR. Avoiding unnecessary abdominal X-rays protects children from ionising radiation.
Coeliac disease affects 1 in 100 children but is diagnosed in fewer than 1 in 4 of those affected. Constipation is an atypical but recognised presentation. Serological screening with tTG IgA is highly sensitive (95%) and specific (97%) and should be considered in any child with unexplained chronic constipation who fails to respond to laxatives.
Constipation with overflow soiling causes significant psychological harm to children — school exclusion, bullying, and low self-esteem are common consequences. When social and psychological impact is significant, psychological support alongside medical management improves long-term outcomes compared to laxatives alone.
Children under 1 year with constipation have a higher rate of organic pathology than older children and should be reviewed more carefully. Referral to paediatrics for all infants under 1 year who do not respond to initial dietary measures is reasonable.
Macrogol (Movicol) is recommended as first-line by NICE CG99 — it works osmotically, is tasteless, and is well-tolerated. A Cochrane review (2012) found macrogol superior to lactulose for stool frequency and consistency and superior to enemas for quality of life. It is safe for long-term use.
The most common reason for treatment failure is stopping laxatives too early. Families stop when stools normalise, but the rectal muscle has been stretched and needs months of normal function to recover its sensitivity. The relapse rate when laxatives are stopped within 4 weeks of normalisation is ~70%. Counsel families explicitly: this is a marathon, not a sprint.
Behavioural interventions combined with laxatives achieve remission in 60–70% of cases at 12 months versus 50% with laxatives alone. ERIC (Education and Resources for Improving Childhood Continence) provides excellent patient resources at eric.org.uk — signpost families to the website and helpline (0808 169 9949).
School toilet barriers are underappreciated — a 2021 study found 85% of children avoided school toilets at some time due to privacy, hygiene, or bullying concerns. A GP letter to the school requesting accessible, supervised toilet time during the school day is a simple, free intervention that significantly helps.
Constipation is one of the most under-followed conditions in paediatric primary care — families are given laxatives and not reviewed until they re-present with problems. Regular structured follow-up at 4–6 weeks significantly improves remission rates and reduces secondary psychological harm.
The overall prognosis for childhood functional constipation is good — 80% achieve remission by puberty. However 30% have ongoing symptoms into adulthood if undertreated. Early, sustained treatment protects long-term bowel function and quality of life.