Paediatrics chapters
Enuresis, encopresis and pica
Bedwetting, soiling and eating non-food things: definitions and age limits, primary versus secondary types, causes, what to look for and test, and treatment from alarms and desmopressin to disimpaction and laxatives.
- Enuresis is repeated wetting after the age at which control is expected (day by about 4, night by about 5-6 years); most is primary nocturnal, runs in families and resolves with time; secondary enuresis suggests UTI, diabetes, stress or constipation.
- Treat after about 6 years with reassurance, bladder habits and the enuresis alarm (best long-term cure), or desmopressin for quick but temporary dryness; imipramine is third-line.
- Encopresis is soiling after 4 years, usually retentive (chronic constipation with overflow): disimpact, then laxatives, diet and toilet sitting after meals; pica is eating non-food items for at least 1 month and leads to lead poisoning, worms and iron deficiency.
On this page
Overview
Control of bladder and bowel develops gradually and depends on maturation, family habits and culture. When a child keeps wetting or soiling well after the usual age, the problem causes shame, family conflict and poor self-esteem. Most cases have no serious disease, but the doctor must look for the few organic causes and give practical, non-punitive treatment. Pica, eating non-food items, is grouped here because it is another common behavioural problem of early childhood with real medical consequences.
Normal development of continence
- Toilet training usually starts after the second birthday; the process takes several months and should not be rushed.
- Daytime dryness is expected by about 4 years, night-time dryness by about 5-6 years.
- By 5 years, about 90-95% of children are nearly dry by day and 80-85% are dry at night (Akbar).
- Bowel movements fall from several a day in early infancy to about one a day by 4 years.
Enuresis
Definition and types
Enuresis is repeated passing of urine into clothes or bed, voluntary or not, after the age at which bladder control should be present.
| Type | Meaning |
|---|---|
| Nocturnal | Wetting during sleep (the commonest form) |
| Diurnal | Daytime wetting |
| Primary | The child has never been reliably dry (about 75-90% of cases) |
| Secondary | Wetting returns after a dry spell (Akbar: a few months; Nelson: at least 6 months) |
| Monosymptomatic | Night wetting only, with no daytime urinary symptoms |
Epidemiology
- Commonest urological problem of childhood.
- Night wetting affects about 15% at 5 years, 7% at 8 years and 1% at 15 years.
- About 15% of affected children become dry each year without treatment.
- Boys are affected more than girls at night; daytime wetting is commoner in girls.
- About 60% wet at night only; the rest wet by day or both.
Causes
- Delayed maturation of the brain's control of the bladder (the main factor in primary enuresis).
- Genetic: family history in about half; some families show autosomal dominant inheritance.
- Deep sleep with a high arousal threshold.
- Nocturnal polyuria: no normal night-time rise in ADH (vasopressin).
- Small or overactive bladder with unstable detrusor contractions.
- Constipation: a loaded rectum presses on the bladder.
- Organic causes: UTI, diabetes mellitus, diabetes insipidus, chronic kidney disease, urinary tract obstruction (posterior urethral valves), spinal dysraphism or tethered cord.
- Sleep problems: snoring and enlarged adenoids (obstructive sleep apnoea).
- Psychological stress (birth of a sibling, family break-up, school problems, abuse) can trigger secondary enuresis.
Primary nocturnal enuresis usually has a family history and no organic cause. Secondary enuresis and day plus night wetting are more likely to have an organic or psychological cause.
Assessment
History
- Pattern: night, day or both; primary or secondary; how often.
- Urinary symptoms: frequency, urgency, dysuria, dribbling, poor stream.
- Polyuria and thirst (diabetes mellitus or insipidus).
- Bowel habit and constipation.
- Snoring and sleep pattern.
- Family history; stresses; previous treatments tried; effect on the child.
Examination
- Height, weight and blood pressure (kidney disease).
- Abdomen for a palpable bladder or faecal masses.
- Lower spine: sacral dimple, hairy patch or other signs of spinal dysraphism; lower limb neurology.
- External genitalia (for example hypospadias).
- Rectal examination if constipation is suspected.
Tests
- Urinalysis for every child: specific gravity, glucose, protein, blood and white cells; send a urine culture if indicated.
- A persistently low specific gravity raises the question of diabetes insipidus or a renal concentrating defect.
- Renal ultrasound and micturating cystourethrogram only in complicated cases: recurrent UTIs, severe voiding problems or abnormal neurology.
Routine imaging is not needed for an otherwise well child with primary monosymptomatic nocturnal enuresis and a normal urinalysis.
Management
General measures (all children)
- Reassure the child and parents: it is common, not the child's fault, and improves with age.
- No punishment or shaming; let the child help change the bed as appropriate for age.
- Fluids mainly earlier in the day; limit drinks in the evening and avoid sugary and caffeine drinks late in the day.
- Pass urine at bedtime; some parents wake the child to void about an hour after sleep.
- Star charts (reward dry nights), bladder training.
- Treat constipation, which alone may cure enuresis.
- Adenoidectomy can cure enuresis in a child with enlarged adenoids and snoring.
- Active treatment is usually not needed under about 6 years because wetting is so common at that age.
Alarm therapy (first-line active treatment)
- A sensor in the underwear triggers a buzzer at the first drops of urine; the child wakes, stops and finishes voiding in the toilet.
- About 70% success after a few months, with a low relapse rate (about 10%).
- Needs motivation from child and family.
Drugs
| Drug | How it works | Key facts |
|---|---|---|
| Desmopressin (synthetic ADH analogue) | Cuts night-time urine production | 0.2 mg at bedtime, increased to 0.4 and then 0.6 mg if needed; works quickly; high relapse when stopped (symptomatic, not curative) |
| Oxybutynin, tolterodine (anticholinergic) | Relax an overactive bladder | For daytime symptoms or treatment-resistant cases; often combined with desmopressin |
| Imipramine (tricyclic) | Reduces wetting frequency | Third-line; rarely used now; high relapse; dangerous in overdose (fatal arrhythmias) |
The enuresis alarm gives the best lasting cure; desmopressin gives the fastest short-term dryness.
Desmopressin controls wetting but does not cure it: about 90% relapse when it is stopped (Nelson). It is usually given for 3-6 months and then tapered.
- Combinations (alarm plus desmopressin, desmopressin plus oxybutynin) help resistant cases.
- If a cause is found (UTI, diabetes, obstruction), treat it first.
Encopresis
Definition
Encopresis is repeated passage of stool into inappropriate places (usually the underwear) by a child aged 4 years or older (or of that developmental age), not due to a medicine or medical disorder.
Types
| Type | Features |
|---|---|
| Retentive (with constipation) | The commonest; the child holds back stool, the rectum stretches, hard stool impacts and soft or liquid stool leaks around it (overflow). Also called psychogenic megacolon |
| Non-retentive | No constipation; uncommon; may reflect oppositional behaviour or other psychiatric problems |
| Continuous (primary) | The child has never gained bowel control; often poor or no training |
| Discontinuous (secondary) | Control was present, then lost, often after stress (separation, illness, new sibling); also toilet phobia |
About 95% of children referred with encopresis have no underlying disease; the usual cause is functional constipation with overflow.
Causes of functional constipation and soiling
- Painful defecation (hard stool, anal fissure) leading to withholding; often after an episode of illness or diarrhoea.
- Low-fibre diet, low fluid intake and too much milk (common in toddlers).
- Harsh or forced toilet training; poor school toilets.
- Slow gut transit (family tendency).
- Stress and sexual abuse must be considered.
Organic causes to exclude
| Condition | Clue |
|---|---|
| Hirschsprung disease | Delayed passage of meconium, constipation from birth, empty rectum, tight sphincter; soiling is unusual |
| Spinal cord lesions (tethered cord, tumour) | Abnormal lower limb reflexes, absent anal wink, sacral hairy tuft or sinus |
| Hypothyroidism | Poor linear growth, bradycardia |
| Hypercalcaemia | Other features of high calcium |
| Anal stenosis | Narrow anus on examination |
| Drugs | Opioids, anticholinergics, some antidepressants |
Retentive encopresis has a rectum full of hard stool; Hirschsprung disease has an empty rectum, onset from birth and usually no soiling.
Assessment
- History: age at toilet training, stool frequency and size (large stools may block the toilet), pain, withholding posture, soiling pattern. Parents may wrongly call the leakage "diarrhoea".
- Examination: growth; abdominal faecal masses (felt in about half); lower limb neurology and spine; rectal examination for tone and a stool-filled rectum.
- Tests only if needed: abdominal X-ray to show retained stool, thyroid tests if suggested by the history; rectal biopsy or anal manometry if Hirschsprung disease is suspected.
Management
Treatment of retentive encopresis takes 6-24 months and has four parts.
- Education: explain how the stretched rectum loses sensation and leaks, so the child is not blamed. Many children cannot smell the soiling.
- Disimpaction (clean-out):
- Enemas (saline or phosphate), suppositories and oral laxatives, or oral polyethylene glycol.
- Mineral oil orally is a slower option (do not give to a child at risk of aspiration: it can cause lipoid pneumonia).
- Phosphate enemas can cause hyperphosphataemia and hypocalcaemia, especially in very young children.
- Maintenance:
- Regular laxatives (osmotic such as polyethylene glycol or lactulose, a lubricant, and sometimes a stimulant) to keep stools soft.
- More fibre and fluid; less milk.
- Behavioural training:
- Sit on the toilet after meals (using the gastrocolic reflex) for 5-10 minutes, several times a day, with feet supported.
- Stool diary; praise and rewards; no punishment.
- Toilet phobia: step-by-step rewarded desensitisation.
- Persistent secondary encopresis may need psychotherapy.
"Clean out, keep soft, sit after meals, praise."
- About 1 in 5 children fail treatment, mainly from poor adherence leading to re-impaction.
- The younger the child when treatment starts, the better the result.
Pica
Definition
Pica is the persistent eating of non-nutritive substances for at least 1 month at an age when this is developmentally inappropriate (generally beyond 18-24 months; mouthing objects is normal in infants).
Substances include mud, soil and clay (geophagia), chalk, plaster, paint chips, hair (trichophagia), paper, ash, coal, burnt matches, soap and stones.
Associations
- Nutritional deficiencies: iron, zinc, calcium (cause or effect is uncertain).
- Malnutrition and hunger.
- Neglect, poor supervision, maternal deprivation, parental separation, child abuse, poverty.
- Intellectual disability, autism and developmental delay.
Complications
| Problem | Example |
|---|---|
| Poisoning | Lead poisoning from paint chips (the most important); hyperkalaemia from burnt match heads |
| Parasites | Toxocara, Ascaris and other soil-borne infections (geophagia) |
| Gut problems | Constipation, ulcers, perforation, obstruction; bezoar (hair ball: trichobezoar) |
| Anaemia | Iron deficiency (both a cause and a result) |
In a toddler with pica, anaemia and abdominal pain or irritability, think of lead poisoning, iron deficiency and worm infestation.
Management
- Often settles on its own, but a combined behavioural, social and medical approach is advised.
- Supervise the child and remove the substances (for example lead-based paint) from the home.
- Treat iron deficiency, worms and lead poisoning.
- Assess for neglect, developmental delay and other mental health problems.
- A trichobezoar may need endoscopic or surgical removal.
Expect: ages for expected day and night continence; primary versus secondary enuresis; family history and maturational delay as the commonest cause; urinalysis as the main test; when to image; enuresis alarm as the most effective long-term treatment; desmopressin action, dose and high relapse; imipramine as third-line with overdose risk; constipation as a treatable cause; encopresis defined after 4 years; retentive type with overflow; Hirschsprung disease as the main differential; clean-out then maintenance laxatives and toilet sitting after meals; pica definition, and its link with lead poisoning, worms and iron deficiency.
Quick revision
- Night dryness expected by about 5-6 years; active treatment usually after 6.
- Primary (never dry) is commonest; secondary suggests UTI, diabetes, stress, constipation.
- Family history in half; about 15% cured each year without treatment.
- Urinalysis for all; imaging only if complicated.
- Alarm: best long-term; desmopressin 0.2-0.6 mg at night: quick, high relapse.
- Encopresis: soiling after 4 years; usually retentive constipation with overflow.
- Disimpact, then laxatives, fibre, toilet sitting after meals, praise; 6-24 months.
- Hirschsprung: delayed meconium, empty rectum, no soiling.
- Pica: non-food eating at least 1 month; lead, Toxocara, iron deficiency, bezoar.
Written by The House Job from standard references (Basis of Paediatrics by Pervez Akbar; Nelson Essentials of Paediatrics).
FAQ
At what age should bedwetting be treated?
Night-time wetting is common up to about 6 years, so younger children usually need only reassurance and simple habits. Active treatment with an alarm or medicine is usually offered after that age.
Is the enuresis alarm better than desmopressin?
For a lasting cure, yes: the alarm works in about 70% with few relapses. Desmopressin works faster and is useful for short-term control, but most children wet again when it is stopped.
Why does a constipated child soil liquid stool?
Hard stool collects and stretches the rectum, so the child stops feeling the urge. Softer stool from above leaks around the impacted mass and out of the anus without the child noticing.
Why is pica dangerous?
Children who eat soil, paint or other non-food items can get lead poisoning, worm infections, iron deficiency and blockage of the gut by hair or other material.