History and exam

Key diagnostic factors

common

presence of risk factors

Key risk factors include low fibre intake, poor-nutrient diet, genetic predisposition, infection, stress, obesity, or low birth weight.

difficult or painful defecation

History typically reveals onset of painful defecation with straining and increasing delays from one stool to the next.

long interval between stools

Generally, the increased number of days between stools indicates worsening severity of constipation. However, in older children stool impacting the megarectum may never pass without medical assistance.

faecal incontinence

Faecal incontinence may remit after a large stool is passed. Continuous incontinence, especially occurring during the night, suggests severe megarectum, or rarely spinal cord abnormalities.

small-volume, soft, incontinent stool

Overflow faecal incontinence is usually small and frequent during the day, and consists of soft/loose stool as compared with normal stool consistency in non-retentive faecal incontinence.

palpable faecal mass per abdomen

Central mass that arises from pelvis to a variable distance, often above umbilicus and sometimes as high as the rib margin, indicates impaction and implies the size of the megarectum. This may be difficult to palpate depending on the child’s body habitus.

otherwise healthy child

Children with functional chronic constipation are usually otherwise healthy and have normal growth.

Other diagnostic factors

common

abdominal pain

Abdominal pain is frequently reported accompanying constipation. Organic causes for constipation should also be considered in the diagnosis, and irritable bowel syndrome may often accompany constipation. In these cases, pain may not improve despite the stool burden being passed.[15]

abdominal distention

Inspection of the abdomen often reveals mild or lower abdominal distention from either the loading of the megarectum or large bladder as evidence of lavatory avoidance.

Severe abdominal distention may be a red flag sign suggesting an underlying aetiology, including Hirschsprung's disease.[15][30]​​

uncommon

anal fissure

At any age the anus may show evidence of anal fissure as a cause of painful defecation. Fissures may be acute or chronic. They may be visible at the anal margin (external fissures) but sometimes they may be internal and visible only by endoscopic retroflexion in the rectum.

associated bladder problems

May indicate a neuropathic or myopathic cause for constipation, or faecal and urinary incontinence. A large faecal mass in the rectum may also exert bladder pressure, leading to urgency and/or enuresis. A history of worsening enuresis and encopresis may signal a spinal cord abnormality such as tethered cord.

abnormal anal appearance

A widely dilated anus on inspection may indicate a neuropathic cause. It may indicate poor development of the sphincter (i.e., anorectal anomalies) or, if dynamically dilating (i.e., reflex anal dilation), child sexual abuse must be considered unless there is gross faecal loading of the rectum at time of inspection. Examination should be repeated when the rectum is empty. The position of the anus is important; an anterior anal opening is more common in females and may cause constipation. Imperforate or stenotic anus should be identified by careful examination.

Risk factors

strong

low-fibre diet

Case control studies have shown an association between low dietary fibre and constipation.[25]

poor-nutrient diet

Constipated children have been shown to have a lower caloric and nutrient intake.[25] Excessive milk intake may be a contributing factor.

genetic predisposition

The tendency to develop constipation seems to be familial, with a positive family history in nearly half of all severe cases.[17]

Anecdotal evidence suggests that identical twins seem to have a similar severity of constipation, whereas non-identical twins have the condition to a different degree.

infection

Perianal group A streptococcal infection was found to be a strong precipitator in a small, but easily treated, subgroup of children with constipation.[18]

Urinary tract infection has been reported to have a consistent incidence frequency of 11% in chronically constipated children.[26]

stress

Initial onset or relapse of constipation is frequently reported by parents to occur in association with childhood stress.

The association with stress is even stronger for non-retentive faecal incontinence.

Examples include coercive potty-training, bullying or teasing at school, bereavement, and abuse.

Stressful life events, including sexual abuse, are significantly higher in children with functional defecation disorders compared with healthy children.[27]

obesity

Constipation and soiling are more prevalent in obese children.[28]

low birth weight

One study found a higher incidence of constipation among children with birth weight under 750 g associated with neurodevelopmental impairment.[29]

psychiatric history

Some studies have shown an association between ADHD and constipation as well as other conditions such as autism spectrum disorder and developmental delay.[2][3]​​​​[30][31]​​​​

physical disability

Children with physical disabilities such as cerebral palsy are at increased risk of severe constipation due to impaired mobility.[30]

poor toilet training

Inadequate toilet training between the ages of 1 and 2 years old or a delay in toilet training increases likelihood of stool withholding behaviour, pain while passing stools, and infrequent bowel movements. This increases risk of constipation later in childhood.[32][31]​​

weak

immune dysregulation

There are a few cases where a food intolerance (particularly cows’ milk allergy) leads to eosinophilic proctitis and subsequent discomfort on defecation, causing constipation.[19][20][21]​ Some foods, particularly cows' milk products, may lead to constipation without the demonstration of an allergic mechanism but rather a sensitivity leading to constipation. There is a subset of patients who have improvement in constipation with removal of dairy from the diet.

low fluid intake

While physicians generally recommend increasing the amount and type of fluid intake in children with simple constipation, there is no evidence that this is any more effective than regular fluid intake.[33]

trauma

Accidental direct trauma to the anus is unusual, and any evidence of trauma must lead to the suspicion of child sexual abuse.[22]

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