A CONSTIPATED TODDLER

The most likely diagnosis is functional constipation. This condition is associated with faecal masses in the lower abdomen. Severe constipation can lead to an anal fissure (and vice versa). This is the likely cause of the bleeding. It may be high up in the anus and therefore not visible on inspection. The soiling is involuntary and due to liquid stool leaking from above the hard stool mass in the rectum. Hirschsprung’s disease should be suspected if meconium has not been passed in the first 24 hours of life. However, in this case, the passage of meconium in utero, the lack of symptoms in the first 2 years of life and the normal weight make that diagnosis unlikely. Furthermore, in Hirschsprung’s disease the rectum is usually empty.

Causes of constipation

• Dietary

• Dehydration

• Anal fissure/stenosis

• Hirschsprung’s disease

• Intestinal obstruction e.g. stricture post-necrotizing enterocolitis

• Spinal cord lesion

• Cystic fibrosis (meconium ileus equivalent)

• Cow’s milk intolerance

• Drugs, e.g. opiates, vincristine, lead poisoning

• Hypothyroidism

• Sexual abuse

No investigations are necessary. Usually, clinical assessment suffices to make the diagnosis. In children who refuse a rectal examination, or if there is doubt about the diagnosis, then an abdominal X-ray is useful to assess the degree of faecal loading. Children with constipation are more likely to get urinary infections. In a 4-year-old with a history of one, nonsevere urinary tract infection, no investigations are required. Dietary advice needs to be given, encouraging a good fluid intake, a daily high-fibre cereal and fruit and vegetables. Star charts may also help. Initial drug treatment consists of an osmotic laxative such as lactulose. If that is ineffective, as in this case, a stimulant laxative such as senna should be added. If the patient remains constipated, a more powerful osmotic laxative such as Movicol can be used as a single agent. The doses of these medications can be titrated to the frequency of bowel actions, with the aim being for the child to open their bowels daily in a pain-free manner without soiling. If the child has pain secondary to an anal fissure, lidocaine ointment should help. Whenever possible, treatment is administered orally. However, in some cases glycerine suppositories or phosphate enemas are required to help disimpact hard stool in the rectum. In very severe cases, a bowel-cleansing solution such as Klean-Prep may be needed, and in extreme cases a manual evacuation may need to be performed in theatre.

 Constipation often starts at the age of 2 years when the child is being toilet-trained. Toilet training may lead to ‘power struggles’ between the child and the family and thus to constipation. In some cases, psychological intervention is helpful.

KEY POINTS

• Functional constipation is very common.

• Investigations are usually unnecessary.

• Initial treatment consists of dietary advice and lactulose.