Slow transit constipation

The large intestine moves waste along its length to the rectum through rhythmic, muscular contractions of its walls (peristalsis). This activity is controlled by the nerves of the enteric nervous system (ENS).

Slow transit constipation (STC), formerly known as neuronal intestinal dysplasia (NID), is a condition in which movement through the large intestine is reduced because of abnormalities of the enteric nerves. The unusually slow passage of waste leads to chronic problems, such as constipation and uncontrollable soiling. There is no cure, but treatment can help manage the symptoms.

Symptoms#

Symptoms can vary, but may include:

• passing bowel motions infrequently
• constipation
• uncontrollable soiling
• abdominal pains
• nausea
• poor appetite
• blood in the stools
• haemorrhoids

Less commonly, some children experience diarrhoea.

STC can sometimes be recognised soon after birth. The first bowel motion after birth is not true faeces but a dark, gluey substance known as meconium, which is mostly the mucus that lined and protected the bowel while the baby was in the womb. A newborn with STC may not pass meconium until 24 hours or more after birth, and this delay may prompt doctors to investigate further.

What causes STC#

STC is a neuromuscular problem. Nerves communicate with muscle fibres by releasing chemical messages called neurotransmitters, which are picked up by special receptors in the muscle tissue. If enough receptors are stimulated, the muscle contracts.

Some studies suggest that children with STC have abnormal neurotransmitters in the muscular layer of their intestinal walls. These include a deficiency of a peptide known as substance P, which is thought to help drive peristalsis. Research also indicates that the nerve cells of the bowel may be abnormal in number, position or appearance.

Effect on quality of life#

Quality of life can be severely affected. Many children with STC have emotional and behavioural difficulties, which may include:

• constant anxiety about losing control of their bowels in public
• fear and embarrassment about their condition
• withdrawal from social situations
• depression and loss of self-esteem, especially if they are teased by other children

STC and Hirschsprung’s disease#

Hirschsprung’s disease is marked by a congenital lack of nerve cells in the rectum, large intestine or both. This means peristalsis is absent in the affected area, so waste stalls and cannot be expelled through the anus, causing severe constipation and obstruction.

This disease is similar in many ways to STC, which can make diagnosis difficult. STC and Hirschsprung’s disease also quite often occur together.

Diagnosis#

STC is often missed because the standard tests used for constipation may not detect it. These standard tests include:

• an x-ray, to see if the bowel is distended with excess faeces
• a barium enema, in which a special contrast liquid is flushed into the bowel via the anus before x-rays are taken

A more specialised diagnosis or confirmation of STC may involve one or more of:

• a comprehensive assessment by a specialist continence adviser
• a colonic nuclear transit study, in which the child swallows a radioactive dose that is tracked through the bowel over about three days
• a full-thickness laparoscopic biopsy, in which small incisions are made in the abdomen and samples of the bowel wall are taken to examine the muscles, nerve supply and messenger molecules

This full-thickness biopsy should not be mistaken for a rectal biopsy.

Treatment#

There is no cure for slow transit constipation. Treatment options may include:

• medication to improve bowel motility
• regular enemas to flush the rectum of faeces
• interferential electrical stimulation therapy, which is painless and often increases bowel motility, improves bowel emptying and reduces the need for medication, washouts or surgery

For some families, symptoms may be so severe that surgical options need to be considered.

Surgery#

The type of surgery chosen depends on the location and extent of the affected bowel, and on the child’s health and age. Options include:

• A colostomy, where the bowel is re-routed through an artificial opening in the abdominal wall and a colostomy bag is fitted. Sometimes a temporary colostomy is performed.
• Bringing the appendix to the surface to create a tiny stoma (opening), which can be done with a laparoscope (telescopic surgery). Enemas can then be given regularly directly into the stoma or appendix.

It is not always possible to treat STC with surgery, as too much of the bowel may be affected.

Helping your child cope#

Strategies that may help your child cope with STC include:

• Never chastise your child for soiling. Remember that their bowels are difficult to control.
• Offer pull-up disposable nappies or other continence aids appropriate to your child’s age.
• Allow your child to talk about their feelings.
• Educate your child about STC so they understand their bowel control problems are not their fault.
• Devise an action plan with your child’s school that includes a trusted teacher’s cooperation at toilet time and easy access to toilets and a shower.
• Join a support group or contact a specialist STC clinic.
• Consider professional counselling for the child and family members, which may be helpful.

Key points#

• Slow transit constipation is caused by abnormalities of the enteric nerves and leads to constipation and uncontrollable soiling.
• It is a neuromuscular problem that can sometimes be recognised soon after birth and may mimic or coincide with Hirschsprung’s disease.
• For some families, symptoms may be so severe that surgical options need to be considered.
• Treatment options include electrical stimulation, medication and surgery.

Where to get help#