Reviewed By: Pramod Kerkar, MD, FFARCSI

Person is considered constipated when bowel movements result in passage of small amounts of hard, dry stool, usually fewer than three times a week. Slow transit constipation is characterized by the reduced motility of the large intestine, caused by abnormalities of the enteric nerves. This condition is attributed to disordered colonic function. This type of constipation is intractable and doesn’t easily respond to fibers or laxatives and hence comparatively tough to treat.

What Is Slow Transit Constipation?

Slow transit constipation is characterized by the reduced motility of the large intestine, caused by abnormalities of the enteric nerves. Slow transit constipation has been traditionally classified and considered as a functional disorder. The terminology, slow transit constipation, was first coined in 1986, in a group of women who all displayed slow total gut transit time with a normal colon in addition to a variety of other systemic symptoms. Patients with slow transit constipation represent 15-30% of all constipated patients. It is very common in young women. The reason is not known for this.

The colon is 3 to 5 feet long with layers of muscles lining its wall. The muscle contractions produce movement, which help the stool to pass through the colon and out of the body. Small intestine empties the liquid stool in to the colon. The mechanism of the colon is to pull out water from the stool to make it firm. Peristalsis movements help pushing the stool towards its exit point i.e. the rectum. Once the stool hits the rectum, it starts to distend the rectum developing an urge to defecate. The nerves communicate with muscle fibres by releasing chemical messages via messengers (neurotransmitters). These messages are picked up by special receptors in the muscle tissue. If enough receptors are stimulated, this results in muscular contraction.

Some studies have suggested that children with slow transit constipation have abnormal messengers in the muscular layer of their intestinal walls. These abnormalities include a deficiency of a substance (peptide), which is thought to contribute to peristalsis. Research also indicates that the nerve cells of the bowel may be abnormal in number, position or appearance. The peak age for presentation of constipation is shortly after toilet training, when passage of hard stools can cause pain on defecation, which then triggers holding-on behavior in the child. Due to the painful experience, at the time of the next call to stool, the toddler may try to prevent defecation by contraction of the pelvic floor muscles and anal sphincter. Unless the holding-on behavior is quickly corrected by interventions to soften faeces and prevent further pain, the constipation can very rapidly become severe and chronic.

Symptoms Of Slow Transit Constipation

Slow transit constipation has a spectrum of variable severity. The list of symptoms of slow transit constipation is as follows:

  • Constipation
  • Infrequent bowel movements
  • Soiling that is uncontrollable
  • Poor appetite
  • Nausea
  • Bloated or painful abdomen
  • Passing dry/hard stools
  • Diarrhea (rarely)
  • Hemorrhoids (rarely)
  • Blood in stool (rarely)

Diagnosis Of Slow Transit Constipation

Slow transit constipation can be diagnosed soon after birth. The first bowel motion after birth is called meconium which is a dark gluey substance most of which comprises of mucus that layered and protected the bowel lining while the baby was in utero. If the newborn does not pass the meconium until 24 hours or more after birth, this possibly could lead to further investigate the newborn for slow transit constipation. The diagnosis of STC first involves confirming slow transit of faeces with “marker studies” in which the patient swallows a capsule containing either radiolabelled or opaque numbered markers that show up on ­x-rays taken repeatedly over several days or a week to see if the bowel is distended with excess faeces.

  • Barium enema, a special contrasting liquid is flushed into the bowel via the anus and x-rays are taken.
  • A more specialized diagnosis or confirmation of slow transit constipation should involve one or more of these:
  • Comprehensive assessment by a specialist continence adviser – a child with STC may have a distended abdomen and obvious discomfort.
  • Colonic nuclear transit study (NTS) – the child swallows a radioactive dose. Its passage through the bowels is then tracked over three days.
  • Full thickness laparoscopic biopsy – a small surgical incision is made in three places on the abdomen and samples are taken of the bowel wall to look at the muscles and nerve supply and the messenger molecules. This should not be mistaken for rectal biopsies.

It is very important and crucial to exclude other similar disorders which can mislead the treatment. For example, short-segment Hirschsprung’s disease can be excluded by taking a full-thickness rectal biopsy. A real-time x-ray taken during defecation will help suggest which condition is actually responsible for the constipation.

Treatment Of Slow Transit Constipation

Slow transit constipation can be controlled and the treatment options are following:

Medical management. Medications to improve bowel motility can be given to patients suffering from Slow transit constipation. Stimulant laxatives such a bisacodyl are considered first-line therapy. This can be combined with an osmotic laxative such as lactulose. There is no evidence to suggest that chronic use of such laxatives is harmful. Periodic use of bowel preparation solutions such as polyethylene glycol (Glycoprep®) may be needed.

Surgery. Surgery for treating slow transit constipation is a last resort. Surgery is indicated only in severe cases of Slow transit constipation that have failed other management options. The surgical options include:

Sacral nerve stimulator resulting in alteration of the nervous system of the colon.

Chait tube caecostomy which permits both decompression for the bloated colon (megacolon) and also allows for washout of the colon with water and antegrade enemas.
However, it is not always possible to treat slow transit constipation with surgery as too much of bowel may be affected.

Biofeedback. This is the most effective type of treatment option for slow transit constipation. This is a risk-free approach and has been very effective in the patients with slow transit constipation. The uncontrolled defecation is due to inability to coordinate the abdominal and pelvic floor muscles to evacuate stools. This therapy teaches coordination of abdominal and pelvic muscles, and proper positioning which encourages evacuation. It also helps you form practices to promote regularity. Several trials have shown that this approach is not only efficacious but is superior to other treatment methods of slow transit constipation.

Also Read:

Pramod Kerkar

Written, Edited or Reviewed By:

, MD,FFARCSI

Pain Assist Inc.

Last Modified On: September 27, 2018

This article does not provide medical advice. See disclaimer

Sign Up for Our Newsletter

We'll help you live each day to the healthiest