BOSTON — A new noninvasive treatment—transcutaneous electrical stimulation—may relieve symptoms for several months in children with slow transit constipation, Bridget Southwell, Ph.D., said at the Neurogastroenterology and Motility 2006 Joint International Meeting.
Imaging studies showed that slow colonic transit might be an underlying factor in about 60% of 155 children with idiopathic, treatment-resistant constipation. Children with this condition, known as slow transit constipation (STC), show deficits in propagating contractions of the colon, and fail to respond to stimuli that normally activate the gut.
The children in the study who received electrical stimulation were part of a larger group of 155 children with idiopathic, chronic, treatment-resistant constipation seen between 1995 and 2004. Children with known causes of chronic constipation, such as those with metabolic or genetic disorders, Hirschsprung's disease, or palpable fecalomas, were excluded from the study population. All of the subgroup had failed diet, laxative treatment, and behavioral therapy; the effects of constipation infringed upon school and play.
Transcutaneous stimulation using interferential current was applied for 20 minutes three times per week for 3–4 weeks using four surface electrodes, placed in front of and behind the umbilical area. Of the 16 children who received electrical stimulation, 81% showed increased defecation and 94% showed decreased soiling. The effects lasted for 3 months or more after stimulation. Dr. Southwell's work merited an Abstract of Distinction and Young Investigator Travel Award.
“Transcutaneous electrical stimulation was originally developed for bladder disorders. It has been used for more than 20 years so we know it is safe,” Dr. Southwell said in an interview. “We hope stimulation [for constipation] will develop into a technique that can be done in the home. Then it could be used by children anywhere, and also by the elderly. At the moment, it is a technique that must be done by physiotherapists.” Dr. Southwell leads a group in Gut Motility Research at the Murdoch Children's Research Institute, Royal Children's Hospital in Victoria (Australia).
The investigators used 48-hour radioisotope transit studies to follow movement through the colon and document STC. Of 155 studies, 20% showed normal transit, 20% anal retention, and 60% pancolonic slowing. (See these patterns in the illustration.)
Those with normal transit show accumulation in the cecum by 6 hours, radioactivity in the rectum by 30 hours, and no radioactivity by 48 hours because of elimination. Those with anal retention show radioactivity remaining in the rectum for 24–48 hours, whereas children with STC show radioactivity in the transverse or descending colons for 30–48 hours, at which point the rectum is still unreactive.
The researchers also evaluated neuromuscular function in children with STC by using 24-hour colonic manometry, in which a catheter with multiple recording sites spanning the colon is inserted via an appendix stoma to monitor contractions. When the results of 18 children with STC were compared with 8 non-STC children, those with STC had fewer anterior propagating contractions and showed no increase in gut activity upon awakening or after eating—findings consistent with poor contractions in the colon and slow transit constipation.
In another poster at the same meeting, Dr. Southwell's group at the Royal Children's Hospital in Victoria described findings suggesting that innervation of the gut wall may be compromised in STC. They reported lower levels of substance P and vasoactive intestinal peptide in biopsies taken from the right colon of children with STC, compared with constipated children without colonic dysmotility.
'We hope stimulation [for constipation] will develop into a technique that can be done in the home.' DR. SOUTHWELL
In 155 children, scintigraphy studies showed that about 20% had normal transit, 20% had anorectal retention, and 60% had slow colonic transit. Courtesy Dr. Bridget Southwell