Colonic and Anorectal Manometry Evaluation in Children with Autism Spectrum Disorder with Intractable Constipation

Background: Functional constipation is common in children with autism spectrum disorder (ASD). Increased behavioral and sensory issues are often blamed for failure of children with ASD to respond to standard medical therapies for constipation. Whether failures to respond to standard medical therapies for constipation in children with ASD are due primarily to functional issues or physiological issues is unknown.

Objectives: Evaluate colonic and anorectal manometry findings in a cohort of children with ASD who failed conventional medical treatment in order to determine whether constipation in these children is associated with impaired intestinal motility.

Methods: A retrospective review of children ages 0-21 years with a diagnosis of ASD who met Rome IV criteria for functional constipation and who completed either colonic or anorectal manometry testing at Nationwide Children’s Hospital was performed. Colonic and anorectal manometry studies were independently reviewed by two blinded pediatric gastroenterologists with formal training in manometry interpretation. Children were excluded if studies were incomplete or unable to be interpreted.

Results: Twenty-eight children with ASD had undergone colonic manometry testing. Three studies were excluded because they were unable to be interpreted. Studies from 25 children (80% male, median age 11 years, range 3-18 years) with ASD and functional constipation were analyzed. Fifteen of 25 studies (60%) were normal. Five studies (20%) showed dysmotility in the sigmoid colon with premature termination of high-amplitude propagating contractions in the descending colon. Five studies (20%) showed more extensive dysmotility involving the descending or more proximal colon. Of the 28 children who underwent colonic manometry testing, 24 children had anorectal manometry also performed. Of the 24 anorectal studies, 18 were performed with anesthesia and 6 were performed without anesthesia. The 18 studies under anesthesia showed that each patient had normal rectal anal inhibitory reflexes. Of the 6 studies that were done without anesthesia, 1 was excluded for an incomplete study, 1 indicated the child had abnormal sensation, and 2 suggested pelvic floor dyssynergia.

Conclusions: Colonic and anorectal manometry revealed that a proportion of children with ASD who have failed standard medical therapy for constipation possess signs of impaired motility. Colonic dysmotility was detected in 40% of the colonic manometry studies. Half of these children had impaired motility of the distal colon that is commonly found in children with chronic constipation due to pelvic floor dysfunction. The other half were found to have more extensive dysmotility of the colon that may have resulted in their constipation and failure to medical therapy. Half of children who were able to complete anorectal manometry without anesthesia displayed findings that impair response to standard laxative therapies. Our findings demonstrate that colonic and anorectal manometry can identify children with ASD who have failed medical therapy for constipation with underlying physiological changes and/or impaired motility. Identifying those with impaired motility helps direct decision making for further medical and/or surgical treatments for constipation in this patient population.