PHOENIX—To treat acute colonic pseudo-obstruction that has failed to respond to supportive therapy, decompressive colonoscopy is more likely than pharmacologic treatment with neostigmine to be a successful next measure, according to a study presented at ACG 2025.
Guideline-based stepwise management for acute colonic pseudo-obstruction (ACPO) starts with supportive therapy. If this approach fails, neostigmine is recommended, followed by decompressive colonoscopy, if necessary, noted investigator Joseph Gunderson, MD, an internal medicine resident (PGY-1) at The University of Texas Southwestern Medical Center, in Dallas. However, Dr. Gunderson said, he and his co-investigators found that “decompressive colonoscopy is the ... more effective first-line intervention in ACPO failing supportive therapy, and its usage may offset the need for further interventions.”
First-Line Neostigmine Versus Colonoscopy
To compare the efficacy of first-line neostigmine with decompressive colonoscopy in ACPO cases after unsuccessful supportive therapy, the investigators retrospectively evaluated 271 cases (217 patients) treated between January 2014 and June 2024 in 33 acute care hospitals (abstract 19). The primary outcomes were non-resolution with supportive therapy and resolution without 30-day recurrence after neostigmine or decompressive colonoscopy.
Precipitating factors for ACPO included electrolyte disturbances in 52% of patients, narcotic use in 42%, sepsis in 41%, and respiratory failure in 37%. Median colonic diameter was 10.8 cm. Supportive therapy included bowel rest, use of prokinetic agents (not including neostigmine), withdrawal of precipitating causes, treatment of underlying etiology, and use of nasogastric or rectal tubular decompression. Resolution was indicated by symptomatic or radiographic improvement of distension or stool passage.
In all 271 cases, some degree of supportive therapy was employed. In 74 cases (27%), there was resolution with supportive therapy, and in 197 (73%) there was no resolution. Of the latter group, 61 cases (31%) involved neostigmine and 108 (55%) involved colonoscopy; other interventions were employed in 28 (14%).
Decompressive colonoscopy led to a higher response rate (76%) than neostigmine (41%).
“We identified several factors that were linked to higher risk of failing supportive therapy,” Dr. Gunderson said, noting Black race (adjusted hazard ratio [HR], 1.39), body mass index of at least 30 kg/m2 (HR, 1.45), and core body temperature less than 36°C (HR, 2.19).
Failure risk was lower, however, if the precipitating etiology included electrolyte disturbance (HR, 0.68).
After adjustments for relevant covariates, the odds of resolution without a recurrence within 30 days were 3.48 with decompressive colonoscopy, with neostigmine as the reference (P<0.001).
Study Limitations
Dr. Gunderson acknowledged study limitations, such as the retrospective nature, which did not enable randomization into specific treatment groups, and small sample sizes compared with what would be expected in a randomized prospective study. “However, the increased efficacy of endoscopic decompression relative to neostigmine was observed on multivariable analysis that was adjusted for relevant possible confounders including age, sex, race, ethnicity, and Charlson Comorbidity Index,” he added.
“We did observe some differences in baseline characteristics among patients treated endoscopically and those treated with neostigmine,” he acknowledged. Patients receiving neostigmine were often younger and more likely to have a history of narcotic use or postoperative state as their precipitating etiologies, with a lower cardiovascular risk disease burden. Endoscopically decompressed patients had more coronary artery disease and congestive heart failure and were older.
“It is unclear whether any of these factors would have played a meaningful role in ACPO resolution, given that more plausible confounders such as bowel diameter were not seen to be significantly different between both groups,” Dr. Gunderson said.
He added that none of the covariates on either the univariate or multivariate analysis exhibited a statistically significant relationship with the main outcome of resolution without 30-day recurrence.
Neostigmine was associated with slightly more colonic perforation (8.2% vs. 1.9%) and operative intervention (16.4% vs. 4.6%), including colectomy and operative decompression. Mortality rates were slightly higher in the neostigmine arm (11.5% vs. 8.3%), and 30-day recurrence rates were slightly higher among patients treated endoscopically (7.4% vs. 3.3%). Adverse events associated with neostigmine specifically included bradycardia (9.8%) and asystole (3.3%).
‘A Favorable Study’
Costas H. Kefalas, MD, MMM, MS-PopH, the president of Akron Digestive Health, in Ohio, moderated the session in which the results were presented and shared his thoughts with Gastroenterology & Endoscopy News. Dr. Kefalas commented that the improved outcomes seen in the retrospective study included higher response rates, less colonic perforation, and a reduced need for surgery. Although mortality rates and 30-day recurrence rates were similar with colonoscopy and neostigmine, he said, the benefits are substantial enough to consider this a “favorable study … adding to the growing literature suggesting that decompressive colonoscopy is more effective and potentially safer than neostigmine treatment for these patients.”
—Caroline Helwick
Dr. Gunderson conducted the research while a medical student at the University of Arizona College of Medicine, in Tucson. Drs. Gunderson and Kefalas reported no relevant financial disclosures.
This article is from the March 2026 print issue.