Small-bowel transit scintigraphy in children with paediatric intestinal pseudo-obstruction

Abstract

Objectives and Study: Paediatric intestinal pseudo-obstruction (PIPO) is a severe gastrointestinal (GI) motility disorder characterized by symptoms/signs of intestinal obstruction in the absence of luminal occlusion. The diagnosis relies on the clinical picture and GI function tests, including an objective measure of small intestinal dysmotility. Small bowel scintigraphy is minimally invasive and has potential utility to objectively measure small bowel transit. However, the normal range is vaguely defined in adults and the test has not been validated in children. We aim to evaluate the utility of small bowel scintigraphy in children suspected of GI dysmotility, including PIPO. Methods: Patients undergoing solid and/or liquid gastric emptying studies (GES) for suspected foregut dysmotility (including PIPO) from 2019 to 2021 at Great Ormond Street Hospital (GOSH), UK and Queensland Children's Hospital, Australia, were recruited to a study protocol that extended data acquisition from GES to allow assessment of small intestinal transit (small bowel scintigraphy, SBS). Patients who underwent SBS at GOSH from 2016 to 2018 were also included. A diagnosis of PIPO was confirmed and subtypes classified based on antroduodenal manometry (ADM). Small bowel transit, evaluated based on the percentage of colonic filling at 6 hours, was compared between PIPO and non-PIPO patients. Scintigraphic parameters were assessed and correlated against ADM scores1. Statistical analysis was performed with SPSS and P<0.05 was considered significant. Results: Sixty-three patients were included. Based on clinical and/or ADM criteria, 22 patients were diagnosed with PIPO (40.91% male) and 41 with non-PIPO diagnoses (41.46% male). No difference in sex (P=0.591) and age [median of 7.79 (IQR2.79-11.69) vs 9.83 years (IQR4.30-15.79); P=0.075] between groups was found. SBS was performed with liquid and solid meals in 45 and 26 patients, respectively. Eight patients underwent both liquid and solid SBS. As compared to non-PIPO patients, PIPO patients had a significantly lower median percentage of colonic filling at 6 hours, with both liquid (24.82% vs 82.95%; P=0.001, Figure1A) and solid tests (6.71% vs 64.07%; P=0.016, Figure1C). With liquid meals, colonic filling of ≤54.42% at 6 hours provided a sensitivity of 68.40% and specificity of 80% for a PIPO diagnosis, with the area under the curve (AUC) of 0.762 (P=0.003). For solid meals, colonic filling of ≤26.37% provided a sensitivity and specificity of 83.30% and 80% (AUC=0.825, P=0.018). Small bowel transit in patients with myo-/neuromyopathy was significantly slower than those in patients with neuropathic PIPO, both with liquid (3.99% vs 50.00%; P=0.032, Figure1B) and solid meal (1.50% vs 17.13%; P=0.639, Figure1D). There was significant correlation between small bowel transit and ADM scores, reflecting manometric abnormalities (r=-0.417, P=0.009).# Conclusions: This preliminary study provides promise for the potential utility of SBS as an aid to diagnosis and characterisation of PIPO. Colonic filling with radiotracer at 6 hours of ≤54.42% for liquid meals, and ≤26.37% for solid meals may suggest slow transit of the small bowel. Patients with myopathic features had extremely slow small intestinal transit. Studies in a larger paediatric population and across different ages are required.L6385448402022-07-29 <br />