Background: The contrast enema diagnosing Hirschsprung’s disease had a high false-negative rate, meaning that even if Hirschsprung’s disease was suspected, the first contrast enema could not diagnose this disease.

Objective: To examine factors associated with the false-negative contrast enema.

Materials and Methods: Retrospective chart reviews of patients with Hirschsprung’s disease underwent pull-through operations at Siriraj University Hospital between November 2006 and January 2021 were carried out.

Results: The sensitivity of the contrast enema was 82.6%. In the 190 patients with contrast enema, 30 out of 172 (17.4%) had false-negative results. To study the associated factors of false-negative contrast enema, the true-positive contrast enema, which was 142, was compared with a false-negative one, which was 30. The median age of the first contrast enema in the true-positive group was 26.6 days and false-negative group was 23.2 days, which was similar (p=0.581). The locations of the transitional zone in any segments of colon had no effect on false-negative contrast enema except for total colonic aganglionosis (TCA). Receiver operating characteristic (ROC) curves and areas under ROC were performed to assess the optimal cut-off value of the interval of rectal examination/rectal wash out withhold prior to contrast enema to predict false-negative. A higher false-negative rate in patients who discontinued the rectal examination of less than two days before the contrast enema than those with two days or more was found (p=0.125). The discontinued interval of rectal irrigation of less than one day before performing the contrast enema affected higher false-negative rates (p=0.091).

Conclusion: Age and locations of the transitional zone were not associated with false-negative contrast enema except for TCA. Too short, discontinued intervals of rectal examination, of less than two days and/or rectal irrigation of less than one day before contrast enema were associated with higher false-negative rates.

 

Received 7 December 2023 | Revised 8 May 2024 | Accepted 13 May 2024

DOI:10.35755/jmedassocthai.2024.7.14007