The Diagnostic Accuracy of Abdominal X-ray in Childhood Constipation: A Systematic Review of the Literature

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper handles a systematic review of the current literature on the accuracy of abdominal x-ray for diagnosing constipation in children. The paper is clearly written and the systematic is adequately performed.

Although (chronic) constipation is a clinical diagnosis (according to Rome IV criteria), an abdominal x-ray could be of help when symptoms and signs are not presented clearly. Otherwise, it is mostly used in children presenting on the emergency ward with abdominal pain in order to exclude other diagnosis such as small bowel obstruction.

Main comment is that there is not presented a gold standard. So, when are we sure that a child is constipated.  How reliable is physical examination or presented symptoms? And when it is shown that there is fecal load in the colon, in what extend is the child chronic constipated?

From an abdominal x-ray the fecal load of the rectum or the colon can be seen, sometimes from here one could suggest the firmness of the stool, however, it reflects the timely state, not whether it is chronic constipation. As the authors have shown a scoring system may be of help but does not produce a reproducible and reliable test. 

That's actually the same for ultrasonography and even CT-scan or MRI. These visualisation studies show the current fecal load and maybe the consistency of the stool, but it does not correlated with the patient's symptoms. Whereas one patient can get rid of the stool easily or with little help, others can feel constipated and not able to pass stool.

These issues are slightly mentioned in the conclusion, but may have a more clear explanation in the discussion.

 

Author Response

On behalf of all the authors, we highly appreciate your comments and feedback.

1) Reference gold standard. We agree with you regarding the limitations of not having a "gold standard" test to compare with to determine the diagnostic accuracy of the abdominal x-ray; however, currently the Rome IV criteria is used to diagnose functional (chronic) constipation in children. To our knowledge, there are no other tests or criteria to diagnose clinical constipation in children at present. Therefore we are left with using the Rome IV criteria or other definitions of constipation as per the included studies to attempt to determine the diagnostic accuracy of the abdominal x-ray.

2) Faecal loading and radiologic tests. We completely agree with you, the extent of faecal loading and the relation of this with symptoms and temporal association is not understood. A sentence explaining this has been added to the discussion section (highlighted). 

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

Dear authors, 

thank you for submitting your research t our journal. Important data is still missing on this topic, however your systematic review due to a lack of studies.however, based on the available data your analysis I is accurate and it may lead to more studies being carried out in this topic - frequently used, yet underreported. 

Author Response

On behalf of all the authors, we highly appreciate your comments and feedback.

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Authors

Thank you for the work done I think that within the existing limitations (scarce number of works and little consistency) the conclusion you reach is consistent. I think you may value the Leech score more as a methodology to use in these cases
Greetings!

Comments for author File: Comments.pdf

Author Response

On behalf of all the authors, we highly appreciate your comments and feedback.