Faecal impaction in children aged 0–18 years: a systematic review and metanarrative analysis of definitions used

Abstract

Background

Faecal impaction is the result of functional constipation in the majority of cases. Surprisingly, a uniform definition for the term faecal impaction is lacking, leading to heterogeneity across study results.

Aim

To conduct a metanarrative systematic review to ascertain how trial studies define faecal impaction among children aged 0–18 years with functional constipation.

Methods

We conducted a systematic metanarrative review to uncover what criteria are used to define faecal impaction and to recommend directions for creating a globally accepted definition. A comprehensive literature search was conducted using prominent databases, including CENTRAL, MEDLINE, Embase, WHO ICTR (international clinical trials registry) and ClinicalTrials.gov. All relevant publications of RCTs on both faecal impaction and functional constipation from inception to June 2024, including children aged 0–18 years without underlying organic aetiology, were included.

Results

6211 studies were screened, of which 155 were reviewed for eligibility, 76 were included in the review and five are awaiting classification. Seven studies gave an explicit definition, with three referencing a previous consensus definition. 45 studies gave an implicit definition derived from their prescreening or exclusion criteria in a larger piece of research. Clinical assessment was the most common element of definitions, with a mixture of abdominal or rectal assessments reported in 44 studies. A further six studies suggested such clinical assessments are combined with radiographs, and one study reported a definition using radiographs alone. One study reported the duration of symptoms in a definition.

Conclusion

There is a clear lack of consensus for defining faecal impaction in children with functional constipation. Despite the clinical, diagnostic and prognostic importance of having a unified definition of faecal impaction, currently there seems to be no universally accepted definition.

WHAT IS ALREADY KNOWN ON THIS TOPIC

• Faecal impaction is a common and potentially serious condition among children aged 0–18 years with functional constipation. Nonetheless, an unambiguous definition does not exist.

WHAT THIS STUDY ADDS

• The current literature shows a severe lack of consensus among definitions used in children with faecal impaction. Some studies have included no definition, and almost all implicitly defined faecal impaction.

HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY

• This metanarrative review can lead to recommending directions for creating a globally accepted definition or alternatively discourage the use of the term to describe a standalone clinical paradigm. This clarity will aid in comparing results among studies, coordinating appropriate care and improving the utility of clinical practice guidelines.

Introduction

Functional constipation (FC) is defined by the Rome IV criteria as a disorder of gut–brain interaction.¹ FC is a common clinical entity in children and is associated with a reduced health-related quality of life.² In a systematic review that meta-analysed 33 paediatric studies from around the globe, FC reported a pooled prevalence of 9.5% (95% CI 7.5 to 12.1).³ FC also incurs considerable healthcare costs estimated to be up to $3.9 billion annually.⁴

Faecal impaction is a common problem in children with constipation.^{5 6} Timely identification of the impaction minimises complications and poor outcomes.⁷ Multiple items of the Rome IV criteria for FC refer to faecal impaction. Those include a history of large-diameter stools and the presence of large faecal mass in either the abdomen or the rectum. Additionally, the Rome IV criteria recommend differentiating patients with IBS-C (Irritable bowel syndrome - constipation predominant) from FC, based on the resolution of pain after disimpaction.¹

Overall, there is a gap in the literature for investigating faecal impaction in children with constipation. Some controlled trials and research studies’ protocols specifically call for the inclusion or exclusion of participants with faecal impaction.⁸,¹² However, a clear definition of faecal impaction is seldom explicitly stated. A precise definition is vital to compare results across studies and for understanding treatment success and failures. Despite the clinical, diagnostic and prognostic importance of having a unified definition of faecal impaction, there is no universally accepted definition for faecal impaction.¹³ Previous researchers have attempted to define faecal impaction. In an effort to mitigate this gap, in 2005, the Paris Consensus on Childhood Constipation Terminology (PACCT) group sought to define faecal impaction. They defined it as the accumulation of hard stools in the rectum or colon with the unlikely ability to pass them spontaneously. They also stated that it should be assessed by physical examination or by abdominal radiography when appropriate.¹³ However, this definition has not been widely taken up, and faecal impaction is not specifically recognised as a clinical paradigm within the ROME criteria.¹ It is unclear if this suggests that the issue is unsolved and a definition is outstanding or whether such a clinical standalone paradigm is not appropriate. Randomised controlled trials are the gold standard for research and are subjected to significant ethical, financial and funding scrutiny. As such, understanding how this condition is defined within such studies has the potential to capture the current operational and most detailed definitions used in practice. We conducted a systematic review to unveil what criteria are currently used to define faecal impaction and to recommend directions for creating a globally accepted definition.

Methods

The review adhered to the methodologies outlined in a prospectively registered protocol in PROSPERO (CRD42022371846). The project was exempt from full IRB (Institutional research board) requirements for ethical approval. Patient involvement was not part of the scope of the review.

Literature search

A comprehensive literature search was conducted using prominent databases, including CENTRAL, MEDLINE, Embase, WHO ICTR and ClinicalTrials.gov (online supplemental search strategy). Ages ranging from 0 to 18 years were included in the search. Additional hand searches of all Cochrane systematic reviews on chronic constipation were completed, and all such primary studies were checked to evaluate if any explicit or implicit definition of faecal impaction was reported and included if this was the case. The Meta-Analysis PRISMA 2020 checklist and Reporting Items for Systematic Reviews were followed for reporting.¹⁴

Inclusion criteria

All relevant randomised controlled trials from inception to April 2024 on faecal impaction in children were eligible.

Type of participants

Paediatric patients with faecal impaction or patients with FC between the ages of 0 and 18 years.

Type of intervention

Any interventions, drug dosages or absence of intervention were considered eligible as the specific interventions were not the focus of the review.

Type of outcome

Any outcome measures.

Exclusion criteria

Studies that exclusively focused on adults were excluded. Additionally, studies that were written in another language, opinion papers, commentaries, editorials, secondary evidence and review articles and other non-interventional articles were also not included in the review.

Screening

Titles and abstracts of studies were screened independently by two authors (SB and JS) for eligibility. Full papers containing pertinent information were retrieved and subsequently examined by two authors (AB and SA). A third author (VS or MG) resolved disagreements.

Data extraction

Data extraction was conducted on publications that met inclusion criteria and did not meet the exclusion criteria. The extraction was completed in duplicate by three authors (AB, SB and SA), and disagreements were resolved by a fourth author (MG or VS). Data were extracted using the designated headings:

• Definitions for fecal impaction

• Reference for definition utilized (if applicable)

• Classification of definition as explicit or implicit

• Inclusion criteria

• Exclusion criteria

• Type of study

• Age of inclusion

• Location(s) of study

The extraction process was recorded manually within a database file.

Definition of faecal impaction

Studies were organised based on the designated type of definition: explicit or implicit. A common theme among definitions used was identified.

• Mention of a time frame within the definition

• Reference

• Previous therapy

• Mention of constipation

• Mention of bowel frequency at the time of definition

• Method of clinical assessment

• Terminology used for faecal impaction, including faecaloma, faecal mass and faecalith.

We followed a metanarrative approach, which emphasised the similarities and differences observed among definitions. The execution of this method adhered to the RAMESES (Realist And MEta-narrative Evidence Syntheses: Evolving Standards) publication standards for metanarrative reviews as outlined by Wong et al.¹⁵

Data analysis

The data collection process focused on categorical data. All data are presented in the format of tables and figures. No numerical data were analysed in the review.

Risk of bias assessment

Bias analysis is not applicable, as the included studies’ level of bias does not affect the definition of faecal impaction. This metanarrative review focuses solely on the definition as its exclusive outcome of interest.

Results

A total of 6211 studies were identified in a search conducted in April, 6055 of which were excluded as they did not meet the inclusion criteria for this review. 155 studies were retrieved for eligibility. 74 studies were excluded: wrong population, duplicates, non-interventional studies, missing information to judge inclusion and five studies are awaiting classification (response awaited from authors or translations are unclear). A total of 76 studies (75 full papers and one abstract)^{612 16},⁸⁹ were included for full extraction (figure 1) with details in the online supplemental table 1.

Figure 1. PRISMA flowchart. PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Reports of definitions

Among the 76 studies, 52 studies⁶¹⁶,^{27 29} reported a definition for faecal impaction. Among these, seven studies⁶¹⁶,²¹ provided an explicit definition, while 45 studies²²,²⁷²⁹ offered an implicit one. In total, 24 studies1228 35 40 42 43 50 52 55 60 68 69 71 74 75 79 82,⁸⁹ did not report a definition for faecal impaction. The details of the different aspects of definitions among the studies are provided in figure 2.

Figure 2. Visual summary of the contents of definitions for the included studies in the analysis for faecal impaction in children. Explicit definition;⁶¹⁶,²¹ implicit definition²²,²⁷²⁹ and no definition.1228 35 40 42 43 50 52 55 60 68 69 71 74 75 79 82,⁸⁹.

Terminology for faecal impaction

Faecal impaction was explicitly mentioned in the majority of studies. Four studies^{17 25 47 89} used the term ‘faecal retention’ but none defined or referenced this. In supporting the diagnosis and describing clinical assessment, faecaloma was mentioned in 10 studies and faecal mass in 21.

Out of the seven studies⁶¹⁶,²¹ which provided an explicit definition of faecal impaction, only three studies^{6 18 20} included a reference for the definition. For clinical assessment, two studies^{16 21} included abdominal and rectal examination, one study included abdominal or rectal examination for a mass,²⁰ two studies^{6 17} included both abdominal and rectal examinations along with an abdominal X-ray, one study included abdominal and rectal examinations or abdominal X-ray¹⁹ and one study¹⁸ included a rectal examination and an abdominal X-ray. None of the studies mentioned the duration of the symptoms.

The 45 studies²²,²⁷²⁹ with an implicit definition were reported in the context of constipation trials where faecal impaction had been treated before study entry or was an exclusion criterion, and the description or definition used in that context was recorded. The clinical assessments were more variable than the explicit definitions. Five studies^{22 33 49 70 72} reported an abdominal examination, 15 studies2529 37 38 41 44 47 56 57 61 64,^{67 81} a rectal examination, 21 studies2426 27 30 31 34 36 39 48 51 53 54 58 59 62 63 73 76,^{78 80} both abdominal and rectal examinations, one study⁴⁶ an abdominal X-ray, one study⁴⁵ a rectal examination and an abdominal X-ray and one study²³ both abdominal and rectal examinations along with an abdominal X-ray. Among all reports, only a single study³² reported a timeframe for the symptoms, specifying no defecation for >5 days. No study mentioned prior experience or failure of treatment as an element of a definition.

Discussion

The clinical presentation of faecal impaction is a common complication of constipation in children.⁹⁰ It is important to have a consistent and unambiguous definition to compare results among studies, coordinate appropriate care and improve clinical outcomes.

Based on this metanarrative analysis, it is clear that a uniform definition for faecal impaction among children does not exist. Although the PACCT group sought to mitigate this crucial gap,¹³ still only three studies out of the 76 included in this review referred to this publication,^{6 18 20} and most that did not deviated from it. The prevalence of having definitions at all was an issue, with most of those included being implicit in the context of wider discussion or study of constipation. This juxtaposes with a recent study considering a definition for therapy-resistant constipation, which included fewer studies but had more explicit reports of definitions.⁹¹ It is therefore unclear as to whether the lack of definition reflects an appropriate rejection of faecal impaction as a stand-alone sequelae of constipation, and rather it should be seen as a symptom within childhood constipation, perhaps existing within the context of the aforementioned therapy-resistant constipation.⁹¹

The majority of studies did not specify the duration of past symptoms or the length of time participants had experienced faecal impaction or absence of stooling. Only one study³¹ mentioned the duration of impaction. The previous PACCT definition did not explicitly mention the timing of symptoms but did state it should ‘be unlikely to pass by itself’. It is potentially important to consider time as a factor in order to prevent normal faecal impaction from being diagnosed when stool consistency may be hard, and so the clinical distinction between constipation and impaction may become difficult.

The majority of definitions in the reviewed studies, as detailed above, incorporated core clinical characteristics for assessment. In summary, five studies mentioned conducting abdominal physical examination to detect palpable masses indicative of faecal impaction. For the assessment of hard stools, 15 studies reported performing digital rectal examination to evaluate stool consistency in the rectum. 24 studies included both abdominal and rectal examination.

It is quite surprising to see such frequent reports of rectal examination in children. Notably, just one study avoided this examination to prevent exacerbating the fear associated with defecation. The common use of rectal examination is well recognised historically, and its role in these more recent studies could^{92 93} be related to its importance in infants or newborns not passing faeces, where most guidelines support such an examination in order to demonstrate anatomical anomalies^{94 95} or in Hirschsprung’s disease. Paradoxically, recent guidance⁹⁴ suggests that in older children, this examination is usually reserved for experts and is not routinely used to assess faecal impaction. However, some reports still highlight its importance in a few cases where other methods are ineffective.⁹⁶ Thus, the question of digital rectal examination in the diagnosis of faecal impaction is perhaps the element that is the most controversial, and any definition needs to carefully consider whether to include it. Given the lack of a consensus on whether the entity should even be recognised as a stand-alone clinical paradigm, this would seem to be a further barrier to proposing the use of rectal examination outside of the specific contexts noted.

Finally, x-rays were mentioned in seven studies in varying combinations with clinical assessment. Abdominal X-ray alone was mentioned by one study, rectal examination and abdominal X-ray by two studies and both abdominal and rectal examination with abdominal X-ray by four studies. This finding is interesting as the broader field of disorders of gut–brain interaction has very much moved away from radiographs to diagnose constipation, but exceptions are often made in chronic or difficult cases, such as intractable constipation.⁹⁷ Given that so few studies mentioned this, the use of radiograph appears to not be based on a consensus in the context of faecal impaction, and it is worth noting that where a role may exist, other imaging means such as transabdominal ultrasound may have a role.⁹⁸ It is once again worth reflecting that perhaps the lack of a clear definition or even the clear statement that such a clinical paradigm should not be recognised is allowing a gap in which radiographs are finding a role in practice when this should not be the case. As such, clarifying this definition issue may be key to addressing their role or lack thereof.

This review has several strengths. It involved a meticulous search across numerous databases to gather pertinent literature, encompassing every available paper and abstract addressing faecal impaction in children. The articles selected provided both explicit and implicit definitions, enabling us to thoroughly dissect the components necessary to craft a scientific definition of faecal impaction. The decision not to filter out articles based on the quality of their assessment was made as it was believed it did not influence the definition of faecal impaction, but this may be considered a methodological weakness. A final key limitation is the focus on randomised controlled trials. Searching more broadly could have included more definitions, but when a pilot search was performed using key terms without filtering for trials, very few reports that mentioned the condition gave any form of reference or definition, and so these were not considered.

It is important to establish consensus on a definition for this clinical paradigm. As many aspects of the different definitions given in the literature directly inform the choice of therapeutic goals for patients, professionals and researchers, clarity on these definitions will directly inform such practice. It appears that the use of the term is associated with a lack of consensus on clinical presentations and perhaps more importantly, it uses methods that are not acceptable or even common in current paediatric practice. We believe a single consensus definition is needed to clarify the scope of this paradigm, set realistic goals for disimpaction prior to the maintenance of therapy for constipation and ensure understanding in the context of the broader clinical paradigms of constipation and treatment-resistant constipation.

The author team, having worked with the literature during this review, considered devising a definition to form the basis of further discussions. The team’s initial consensus proposal was:

Faecal impaction in childhood is defined as a prolonged period of passing no stool per rectum, associated with previously hard and difficult to pass stools (with a scale of Bristol 1 or 2) and clinical evidence of hard faeces (eg, palpable abdominal mass).

However, the process of considering this definition has raised a number of issues of concern and consternation. This does not give a specific length of time for symptoms, which is similar to most current publications. However, this risks considering cases of intractable or even untreated constipation that align with the ROME IV criteria as being impacted. It also may have some practical limitations without being explicit on the length of symptoms. There was also discussion regarding how clinical evidence is gathered and whether this should be specified at all in the definition. The role of rectal examination, as an invasive intervention that is clearly controversial as discussed above, was also of concern.

This process highlighted the need for a formal study to reach multistakeholder and multinational agreement on any such definition to ensure clinical validity and utility. It is entirely possible that the outcome of such a process may be to actively discourage the recognition of impaction as a stand-alone clinical entity and in doing so allow clarity on some of the diagnostic aspects of concern. It is therefore suggested that such a process should be as clinically and globally inclusive as possible to clarify this situation.

Conclusion

There is a clear lack of consensus for defining faecal impaction in children with FC. The reports focused on abdominal, rectal or X-ray examination, but with little consensus. Definitions did not consider the duration of impaction symptoms or the presence of other indicator symptoms such as incontinence. Despite the clinical, diagnostic and prognostic importance of having a unified definition of faecal impaction, currently, there is no universally accepted definition, and future work is needed to reach a consensus on this or whether this clinical paradigm should not be recognised as a stand-alone entity but rather as a part of wider constipation.

Data availability statement

Data are available upon reasonable request.