Definition of Reliable, Objective Criteria by Abdominal Radiography to Identify Occult Constipation in Children with Lower Urinary Tract Symptoms

Prospective assessment of entrance skin dose and targets for radiation reduction during abdominal plain films in pediatric urology patients

INTRODUCTION

Abdominal radiographs are frequently used for evaluation of bowel and bladder dysfunction in pediatric urology. However, the dose of radiation delivered with each study is estimated from machine settings as opposed to measurement of the true entrance skin dose. In addition, the correlation of radiographic constipation with patient symptoms has been questioned.

OBJECTIVE

To evaluate the practices for obtaining abdominal radiographs and the true entrance skin dose of radiation for each examination in order to identify targets for radiation reduction.

STUDY DESIGN

Pediatric urology patients were prospectively enrolled from June 2022 through June 2023. Dosimeters were attached to the navel to collect entrance skin doses from single view abdominal x-ray. Estimated doses were compared to measured entrance skin dose as well as patient characteristics. Exam parameters were evaluated to identify targets for radiation reduction.

RESULTS

A total of 75 patients were recruited for this study with a median age of 10.0 years (IQR 6-14). Most evaluations were done to assess for bowel and bladder dysfunction (68 exams, 91%). The protocol for exams was not standardized resulting in 27% of patients undergoing a medium or high dose strength and 55% undergoing 1 or more image. The median estimated dose was 0.63 mGy (IQR 0.3-1.2 mGy). The median measured dose was 0.77 mGy (IQR 0.31-2.01 mGy) which was significantly different than the estimations (p < 0.001). The estimated dose, measured dose and estimate error were all found to be positively correlated with patient characteristics including age and body mass index (See Figure). Increasing age and body mass index also showed a higher likelihood of increased dose strength and image acquisition.

DISCUSSION

The measured entrance skin dose of radiation is significantly higher than prior estimates. The measured dose but also the estimate error increased with patient age and size which is likely related to higher settings used for image acquisition as patients age. Standardized protocols using low dose settings and limiting image acquisition to the pelvis may reduce radiation exposure in children with bowel and bladder dysfunction while providing adequate diagnostic data.

CONCLUSION

Radiation dose for abdominal radiographs is higher than previously estimated. Older and larger children received higher doses which may be mediated by increased dose strength and image acquisition. Standardization of protocols could lower radiation exposure.

Scoring system to evaluate meaningful fecal impaction in patients with lower urinary tract dysfunction with simple radiography (KUB)

PURPOSE

The management of bowel bladder disorder (BBD) has only been indicated for subjective constipation without objective evidence. We attempted to highlight the radiological findings in patients with BBD and construct a scoring system to identify patients with BBD prior to treatment.

MATERIALS AND METHODS

Forty-five patients with lower urinary tract dysfunction (LUTD) received polyethylene glycol for 2 months before bladder medication for LUTD. Based on partial response to LUTD following treatment, we divided the patients into LUTD-fecal impaction (FI) and LUTD not attributed to FI (LUTD-NFI) groups. Pre/post-treatment kidney, ureter, and bladder (KUB) were compared with respect to several radiographic parameters. Items with significant changes after treatment were included in the scoring system. The accuracy and inter-rater agreement were also evaluated.

RESULTS

Cecal dilation, descending colon dilation, fecal quality, and overall haziness were found to undergo significant changes after laxative treatment. We assigned 0 to 2 points for each item, with a total score of 8. Receiver operating characteristic curve analysis revealed a cutoff value of 5 between LUTD-FI and LUTD-NFI, with 79% sensitivity and 88% specificity. The scoring system was instructed to six doctors who were unaware of it and was then tested on previous patients, which showed a substantial concordance rate (κ=0.79, p<0.05).

CONCLUSIONS

Fecal scoring system based on KUB was beneficial in identifying children with LUTD attributed to FI. This may provide an opportunity to obtain objective FI data as an alternative to subjective assessment of constipation.

Constipation on abdominal radiograph as potential risk factor for recurrent urinary tract infection development

BACKGROUND

To compare clinical history and measurements of fecal load on abdominal radiography (AR) in the prediction of urinary tract infection (UTI) recurrence in children.

METHODS

We combined data from two multicenter longitudinal studies in which children less than 6 years of age with a first or second UTI were followed for recurrence of UTI. Two radiologists reviewed the scout abdominal radiographs of initial voiding cystourethrograms obtained at enrollment from children at two participating sites and measured stool visible in various parts of the colon. We examined how well clinical variables (e.g., voiding and bowel history, use of laxatives at enrollment) and measurements of fecal load predicted recurrence of UTI within 12 months of enrollment.

RESULTS

One hundred and ninety-two children were included. On univariate analyses, age, vesicoureteral reflux (VUR), cecal diameter, rectal diameter, and total stool length on AR were associated with recurrence of UTI. After controlling for age, the odds of recurrent UTI in children with VUR at baseline was 3.85 (95% CI: 1.62, 9.14) higher than in children without VUR. Recurrent UTI was 2.57 (95% CI: 1.01, 6.55) times more likely in children with cecal diameter > 3.10 cm than children with lower cecal diameters; time to first recurrent UTI was shorter in children with elevated cecal diameters (p = 0.0023).

CONCLUSIONS

Cecal diameter on abdominal radiographs predicts UTI recurrence in children with a previous UTI. However, its accuracy is suboptimal to serve as a screening test. Accordingly, its routine use for this indication is not supported. If cecal diameter on an AR ordered for another indication is > 3.10 cm, then management of constipation could be considered.

Time Course of Treatment for Primary Enuresis With Overactive Bladder

PURPOSE

To characterize the course of treatment for nonmonosymptomatic enuresis with overactive bladder (OAB) in a real clinical setting.

METHODS

Data from 111 OAB patients with moderate to severe enuresis were analyzed. The baseline analysis included a questionnaire, voiding diary, uroflowmetry with postvoid residual urine measurement, and plain abdominal radiography of the kidneys, ureters, and bladder (KUB). Following standard urotherapy for 1 month, anticholinergic medication was administered with or without laxatives. Desmopressin was added if there was a partial response to OAB. Patients were followed every 3 months to evaluate the status of OAB and enuresis. Multivariate analysis was performed to identify predictors associated with the lack of complete response (CR) in enuresis at 12 months.

RESULTS

Following 12 months of treatment, 64% and 88% of patients experienced at least partial response in enuresis and OAB, respectively. Urgency improved more quickly than enuresis, supporting the need to address daytime symptoms before enuresis. Seventy-nine patients (71%) had fecal impaction on KUB and/or subjective constipation. The combination of anticholinergics with either laxatives or desmopressin fared better than anticholinergics alone. Daytime incontinence and anticholinergics- only treatment were associated with a lack of CR during 12 months of treatment.

Conclusions

The data confirmed the validity of addressing OAB before treating enuresis. The results of this study also highlight the need to address fecal impaction. Patients should be counseled about the need for a prolonged course of treatment before starting treatment. Anticholinergics should be accompanied with either desmopressin or laxatives for better control of enuresis.

How to use a plain abdominal radiograph in children with functional defecation disorders

Defecation-related functional gastrointestinal disorders (FGIDs), such as infant dyschezia, functional constipation and functional non-retentive faecal incontinence, as defined by the Rome IV criteria, are common problems in childhood. The symptomatology varies from relatively mild, such as crying before passage of soft stools or infrequent defecation to severe problems with faecal impaction and the daily involuntary loss of faeces in the underwear. Conventional radiography is widely available, relatively cheap and is non-invasive. The drawback however, is radiation exposure. This review describes and evaluates the value of different existing scoring methods to assess faecal loading on an abdominal radiograph with or without the use of radio-opaque markers, to measure colonic transit time, in the diagnosis of these defecation-related FGIDs. Insufficient evidence exists for a diagnostic association between clinical symptoms of functional constipation or functional nonretentive faecal incontinence and faecal loading on an abdominal radiograph. Furthermore, evidence does not support the routine use of colonic transit studies to diagnose functional constipation. Colonic transit time measurement may be considered in discriminating between functional constipation and functional non-retentive faecal incontinence and in patients in which the diagnosis is not clear such as having an unreliable medical history. In children with the suspicion of defecation-related FGIDs, the diagnosis should be made based on the Rome IV criteria.

Diagnosis of constipation does not correlate with trans-abdominal ultrasound of rectal distention

INTRODUCTION

Constipation has been shown to have a significant impact on lower urinary tract symptoms (LUTS) in children, and treatment of constipation in children with bowel bladder dysfunction (BBD) has been shown to improve or completely resolve LUTS in many cases. Recent studies utilizing trans-abdominal ultrasound (US) to assess stool burden have correlated diagnosis of constipation with US appearance of rectal stool. An US scoring tool was published in 2008 to assess stool burden, showing linear correlation with constipation severity by symptom questionnaire in an outpatient pediatric constipation clinic population. We hypothesized that this US scoring tool would correlate with constipation symptoms in our outpatient pediatric urology population.

METHODS

In 2010, our pediatric urology outpatient clinic began administering a previously published validated BBD questionnaire to new toilet-trained patients, containing three questions addressing bowel function. Patients in our clinic undergoing trans-abdominal US of the bladder also have assessment of their stool burden by the previously published US scoring tool. We retrospectively reviewed patient charts beginning in June 2013 who had undergone trans-abdominal US of the bladder, gathering data on the first 100 patients with a complete BBD questionnaire and a completed stool burden US scoring tool.

RESULTS

Chart review of 272 consecutive patients was required to enroll 100 patients with a completed US scoring of stool burden and a completed BBD questionnaire. Of these 272 patients, 225 (82%) had a complete scoring of stool burden during their US examination. BBD questionnaires were complete in 107 of 272 patients (39%). Median patient age was 8.2 years, with 69% of patients being female. The most common diagnosis was incontinence or bladder dysfunction (41%). Only one patient (1%) had constipation as the primary diagnosis for their visit. Linear regression analysis showed no correlation of US score to patient reported frequency of bowel movement, frequency of hard stool, frequency of fecal incontinence, or all three symptoms combined. When investigating the subgroup of patients who had diagnoses of BBD/incontinence, this group was seen to have higher mean symptom scores than the entire cohort as a whole, but US scores were still widely variable and again did not correlate with symptom scores.

CONCLUSION

US examination has previously been shown to correlate with symptom severity for children with chronic constipation in a pediatric constipation clinic setting. However, in a pediatric urology outpatient clinic setting at our institution, US examination did not correlate with patient reported symptoms.

Reviewing definitions of urinary continence in the contemporary spina bifida literature: a call for clarity

BACKGROUND

Urinary continence is a common goal for children with spina bifida and their physicians. However, definitions of urinary continence vary widely across published studies. We systematically assessed the utilization of common definitions of urinary continence in the spina bifida literature.

METHODS

We searched library databases for reports (2000-2012) describing urinary continence outcomes in children with spina bifida. We assessed various patient-level factors such as age, lesion level, surgical history, and use of additional therapies, as well as study-level factors such as study design, country of origin, continence definition(s), and method of data collection.

RESULTS

Of 473 identified articles, 105 met inclusion criteria, comprising a total of 3209 patients. Of these, 1791 patients (56%) were deemed continent by the study authors. Only 60 studies (57%) clearly defined what they considered to be "continent". The most common definition, used in 24% of all reports, was "always dry". There was no association between journal of publication (p = 0.13), publication year (p = 0.86), study size (p = 0.26), or study country (p = 0.43) and likelihood of a continence definition being included in the manuscript.

CONCLUSIONS

The most frequent definition of urinary continence in the spina bifida literature is "always dry". However, definitions were highly variable, and many authors did not define continence at all. Clinicians and researchers alike would be better able to apply research findings toward improving patient care if continence definitions were more explicitly reported and less variable.