Pediatric Rectal Prolapse Workup

Updated: Dec 12, 2019
  • Author: Jaime Shalkow, MD, FACS; Chief Editor: Carmen Cuffari, MD  more...
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Workup

Approach Considerations

The primary care physician should initially approach rectal prolapse as a symptom rather than a specific disease entity and should always search for an underlying disorder. Anatomic causes such as Hirschsprung disease and history of imperforate anus repair should be sought. Inquire about a history of constipation, diarrhea, parasitic infections, polyps, or anal stenosis.

High-resolution ultrasonography and magnetic resonance imaging (MRI) provide excellent depiction of the pelvic anatomy and are helpful to illustrate functional changes. Contrast enema, proctosigmoidoscopy, video defecography, anal manometry, electromyography, and anal endosonography may also be useful.

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Laboratory Tests

Sweat chloride test

Since the potentially disastrous consequences of missing the diagnosis of cystic fibrosis, and because of the improved prognosis associated with early diagnosis and institution of treatment, the sweat chloride test is indicated in all patients who present with rectal prolapse without an underlying anatomic abnormality. In the era of newborn screening for cystic fibrosis, 3.6% of patients with rectal prolapse had cystic fibrosis, and conversely, 3.5%, of patients with cystic fibrosis have rectal prolapse. Earlier studies quoted a higher incidence of rectal prolapse in children with cystic fibrosis, often occurring in approximately 20% of cases, usually between 6 months and 3 years of age  [1] .

Stool evaluation for ova and parasites

Rectal prolapse has been associated with Escherichia coli 0157:H7 infection; antibiotic-associated colitis; Entamoeba histolytica infection; and Giardia, Salmonella, Shigella, and Trichuris infection. Consider a workup for other associated illnesses in the appropriate setting as clinically indicated.

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Magnetic Resonance Imaging

Dynamic MRI provides a high resolution, real time integrated structural assessment on morphological and functional display of the pelvic anatomy  [35, 36] . The first reports of MRI in the study of gastrointestinal tract were reported in the late 1980’s and early 1990’s, which assessed gastric emptying  [35] . For children, the advantages of dynamic MRI over other modalities are that it is non-invasive, without exposure to ionizing radiation, provides excellent soft tissue resolution, and allows visualization of the anterior, middle and posterior pelvic compartments. Limitations include the supine positioning and evaluation of defecation under non-physiological conditions [35, 36] .

MRI can be used both for a multicompartmental dynamic assessment of the pelvic floor, which is referred to as dynamic MRI defecography  [37] and for the anatomic analysis of the internal anal sphincter (IAS) and external anal sphincter (EAS), which is referred to as static MRI [38] . The dynamic sequence consist of rest, squeeze, straining (pre rectal filling), and defecation (post rectal filling)  [39] .

Considering MRD versus fluoroscopy, MRD has a better detection rate for structural abnormalities than fluoroscopy  [40] . According to previous studies, fluoroscopic defecography would have been more accurate at identifying enterocele and internal prolapse  [36] .

It must be emphasized, that etiology and natural history of an internal prolapse, especially rectal intussusception, requires special preoperative imaging assessment  [36] . However, there is no evidence to demonstrate that the dMRI abnormalities shown for adults can be interpreted in the same way for children  [35] . Actually, there is no significant advantage of MRD when attempting to detect abnormalities of the anterior or middle compartments, compared to clinical examination. Dvorkin et al. recommended the use of MRD when planning surgery; similarly, Attenberg et al. concluded that MRD did have an impact on treatment strategy decision-making. Kaufman et al. found that MRD had been particularly useful when used in the context of follow-up for patients after pelvic floor reconstruction. Finally, Ramage et. al concluded that MRD with a full evacuatory phase remains as a valid study, forming part of the diagnostic work-up in the management of multi-compartment pelvic floor dysfunction. As well, Li, Jiang, Peng, and Yang, suggest that MR defecography is an excellent tool to better understand the complex anatomy and function of the pelvic floor, aiding the surgeon in preoperative planning and selecting the surgical procedure of choice, specifically in case of multi-compartment problems [39, 40] .

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Contrast Enema

Sigmoid intussusception rarely presents as rectal prolapse in pediatric patients. In 1990, Ashcraft et al highlighted the importance of preoperative diagnosis for prevention of inappropriate initial treatment and postoperative recurrence. [41] In their series of 46 patients, two children required subsequent sigmoid resection. Preoperative contrast enema with a defecating view revealed a coiled-spring appearance typical of sigmoid intussusception. It is also useful in identifying polyps or other leading points.

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Video Defecography

Defecography or video defecography is a dynamic radiologic test performed with contrast during voluntary evacuation of the rectum to asses the anorectal function at rest and during defecation  [37] . Video defecography of the contrast-filled rectum during defecation can be used to identify rectal prolapse or intussusception, or to disclose significant pathology (enterocele, rectocele, sigmoid intussusception) and thereby guide surgical treatment  [42, 43, 44] . It also allows understanding the pathophysiology of defecation disorders in children.

The main indication for defecography on Mugie et al. study was long-lasting severe constipation. Other indications on the same study were intractable fecal incontinence and rectal prolapse  [37] .

The defecography has the advantage of displaying pathological sequences in a simulated defecation in a conscious patient, being a well-tolerated test. Disadvantages include radiation exposure (0.63 mGy to 2.09 mGy), and a considerable false negative rate on rectal prolapse and related disorders (83.3%).  In younger patients, lack of cooperation is another issue  [37] . Koivusalo, Pakarinen, Rintala and Seuri recommended the dynamic defecography in patients 10 years of age or older with atypical symptoms, or if rectal ulcer is suspected. It is considered unnecessary for full thickness rectal prolapse  [45, 46, 47] . Whenever MRI defecography is available it should be preferred instead of fluoroscopic defecography due to its lack of ionizing radiation exposure  [37] .

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Proctosigmoidoscopy

Endoscopic evaluation is useful to rule out polyps in patients with recurring rectal prolapse or history of rectal bleeding. It allows for tissue samples and identifies a leading point in the case of intussusception.

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Other Tests

Anal manometry

The clinical and cost benefits of routine preoperative anal manometry, pudendal nerve motor latency, and colonic transit are unclear. Anal manometry shows low resting pressure; patients with coexisting fecal incontinence also have low squeezing pressures. However, after surgery, the resting pressure or sphincter length may not change or improve. However, squeeze pressure may improve. [46]

Electromyography

Electromyography has provided insights into the pathogenesis of fecal incontinence; however, it has no place in the clinical workup of this entity, and hardly any research has been done so far. Abnormalities can be found in patients with rectal prolapse, but these results do not predict continence after rectopexy. [46]

Anal endosonography

It may show asymmetry and thickening of the internal anal sphincter and submucosa. Demonstration of a sphincteric defect might be useful if a sphincter reconstruction is being considered. [46]

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