Key Concept: History and physical examination guide most of the evaluation, with ancillary testing used mostly for directed findings, difficult cases, or those who have nonresponsive severe constipation.

Functional constipation is the underlying reason in more than 95 % of children [39], with the diagnosis confirmed by having two or more of the symptoms listed in Table 27.1 [38]. A thorough history and physical examination is typically sufficient to rule out most pathological causes, and extensive additional testing prior to medical and dietary treatment is unnecessary (Table 27.2) [38]. Similar to adults, a comprehensive history should include the frequency and character of the stools, withholding behavior, timing of incontinence, straining, and pain with defecation. Children who present with constipation under 6 months of age, especially who have delayed passage of meconium greater than 48 h after birth, or those who present with abdominal distention and refusal to feed are concerning symptoms for Hirschsprung’s disease, anal stenosis, or ectopic anus (Table 27.3) [35, 39]. Other concerning symptoms that should prompt you to consider a more extensive workup are accompanying urinary tract infections, weight loss, neuromuscular development, and psychological or behavioral problems (Table 27.2) [39].

In addition to a complete abdominal and perineal examination, differences in the examination for pediatric patients should involve looking for other signs of congenital syndrome anomalies (i.e., VACTERL) and ensure there is fecal impaction or anal stenosis [13]. A fecal mass either found in the abdomen or rectum is present in 30–70 % of children with constipation [16]. Investigations for children may include a basic metabolic panel to exclude electrolyte imbalance and thyroid or celiac panels to work up patients with severe unremitting constipation. You should note that most laboratory investigations rarely uncover an underlying disease [35, 38]. Plain abdominal x-rays are seldom helpful to assess fecal retention, and actually correlate poorly between symptoms and pathology, leaving more open to misinterpretation [39, 40]. For children over 12 months of age, anorectal manometry can be extremely valuable when Hirschsprung’s disease is in the differential diagnosis. Failure of relaxation of the internal sphincter is an absolute indication for rectal biopsy and has a high positive predictive value for the absence of ganglion cells [35]. Furthermore, in any infant or other patient in whom Hirschsprung’s disease is suggested, a rectal biopsy is the gold standard for diagnosis. You should remember that short-segment Hirschsprung’s disease may manifest later in childhood (or even adult life) with constipation, and work up those select patients accordingly. While ultrasound has been suggested to look at fecal load in the colon, it really is not very useful. This is similar to the colon transit studies, where some authors feel it is helpful [37]. One could argue that in children with normal transit time, surgery is not typically indicated [41]. Others suggest it aids in determining the point at which normal peristalsis is lost [39, 42]. However, we rarely find it useful in the primary workup for constipation. Finally, though the indication for endoscopy for primary constipation symptoms is rare, high-risk or concerning symptoms should direct the need accordingly.

Key Concept: Use medical management and dietary changes as first–line therapy—they will work most of the time.

Years of experience and expert opinion guide most of constipation management. We find that the most useful first step is often helping the patient and family to understand the problem and enlist their cooperation and compliance in what is often a trial and error period [36, 38]. Interestingly, there is an association between not only low-fiber intake and constipation but also a positive family history, obesity, and low levels of parental education with an increased prevalence of childhood constipation [38, 43]. The American Academy of Pediatricians suggests a balanced diet that includes whole grains, fruits, and vegetables as the first-line treatment of constipation; however, when comparing fiber supplementation to placebo, there was no significant difference in defecation frequency or resolution of symptoms [36]. We feel there is very little downside, so we agree with this initial approach, along with ensuring adequate fluid intake and physical activity [44]. Children with a developmental age of at least 4 years should also be instructed to have dedicated toilet time for 5–10 min after each meal (three times per day) to encourage regular toileting [45].

If you encounter children who have severe constipation marred by fecal impaction and/or overflow incontinence, disimpaction can be accomplished using either oral or rectal therapies [44–48]: high-dose PEG 3350 (1.5/g/kg/day, max dose of 100 g/day) orally for outpatient use and milk of molasses enemas (mixed 1: 10 mL/kg with maximum of 500 mL) followed with maintenance PEG 3350 have been compared with relatively similar results beyond the first day [47]. In general, enemas relieve symptoms faster than the oral treatment, but either approach is feasible. Other authors have shown that PEG with electrolytes is more effective than suppositories, rectal enemas, or even manual evacuation [49]. If you would like to avoid rectal therapy or if oral disimpaction fails, you may need to take the child to the operating room for disimpaction under general sedation.

Maintenance treatment must be initiated immediately and may be necessary for several months. You should discontinue this treatment only after there are regular bowel movements for several weeks without effort and the child is toilet trained [34, 44]. Tailored therapy is best and you can choose from a variety of laxatives. Unlike adults, laxatives cannot be assumed to work in a similar manner in children due to the fact that the etiology for childhood constipation is typically different than that of their adult counterparts [36, 38]. PEG with electrolytes is our preferred agent and has been shown to be more effective in achieving treatment success compared to other laxatives (lactulose and milk of magnesia) [50–52]. There is also evidence suggesting that mineral oil is efficacious, though chronic use should be avoided, as it has been associated with vitamin deficiencies [52]. Other agents such as probiotics may be helpful in the treatment of functional constipation, but there is very little data available, and we withhold recommendation. Behavioral therapy alone or biofeedback should not be the sole treatment of constipation in children; however, there is some evidence that behavioral intervention plus laxative therapy improves continence in this age group [38, 44].

Key Concept: Several surgeries somewhat unique to children are available for symptomatic severe constipation that is nonresponsive to medical management.

Surgical options for constipation depend in large part on the underlying etiology. Procedures include anal dilation, intra-sphincteric injection of botulinum toxin, antegrade continence enema (ACE), excision of colon and/or megarectum and diversion, and reconstructive proctocolectomy [35, 53]. While (as previously stated) transit studies and total colonic manometry don’t play a major role in the initial evaluation of constipation, we do use them prior to performing a definitive surgery. We find its major use is to ensure the distal-most segment of the colon or remaining rectum will have a functional motility pattern that will effectively allow for the passage of stool [42]. We also recommend a period of inpatient or close home observation to document objective evidence in order to help identify misreporting and exaggerating symptoms and thus avoiding unnecessary operations [53].

Anal dilation and myomectomy of the internal anal sphincter have been performed with the thought that children with constipation have hypertrophy of their internal anal sphincter, and anal dilation would decrease sphincter tone and allow for painless defecation [35]. Unfortunately two double-blinded randomized controlled trials have shown that anal dilation does not benefit children with chronic constipation [35], and we do not generally advocate its use. Myomectomy of the internal anal sphincter has been associated with weakening of the sphincter in subsequent years, and again, we are not strong proponents. Botulinum toxin sphincter injection has reported rates of symptom resolution in up to 94 %, without the long-term problems [16]. While this is generally well tolerated, ~20 % may require repeat injection [16].

Antegrade enemas are a therapeutic option for children who have intractable constipation or fecal incontinence and have failed either (a) a maximal medical management or (b) a sphincter procedure [35, 38, 53, 54]. Originally described by Malone in 1990 [54], subsequent modifications include an appendicostomy placed in an open or laparoscopic fashion, the cecum or rectum reconstructed to create a continent conduit, or a percutaneous cecostomy tube or button placed laparoscopically or open (Fig. 27.2) [35, 54]. The concept remains the same: to deliver antegrade enemas to clean out the entire colon to reduce soiling, with reported success rates of 52–92 % [53]. Each procedure has their own complications including stenosis, prolapse, skin infections, granulation tissue formation, leakage, and prostheses dislodgment [16, 19]. Results do not seem to differ in the complications or outcomes between a right and left ACE [55]. Ultimately, most children with idiopathic constipation can progress to a point they use no oral medications, and the stoma can be no longer used or taken down.

Patients with Hirschsprung’s disease should be managed by the appropriate surgical therapy, which is most often a pull-through procedure that can be performed open or laparoscopically (Figs. 27.3, 27.4, and 27.5) and is one or several stages. One rare, but obviously significant, complication you may see is in children with chronic constipation; a small percentage may develop dilation of the rectum and sigmoid (megarectum). Resection of the dilated segments may be performed in the most extreme cases that have failed all other options, including ACE [53, 57]. Unfortunately, this rarely results in a complete or immediate cure, as children can still have fecal incontinence or constipation and may still need further resection [38]. Yet, almost all will be able to reduce their laxative need, and roughly half will be able to eliminate their laxative requirement altogether [56]. Finally, when combined with the physiological manometric data, the need for permanent stomas secondary to failure for these procedures can be reduced [20].

For those patients with severe problems that are nonresponsive and significantly affect their quality of life, a stoma can be performed. In this case, we prefer to use a temporary diverting loop ileostomy in hopes the child will wish to consider alternative treatments [16]. Finally, there are case reports of a restorative proctocolectomy performed in this final group with generally good results; however, we have little experience with this and feel it should not be undertaken lightly [57].

It is important to manage expectations accordingly. You should let all parties known that 1 year after the commencement for the treatment of constipation, the problem can persist in 50 % of children with another 50 % of those children still suffering from constipation 5 years later [34, 58].

Key Concept: Functional fecal retention with overflow incontinence is the most common cause of fecal soiling. Treatment should be aimed at treatment of constipation.

Constipation can lead to a vicious cycle that begins with painful defecation and ends in voluntary withholding and accumulation of stool in the rectum [16]. With chronicity, the rectum may become dilated, and sensation is gradually lost; therefore, when the softer stool arrives from the more proximal colon, it cannot be accommodated and leaks around the bolus of hard stool [46]. Because of the lack of sensation, this passage of soft stool is not sensed until the incontinence has occurred. This functional problem is typically self-limiting but requires aggressive treatment of constipation [59, 60].

Key Concept: This is a subgroup of patients who lack a history or physical exam findings consistent with constipation or functional fecal retention, but who have evacuation of large bowel movements in their underwear at least once a week. Treatment should be aimed at toilet training and positive feedback.

Confounding things, these children often have daily bowel movements in the toilet with near complete evacuation of stool and normal colonic transition studies [59]. Historically this was considered a manifestation of emotional disturbances in school-aged children; however, studies have not shown any serious psychological disorders, and treatment with psychotherapy alone has not been effective [63]. Treatment for these children should involve parental education and encourage defecation 5 min after each meal, a rewards system, and usage of a diary with avoidance of accusatory toilet training and guilt [59]. Laxatives have been shown to worsen outcomes, and functional non-retentive fecal soiling should be treated differently from retentive soiling [64]. Involvement of a mental health professional may be beneficial [59]. Resolution of the symptoms occurs in only 30 % of the children after 2 years and in 70 % of patients after 4 years with the problem persisting into young adulthood in up to 22 % of the population [65].

Key Concept: These patients present with a wide range in abnormalities, depending on the level of malformation and associated defects, with the management and outcomes often contingent on the malformation. However, a trial at medical therapy is still warranted in this group.

These malformations can be subdivided into three categories: [1] low anomalies, when the rectum has descended below the level of the puborectalis—typically without a fistula to the genitourinary tract and either with or without a cutaneous perineal fistula; [2] intermediate anomalies located at or just below the puborectalis muscle—often having a fistulous connection to the distal genitourinary tract; and [3] high anomalies with the rectum ending above the puborectalis (which may or may not be developed)—with a fistula to the urinary tract or vagina with no perineal opening (Fig. 27.6) [59]. Dependent upon the degree of pelvic floor development, there is great variation in the functional outcomes after repair of these malformations [60]. Generally, lower malformations have good functional outcomes, although they still suffer from occasional incontinence, constipation, an inability to control flatus, or sexual dysfunction [59]^. Patients with lower defects mostly have voluntary bowel movements; however, up to 30 % can still experience soiling. Contrast this with patients with high anomalies, where 30 % may experience voluntary bowel movements and up to 90 % experience soiling [59, 66]. Major advances in pediatric surgery in recent decades have allowed for improved anatomic reconstruction primarily due to the posterior sagittal anorectoplasty (PSARP) for higher anorectal anomalies (Figs. 27.7 and 27.8) [59, 67]. These patients have improved outcomes, with up to half of patients experiencing full continence and only ~20 % having frequent soiling [59, 67], although they may still suffer from severe problems with constipation [66].

Remember that three elements are necessary for continence: functional sphincters, normal rectosigmoid motility, and intact sensation [59, 66]. Children with anorectal malformations who have subsequent defecation disorders should undergo both colonic and anorectal manometric testing to tailor their treatment [68]. It’s not surprising that patients who have a functional internal anal sphincter have higher anal resting tone and better outcomes in continence [69]. However, presence of severe sacral defects is one of the most important negative prognostic factors for continence [59]. These patients (i.e., incontinence from anorectal malformations with minor defects) are ideal for biofeedback, as they are more likely to respond. On the downside, this is time consuming, requires full cooperation from patients, and may not be helpful in patients with hypoplastic sphincters [70]. Therefore, medical treatment should first be used to modify the consistency of stool, with antidiarrheals for loose stools and enemas for those patients that have constipation and overflow incontinence [59, 60]. The enemas may be given retrograde or in an antegrade fashion via an ACE, which tends to be more effective than retrograde enemas [59, 60]. Many patients undergo a second surgery for their incontinence; however, long-term outcomes are no better and may be worse than those who only had one reconstruction [71].

In patients where the anal canal is not surrounded by the sphincter complex, a PSARP has been advocated. The long-term outcomes are variable in this cohort, with a small group of patients having complete resolution of their symptoms and most patients still relying on other measures for continence [72]. These patients may also get fecal soiling due to intractable constipation and overflow incontinence. They may also have a resulting megarectum either from distal obstruction or inadequate treatment of constipation. Although invasive, resection of this dilated portion of bowel can lead to improvement of symptoms of constipation and overflow incontinence. This should be considered only in children who have a functional internal anal sphincter, good anal sphincter tone, and no signs of neuropathy [73].

Key Concept: The degree of bowel functional disorders from spinal pathology depends on the level of the defect. Although medical therapy is again a good first–line therapy, many will require a surgical procedure.

The most common causes of neuropathic bowel in children are spina bifida and myelomeningocele. The most common type of spina bifida affects the lumbosacral region causing bowel and bladder dysfunction [59]. Typical anal changes for these patients are poor voluntary sphincter function, poor colonic motility (specifically the left colon), and poor anorectal sensation [60]. However, the involuntary internal sphincter function is usually spared [60]. More than 50 % of patients with myelodysplasia suffer from fecal incontinence [60]. High lesions affect voluntary sphincter function, sensation, and colonic motility, and these patients are prone to fecal retention [60]. In patients with lower lesions, the functional problem is that patients cannot control their bowel emptying and stools evacuate spontaneously without warning; however, patients can rectally stimulate themselves or strain and have some degree of defecation control [60]. Dietary changes and toilet routines should be established; however, enemas are frequently necessary in these patients, and many of these patients can benefit from an ACE procedure [60].