Functional Constipation in Children


Age

<4 years

Developmental age of ≥4 years

Rome III criteria

• <3 defecations per week

• <3 defecations in the toilet per week

• ≥1 episode of fecal incontinence per week after the acquisition of toileting skills

• ≥1 episode of fecal incontinence per week

• History of excessive stool retention

• History of retentive posturing or excessive volitional stool retention

• History of painful or hard bowel movements

• History of painful or hard bowel movements

• Presence of a large fecal mass in the rectum

• Presence of a large fecal mass in the rectum

• History of large diameter stools which may obstruct the toilet

• History of large diameter stools which may obstruct the toilet
 
Must fulfill ≥2 criteria for ≥1 month prior to diagnosis

Must fulfill ≥2 criteria at least once per week for ≥2 months prior to diagnosis

Insufficient criteria for diagnosis of IBS

Rome IV criteria

Must include 1 month of at least 2 of the following in infants up to 4 years of age:

Must include 2 or more of the following occurring at least once per week for a minimum of 1 month with insufficient criteria for a diagnosis of irritable bowel syndrome:

1. 2 or fewer defecations per week

1. 2 or fewer defecations in the toilet per week in a child of a developmental age of at least 4 years

2. History of excessive stool retention

2. At least 1 episode of fecal incontinence per week

3. History of painful or hard bowel movements

3. History of retentive posturing or excessive volitional stool retention

4. History of large-diameter stools

4. History of painful or hard bowel movements

5. Presence of a large fecal mass in the rectum

5. Presence of a large fecal mass in the rectum

In toilet-trained children, the following additional criteria may be used:

6. History of large diameter stools that can obstruct the toilet

6. At least 1 episode/week of incontinence after the acquisition of toileting skills

After appropriate evaluation, the symptoms cannot be fully explained by another medical condition

7. History of large-diameter stools that may obstruct the toilet





Physiology



Meconium Passage and Defecation Frequency


In more than 99 % of healthy term neonates, the first meconium passes within the first 48 h of life [5, 6]. Delayed passage of the first meconium beyond the first 48 h of life is suggestive for an organic defecation disorder (e.g., Hirschsprung’s disease). During the first months of life, the defecation frequency may vary from child to child, this is partially dependent on feeding type; breastfed children have a higher defecation frequency than formula-fed infants [6]. In the first weeks of life, the defecation frequency lies around 4 stools a day, this frequency gradually decreases over time until it is approximately once a day in children at the age of 4 years [6, 7]. In older children, defecation usually occurs either daily or every other day [8].


Defecation Dynamics


The physiological dynamics of defecation are complex and rely on several intricate processes involving the autonomic and somatic nervous system, the pelvic floor muscles, and the internal and external anal sphincters. In the colon, feces is propelled by propagating colonic contractions. Several different colonic motor patterns have been described [9, 10], but the most well-recognized propagating motor patterns are high-amplitude propagating contractions (HAPCs ). These motor patterns are associated with the mass movement of colonic content and spontaneous defecation in healthy adults [11, 12]. Anterograde propagation of feces through the colon leads to filling of the rectum, which induces a relaxation of the internal anal sphincter, allowing feces to travel further down the anal canal; this reflex is known as the recto-anal inhibitory reflex (RAIR ). Subsequently, sensory stimuli caused by rectal distension and by the contact between fecal material and the mucosa of the proximal part of the anal canal result in an urge to defecate. At this point, voluntary contraction of the external anal sphincter can postpone defecation, by moving the fecal load back, higher up in the anal canal and rectum, until the place and time are appropriate for defection. When defecation is initiated, voluntary relaxation of the external anal sphincter and the pelvic floor musculature (i.e., the puborectalis muscle and levator ani) allows for an easy defecation process. In young children, this can be promoted by proper support of the feet when sitting on the toilet and a relaxed posture. Then, by gently increasing the intra-abdominal pressure, stools can be expelled from the rectum.


Pathophysiology


The pathophysiology of FC is incompletely understood; multiple factors are likely to play a role in its pathogenesis and may affect different phases of the physiological defecation dynamics.


Age of Manifestation


FC occurs in children of all ages, but there are three phases in life when children seem to be more prone to develop constipation: (1) in infancy, concomitant with changes in feeding (e.g., change from breastfeeding to formula-feeding, introduction of solid foods); (2) around the time of toilet training; and (3) in school children who avoid going to the toilet at other places than home [13]. This suggests that both dietary and behavioral factors play an important role in the pathogenesis of FC.


Stool Withholding Behavior


One important recognized etiologic factor, especially in young children, is stool withholding behavior. This often occurs after a negative experience such as a hard, painful, or frightening bowel movement [14]. Stool withholding behavior can lead to the accumulation of a large fecal mass in the rectum that is difficult to evacuate, also known as fecal impaction. Fecal impaction may lead to overflow fecal incontinence which is the involuntary loss of soft stools that pass the solid, obstructing, fecal mass. Stool withholding can lead to a negative chain of events; due to a painful defecation experience, the child voluntarily retains the stools in an attempt to prevent another painful bowel movement, causing the stools to become harder and more difficult to evacuate, leading to more pain during defecation. Withholding behavior may eventually lead to dyssynergia, this occurs when the coordination of the muscles involved in defecation are inadequately coordinated during defecation. Instead of relaxing the muscles involved in normal defecation, muscles are tightened in a poorly coordinated attempt at defecation, preventing stools to be expelled from the rectum and sustaining constipation.


Colonic Dysmotility


Propagation of feces through the colon is an essential step in the physiology of defecation. In children with long-standing symptoms of FC the passage of feces through the colon is often delayed [15]. It is not entirely clear whether this delay in colonic transit time plays a causative role or if it is an effect of long-standing constipation and becomes a perpetuating factor, resulting in a detrimental causal sequence.

Studies utilizing colonic manometry have revealed that in children with intractable FC, several types of colonic dysmotility can be differentiated. In healthy humans, stretching of the stomach after a meal induces an increase in motility of the colon, this response is known as the gastrocolic reflex. Colonic manometry studies have shown that this reflex is impaired in a subset of children with FC, which may indicate an impaired extrinsic innervation [16, 17]. Furthermore, it has been shown that a proportion of children with FC have incompletely propagating HAPCs or a general lack of HAPCs in response to a stimulant laxative, which likely implies an intrinsic (neurogenic or myogenic) pathophysiological process. Once again, it remains uncertain whether these findings are cause, effect, or a combination of both.


Psychosocial Factors


Although the precise underlying pathophysiological mechanisms are not always clear, psychosocial factors such as major life events, socioeconomic status, educational level, and parental child-rearing attitudes might play a role in the pathophysiology of FC [3, 18, 19]. Furthermore, behavioral disorders such as autism spectrum disorders and attention deficit hyperactivity disorder are associated with a higher risk of childhood constipation [20, 21].


Genetics


Since FC seems to occur more often in certain families, genetic factors may contribute to the etiology of childhood constipation [22]. However, studies have failed to identify mutations in specific genes associated with FC [23].


Microbiota


Gut microbiota differences have been identified between children with and without FC, suggesting that gut microbiota may play a role in the pathogenesis of FC [24]. One of the possible mechanisms in which the gut microbiota may potentially influence gut motility is by the production of methane as a consequence of anaerobic fermentation of carbohydrates and the production of hydrogen in the gut [25]. There is strong evidence from animal studies that methane delays intestinal transit, possibly acting as a neuromuscular transmitter, and methane production has been associated with constipation in adults [2527].


Bile Salts


There has been an increasing interest in bile salt metabolism as a potential pathophysiological factor in FC; deconjugated bile salts have the potential to function as endogenous laxatives by increasing colonic motility and fluid secretion [28, 29]. In a subset of children with FC, bile acid metabolism has been shown to be altered, leading to a decreased secretory activity. This suggests that bile acid metabolism may play a role in the pathophysiology of constipation in a subset of children [30].


Evaluation


The evaluation of a child with constipation should always aim to differentiate between FC and constipation due to an organic cause. The diagnosis of FC is based on a thorough medical history and a complete physical examination, additional investigations are usually not required [2].


Medical History


In the medical history , questions should address defecation frequency, stool consistency, painful bowel movements, size of the stools, episodes of fecal incontinence, and a history of withholding behavior (Table 42.1). Keeping a daily bowel diary can be useful to gather reliable information about a child’s bowel habits. The Bristol Stool Scale or the Modified Bristol Stool Form Scale for Children can be helpful in the assessment of stool consistency [31]. Special attention should be paid to questions about withholding behavior, as this behavior may not be recognized as such by parents and may even be wrongfully interpreted as straining to defecate. Questions regarding stool withholding behavior should therefore be clear and illustrated with examples. In infants, withholding may be characterized by grunting, arching of the back, and tightening of the legs. In toddlers, squeezing the buttocks together, crossing the legs, standing on the toes, and rocking back and forth are distinctive signs of withholding. The medication history should include the use and efficacy of oral laxatives, enemas, and other medications that potentially influence gastrointestinal motility.


Alarm Symptoms


To differentiate between FC and constipation with an organic cause, alarm symptoms suggestive for an organic cause should be sought out (Table 42.2) [2]. Alarm symptoms indicative of an organic cause include delayed passage of meconium, a history of bloody stools without the presence of a fissure, failure to thrive, and severe abdominal distensio n. Furthermore, if parents report smearing of feces, this should raise the suspicion of sexual abuse.


Table 42.2
Alarm signs and symptoms in constipation











































Constipation starting extremely early in life (<1 month)

Passage of meconium >48 h

Family history of Hirschsprung’s disease

Ribbon stools

Blood in the stools in the absence of anal fissures

Failure to thrive

Fever

Bilious vomiting

Abnormal thyroid gland

Severe abdominal distension

Perianal fistula

Abnormal position of anus

Absent anal or cremasteric reflex

Decreased lower extremity strength/tone/reflex

Tuft of hair on spine

Sacral dimple

Gluteal cleft deviation

Extreme fear during anal inspection

Anal scars


From Tabbers MM, DiLorenzo C, Berger MY, Faure C, Langendam MW, Nurko S, et al. Evaluation and treatment of functional constipation in infants and children: evidence-based recommendations from ESPGHAN and NASPGHAN. J Pediatr Gastroenterol Nutr. 2014 Feb;58(2):258–74, with permission


Differential Diagnostic Considerations


Besides organic causes of constipation and devastating causes of FC such as sexual or physical abuse, the differential diagnosis should also include harmless conditions that may be misinterpreted as FC; infrequent defecation in breastfed infants and screaming or crying before or during defecation in infants can be worrying to parents but are often innocuous. Infant dyschezia is a functional gastrointestinal disorder in young children that is defined as straining and crying for at least 10 min before successful passage of soft stools in an infant younger than 9 months of age without any other health problem [32]. Parents report that their child turns red or purple during defecation, but is usually passing soft stools several times daily. This is a self-limiting condition, which does not require any medication or intervention. It is thought to be caused by a lack of coordination between increased intra-abdominal pressure preceding defecation and relaxation of the pelvic floor [33]. Furthermore, approximately 10 % of breastfed infants defecate once every 7–10 days, without any other symptom of FC and while still gaining weight normally. This is usually an innocent and self-limiting phenomenon related to breastfeeding and does not require any treatment [34].


Physical Examination


Assessment of weight and height is of key importance since detection of failure to thrive may be a sign of an organic cause of constipation. A physical examination may be helpful in diagnosing constipation and is especially important in detecting alarm signs. It primarily consists of examination of the abdomen, the perianal region, and the lumbosacral region.

Abdominal examination mainly focuses on the detection of a palpable fecal mass or scybala. Perianal inspection should be performed in all children; the physician should look for anatomic abnormalities, perianal feces, fissures, scars, and erythema. The presence of fissures can be a sign of hard or large stools, but can also be a sign of sexual abuse. Hematomas in the perianal region are highly suspicious of abuse. Special attention should be paid to abnormal behavior during physical examination (e.g., sexual acting out, extreme fear) [35]. Although digital rectal examination provides valuable information on the presence of a rectal fecal mass, anorectal sensation, and sphincter tone, it is not necessary for the diagnosis of FC if a child already fulfils 2 or more Rome III criteria (Table 42.1) [2]. If a child fulfils one of the Rome III criteria, a digital rectal examination is recommended since it may help establish the diagnosis of FC. Examination of the lumbosacral region may reveal the presence of a dimple, a tuft of hair, or gluteal cleft deviation, indicative of an organic cause of constipation (e.g., spina bifida).


Laboratory Testing


Laboratory testing (e.g., for hypothyroidism, celiac disease, or hypercalcemia) in children with constipation is only indicated when there is a suspicion for an underlying organic disease, it does not belong in the routine workup of children with FC.


Radiology



Abdominal Radiography


A plain abdominal X-ray is not the appropriate tool to diagnose constipation. The sensitivity and specificity rates are unsatisfactory, and low inter- and intra-observer reliability has been reported for the different scoring systems (Barr, Leech, Blethyn) that are used to evaluate fecal load based on abdominal X-rays [2, 36, 37].


Colonic Transit Time


Although determining colonic transit time can be helpful in the evaluation of colonic motility, there is no evidence to support the routine measurement of colonic transit time in the diagnostic workup of FC [2]. Colonic transit time can be determined with a radiopaque marker test; radiopaque markers are ingested orally and the amount of intra-abdominal markers is then determined using an abdominal X-ray [3840]. A colonic transit time <62 h is usually considered to be normal [40, 41] (see Chap. 15). An extremely prolonged colonic transit time of more than 100 h indicates a severe form of constipation [40]. Another method to determine colonic transit time is radionuclide scintigraphy; after ingestion of radioactive isotopes, colonic transit is measured with a large-field-view gamma camera. Scintigraphy is a more novel technique than the radiopaque marker test, but its use is less widespread [4244] (see Chap. 15).

In children with fecal incontinence in whom the diagnosis is not clear, a colonic transit study can be useful to discriminate between FC and functional nonretentive fecal incontinence, a disorder characterized by fecal incontinence without signs of constipation (see Chap. 43) [2, 45].


Contrast Enema


A contrast enema is a useful tool to identify anatomic abnormalities of the anorectum; after infusion of contrast fluid into the rectum an abdominal X-ray is obtained, visualizing the distribution of contrast fluid in the distal gastrointestinal tract. Contrast enemas do not belong in the routine workup of children with FC, but may be useful to detect mechanical causes of constipation (e.g., anatomical abnormalities or complications after colorectal surgery) [46].


Ultrasonography


Transabdominal ultrasonography has been used to measure the transverse rectal diameter [47, 48]. An increased rectal diameter (>30 mm) is often considered to be suggestive for fecal impaction [49, 50]. Although transabdominal ultrasonography is a promising technique for assessment of rectal diameter, there is currently insufficient evidence that the transverse diameter can be used as a reliable predictor of constipation and fecal impaction in children [2, 51].


Manometry


Manometry allows for measurement and quantification of intraluminal pressure and contact force in the gastrointestinal tract; this technique can be utilized to gain insights into gastrointestinal motility.


Anorectal Manometry


Anorectal manometry is a helpful tool in the assessment of anorectal neuromuscular integrity. It can be used to assess the rectoanal inhibitory reflex, anal sphincter pressure, rectal sensation, and defecation dynamics; therefore it is a useful instrument to rule out Hirschsprung’s disease and to detect anal sphincter achalasia or dyssynergia [42] (see Chap. 10). The presence of a normal rectoanal inhibitory reflex is considered to be sufficient to reliably rule out Hirschsprung’s disease. However, an absent rectoanal inhibitory reflex is not sufficient to diagnose Hirschsprung’s disease; this requires confirmation with histochemical evaluation of a rectal biopsy (see Chap. 25). The performance and analysis of anorectal manometry belongs in specialized centers and should not be routinely applied in children suspected of FC.


Colonic Manometry


Colonic manometry assesses colonic motility and can be used to identify colonic neuromuscular disorders (Fig. 42.1a, b). It is often used to guide decision-making in the surgical treatment of FC. This investigation usually includes the following recording periods within one measurement: (1) fasted state; (2) after ingestion of a meal; and (3) after intraluminal administration of a stimulant laxative [16]. Until now, most of the attention has been focused on high-amplitude propagating contractions (HAPCs) [5255]. The presence of these motor patterns is considered to be an important marker for colonic neuromuscular integrity [56]. With the development of high-resolution colonic manometry catheters, more motor patterns have been identified and their importance in FC is under current investigation [10, 17, 57] (see Chap. 9).

A191925_2_En_42_Fig1_HTML.gif


Fig. 42.1
Color plot of a water-perfused high-resolution colonic manometry performed in a 10-year-old girl with functional constipation. The most proximal of the 36 channels is depicted at the top of both figures, the most distal channel at the bottom. Time is represented at the X-axis. The color legend on the left represents the amplitude of the contractions. (a) After a high-caloric, high-fat meal, several post-prandial HAPCs were observed. (b) After administration of bisacodyl through the central lumen of the manometry catheter numerous HAPCs were observed, these contractions resulted in stools and flatulence


Management


The management of FC in children consists of non-pharmacological and pharmacological treatment modalities. Figure 42.2 represents a treatment pyramid for the management of children with FC.

A191925_2_En_42_Fig2_HTML.gif


Fig. 42.2
Treatment pyramid for FC. FC is usually treated in a step-up approach, starting with non-pharmacological interventions and osmotic laxatives (PEG) (bottom of the pyramid). If these measures are unsuccessful, use of more invasive treatment modalities may be necessary (top of the pyramid). Abbreviations: PEG polyethylene glycol, ACE antegrade continence enemas, SNS sacral nerve stimulation, TES transcutaneous electrical stimulation


Education


Education is the first step in the non-pharmacological treatment of FC [58]. This should include an explanation of physiological defecation dynamics, tailored to the developmental age of the child. The negative chain of events that may have been prompted by a painful defecation experience should be explained to parents and, if possible, children. It is important to describe the pathophysiology of overflow incontinence and the pivotal role that withholding behavior plays in this process.


Toilet Program and Reward System


Because stasis of feces in the rectum can maintain constipation, it is important to evacuate the rectum regularly. In children with a developmental age of ≥4 years, this can be established by introducing a toilet training program, with scheduled toilet sits throughout the day, usually after every meal and after coming home from school. The toilet sits are scheduled after a meal to benefit from the gastrocolic reflex which increases colonic peristalsis upon distension of the stomach. To motivate children to maintain this toilet training program, a reward system can be introduced. By rewarding the child with small gifts for completing toilet trainings, the child is positively reinforced to comply with therapy. A nonaccusatory approach of both physicians and parents is of key importance since children may feel guilty or embarrassed, especially about episodes of fecal incontinence [58]. Only rewarding periods without fecal incontinence is therefore not recommended, this may increase feelings of guilt and can be experienced as punishment for having fecal incontinence.


Dietary Fiber, Fluid, and Physical Activity



Fiber


Although insufficient fiber intake is associated with FC [59], there is insufficient evidence to support the use of supplementary fiber in excess of the daily recommended intake in children with FC [2, 60].


Fluid


One study assessing extra fluid intake in children with FC showed insufficient evidence for an advantageous effect on constipation symptoms [61]. Therefore, extra fluid intake in children with FC in excess of a normal fluid intake is not recommended [2]. An exception should be made for extra fluid that is recommended for medication intake, such as polyethylene glycol, which needs to be dissolved in water.


Physical Activity


Although physical activity may be associated with a decreased risk of developing FC at the preschool age [62], no studies have been performed to assess the effect of increasing physical activity to treat symptoms of constipation in children [2].


Probiotics


Studies on the use of probiotics have been conducted in children, but to date, there is insufficient evidence to support the use of probiotics in the treatment of childhood constipation [60, 63].


Biofeedback Training


Biofeedback training utilizes reinforcing stimuli in an attempt to achieve a recognizable sensation and encouraging an appropriate learnt response. In theory, this may help children with dyssynergia to adapt their defecation dynamics. However, currently available evidence does not support the use of biofeedback training for the treatment of childhood constipation [64].


Treatment


The pharmacological treatment of FC mainly consists of treatment with laxatives and involves three steps: disimpaction, maintenance treatment, and weaning. The pharmacological treatment options, including recommended dosages, are summarized in Table 42.3 [37].


Table 42.3
Pharmacological management of functional constipation in children



























































Oral laxatives

Dosage

PEG 3350/4000

Maintenance: 0.2–0.8 g/kg/day in 1–2 doses

Fecal disimpaction: 1–1.5 g/kg/day (max 6 days)

Lactulose

7 months–18 years: 1–2 g/kg/day, in 1–2 doses

Lactitol

1–6 years: 0.5–1 g/kg/day in 2–3 doses

6–12 years: 10–30 g/day in 2–3 doses

12–18 years: 20–60 g/day in 2–3 doses

Bisacodyl

3–10 years: 5 mg/day, in 1 dose/day (at night)

>10 years: 5–10 mg/day, in 1 dose/day (at night)

Senna

2–6 years: 2.5–5 mg/day, in 1–2 doses/day

6–12 years: 7.5–10 mg/day, in 1–2 doses/day

>12 years: 15–20 mg/day, in 1–2 doses/day

Sodium picosulfate

1 month-4 years: 2.5–10 mg/day, in 1 dose/day

4–18 years: 2.5–20 mg/day, in 1 dose/day

Magnesium hydroxide

2–5 years: 0.4–1.2 g/day, in 1 or more doses

6–11 years: 1.2–2.4 g/day, in 1 or more doses

12–18 years: 2.4–4.8 g/day, in 1 or more doses

Rectal laxatives/enemas

Dosage

Bisacodyl

2–10 years: 5 mg/day, in 1 dose/day (at night)

>10 years: 5–10 mg/day, in 1 dose/day (at night)

Sodium lauryl sulfoacetate

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Aug 29, 2017 | Posted by in GASTROENTEROLOGY | Comments Off on Functional Constipation in Children
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