Evaluation of constipation in children using high-resolution anorectal manometry

Abstract

This prospective, cross-sectional study, conducted from July 2018 to March 2019, aimed to determine the causes of constipation using high-resolution anorectal manometry. Among 33 children enrolled in the study, 31 (94%) children presented with complaints of constipation with mean duration of 2.3 ± 2.5 years and 12 (36.4%) children also had associated complaints of faecal incontinence with mean duration of 3.5 ± 2.8 years. Seven children (21.2%) had normal high-resolution anorectal manometry parameters; anal sphincter hypotonia with decreased squeeze in one child, anal sphincter hypertonia with other abnormal parameters were noted in 25 and absent recto-anal inhibitory reflex in two. The causes of constipation determined were functional constipation in 30 (91%) children, suspected Hirschsprung’s disease in two and suspected dyssynergic defecatory disorder in one. Almost 90% had functional constipation of which anal hypotension and anal hypertension may be a part of chronic functional constipation.

Keywords

Anal hypotonia anal hypertonia dyssynergia functional constipation recto-anal inhibitory reflex high-resolution anorectal manometry

Introduction

Constipation in children accounts for an estimated 3–10% of visits to a paediatrician, with worldwide prevalence varying from 0.7 to 29.6%.^1,2 Constipation may be defined as a decrease in frequency of bowel movements or difficult or painful passage of hard stool.³ The aetiology of constipation can be either organic (in 5%) or functional. Organic causes are Hirschsprung’s disease (HD), anorectal malformations, neuromuscular disease and metabolic cause.^4,5 An anorectal function study, especially high-resolution anorectal manometry (HRAM), helps to differentiate between the two.⁶

Functional faecal incontinence (FI) may be overflow incontinence or functional non-retentive faecal incontinence (FNRFI).¹ Rectal hyposensitivity caused by spinal cord transection, peripheral nerve injury or behavioural factors such as decreased mobility, drugs and psychosocial factors may lead to stool impaction.⁷ Prolonged inhibition of the internal anal sphincter (IAS) and decreased IAS pressure from either faecal impaction or sphincter injury (from surgical division or trauma) is a risk factor for passive FI.

In older children with intractable constipation for more than a year, screening for HD is useful with manometry, which has a sensitivity of 91% and specificity of 94%. An abnormal recto-anal inhibitory reflex (RAIR) is an indication for rectal suction biopsy.^4,5,8 Children with constipation-associated FI have a higher threshold for rectal sensation compared to FNRFI.

Materials and methodology

Ours was a prospective, cross-sectional study conducted between July 2018 and March 2019 at the Department of Pediatric Gastroenterology, Hepatology & Nutrition, Bai Jerbai Wadia Hospital for Children, Mumbai which is a tertiary care hospital. Institutional ethical committee clearance was given. All children up to the age of 18 years with complaints of constipation or FI (infrequent stooling pattern and change in consistency according to the Bristol stool chart) for two or more weeks,⁹ or in children fulfilling Rome III/IV criteria for functional defecation disorders, were included in the study.^5,10 Children with anal fissures on examination, or those whose parents refused to give consent, were excluded. Relevant history, clinical features, general and systemic examination findings, anthropometry and investigations were recorded in a pre-designed format following informed consent from the parents or guardians of the enrolled children.

All patients were subjected to HRAM. The study parameters analysed in cooperative children were anal canal length, resting anal pressure, anal squeeze pressure, anal endurance squeeze pressure, push manoeuvre, rectal sensations, RAIR and cough reflex, whereas only anal canal length, resting anal pressure and RAIR were analysed in uncooperative children after appropriate sedation. The causes of constipation were categorised as functional, suspected HD, suspected dyssynergia, anal sphincter hypotonia and anal hypertonia (Table 1).

Table 1.

The outcomes categorised in the study.

Diagnosis	Resting pressure	Recto-anal inhibitory reflex (RAIR)	Push force	Push anal sphincter pressure
Functional constipation	Normal	Normal	Normal	Normal
Suspected Hirschsprung’s disease	Normal	Absent	–	–
Suspected dyssynergia type 1	Normal	Present	Good	Paradoxical increase
Suspected dyssynergia type 2	Normal	Present	Inadequate	Paradoxical increase
Suspected dyssynergia type 3	Normal	Present	Good	Absent or <20% relaxation
Suspected dyssynergia type 4	Normal	Present	Inadequate	Absent or incomplete relaxation
Anal hypotonia	Decrease	Present	Good	Normal
Anal hypertonia	Increase	Present	Good	Normal

The diagnostic criteria for dyssynergic defecation must include all of the following:

Rome III criteria for functional constipation

During repeated attempts to defecation, a dyssynergic pattern of defecation by anorectal manometry and electromyography demonstrated

One abnormal results in the following tests:

Abnormal balloon expulsion test (>1 min).

Prolonged colonic transit time (Sitzmarks/scintigraphy).

Abnormal defecography (>50% barium retention.

Parameters determined on manometry were as follows:

1. Resting anal pressure: Following correct placement of the probe in the anal canal is confirmed, resting pressure of the anal sphincter was recorded with a stable baseline. The resting pressure of the anal canal is comprised of both internal and external anal sphincter contractions, which is measured over a period of 60 s with no squeeze, after three minutes of familiarisation. This analyses the average resting pressure in the high-pressure zone.

2. Length of the anal canal: Multiple closely spaced recording sites measure anal canal length as proximal and distal extents of the high-pressure zone.

3. Squeeze pressure: A co-operative child is asked to squeeze for five seconds; with a gap of 30 s, the test is repeated three times. The contraction of External anal sphincter (EAS) and puborectalis muscle is analysed. The squeeze pressure is measured as the maximum pressure obtained above the anal resting pressure.

4. Push/strain pressure: The co-operative child is asked to push, as if trying to defecate, for 15 s. This can be repeated for three times with time interval of 30 s. This test analyses the normal EAS relaxation (rectal-sphincter responses) during the manoeuvre. This assists in evaluation of dyssynergia.

5. The RAIR: A balloon placed in the rectum is inflated to elicit the RAIR. The reflex IAS relaxation in response to rectal distension is evaluated by rapidly inflating the rectal balloon with 5 ml increments. Air is rapidly injected to inflate the balloon and then immediately withdrawn within 3–5 sec of inflation. Repeated inflations of the balloon with an increase in volume by 5 ml each time are performed until the RAIR is obtained. The minimum amount of air required to elicit an IAS is determined. The maximum inflation volume for obtaining RAIR is limited to 15 ml for a newborn, 30 ml for infants and 60 ml for older children to elicit > 20% of baseline relaxation.

6. Rectal sensation: The smallest volume of the balloon distension felt by the patient defines the sensation threshold. Insufflation of the balloon is done either with intermittent rectal distension of 5 ml. After each inflation, the distension is maintained for 30 s and balloon is completely deflated. At each increment of air volume injected in the rectal balloon, patient is asked for sensation of fullness, bloating or gas (first sensation), desire or urge to defecate (defined as the lowest volume to elicit an urge to defecate). The maximum tolerated volume associated with a sensation of pain, or when an intense urge arises, is noted.^6,11

HRAM was performed using a, water perfused catheter consisting of a 20 channel HRAM catheter. Pressure data were displayed in topographic form, colour plotted using MMS analysis software, integrated and analysed, comparing with normal values for children (Table 2).^12,13 Glycerine saline enema was used as bowel preparation prior to the test. Patient was put in left lateral position with a sheet covering any exposed area. The perianal region was inspected, digital rectal examination was performed if Rome III/IV criteria were not fulfilled or if the patient had alarm signs and such findings were documented. The different manoeuvres (brief trial of squeeze and push) required during the procedure were explained to co-operative children. Those crying excessively or generally uncooperative were sedated prior to the procedure. The lubricated water perfused HRM catheter was inserted gently through the anus into the rectum. If resistance was felt, then catheter was pulled back before re-advancing. Once the placement was confirmed from the anal verge, the catheter was taped into position to prevent inadvertent movement during the procedure. After insertion, the child was allowed to relax with it in situ for three minutes. Then a standard non-latex balloon mounted onto the catheter tip was inflated with different volume levels to elicit RAIR.¹¹ The International Anorectal Physiology Working Group protocol was followed.¹⁴

Table 2.

Normal values of HRAM variables compared in the study.^13,14

HRAM parameters	Normal values in children
Mean resting anal canal pressure (mmHg)¹³	Neonates – 31.07 ± 10.9^a Infants – 42.43 ± 8.9^b Children -43.43 ± 8.79^c
Mean squeeze pressure (mmHg)¹⁴	191 ± 64
Mean anal canal length (cm)¹³	Neonates – 1.67 ± 0.34 Infants – 1.86 ± 0.6 Children – 3.03 ± 0.52
Mean volume to elicit RAIR (ml)¹³	Neonates – 9.67 ± 3.6 Infants – 14 ± 9.5 Children – 25 ± 11.6
Threshold for first rectal sensation (ml)¹⁴	24.4 ± 23.98 cm³
Threshold for first urge (ml)¹⁴	45.9 ± 34.55 cm³
Threshold for intense urge (ml)¹⁴	91.6 ± 50.17 cm³

HRAM: high-resolution anorectal manometry; RAIR: recto-anal inhibitory reflex.

^aNeonates upto one month of age.

^bInfants – one month to one year.

^cChildren more than one year.

Source: reproduced from Banasiuk et al., 2016¹³ and Carrington et al., 2020.¹⁴

Results on continuous variables were presented as Mean ± SD and results on categorical variables were presented in numbers (%).

Results

Out of 40 patients counselled for the test, HRAM was conducted in 33 patients whose parents or guardians gave consent. Their mean age at presentation was 5.7 ± 4.3 years (the youngest and oldest patients enrolled being 2 months and 16 years respectively). Median age of presentation was 4.3 years. IQR: 6.5 years. (Q1: 2.5 years; Q3: 9 years).

Of the 33 children, 24 (73%) were boys. Mean duration of constipation was 2.3 ± 2.5 years in 31 (94%). Twelve (36%) children also had associated FI with mean duration of 3.5 ± 2.8 years. One other child of two months had altered frequency and consistency of stools with abdominal distension and another nine years old had excessive straining on defecation following an anoplasty performed at nine months of age.

Eight children were toilet-trained confirmed by their parents out of 22 in whom this could be elicited. Four had a history of delayed passage of meconium at birth. Six had faulty posture of standing while defecating and five had a stool withholding posture. Eight had a history of uncooperative behaviour with regard to toilet use, either children refuse or need a constant reminder to use the toilet. Six had a history of blood in the stools. Ten had abdominal pain. Eight had painful defecation. Three had history of abdominal distension. Eleven were taking laxative treatment for a mean duration of 1.6 ± 1.0 years and 17 had received an enema at least once before the study. Sedation was used on 13 (39.4%) children either by triclofos or midazolam.

On analysing the HRAM variables, seven patients (21%) had normal HRAM parameters, one had anal sphincter hypotonia with decreased squeeze and anal sphincter hypertonia with other abnormal parameters were noted in 25 (83%).

The subtypes of anal hypertension and their HRAM parameters are depicted in. The causes of constipation determined were functional constipation in 30 (91%) patients, suspected HD in 2 and suspected dyssynergic defecatory disorder in one child.

Table 3.

High-resolution anorectal manometry (HRAM) parameters in anal hypertension group.

Diagnosis (n)	Functional anal canal length (cm)	Mean anal resting pressure (mmHg)	Mean anal squeeze pressure (mmHg)	Mean RAIR volume (ml)	Mean first sensation volume (ml)	Mean first urge volume (ml)	Mean intense urge volume (ml)
Anal hypertension (15)	1.8 ± 0.5	97 ± 33.4	144.6 ± 36	11 ± 6.6	34 ± 13.4	56.3 ± 14.5	66.3 ± 15.
Anal hypertension with decreased rectal sensation (4)	1.9 ± 0.24	90.3 ± 17.3	160.3 ± 7.2	10 ± 5.8	80 ± 33.7	123.5 ± 58.5	185 ± 73.6
Anal hypertension with decreased squeeze (3)	2.3 ± 0.2	69.2 ± 8.6	81.7 ± 13.2	8.3 ± 5.7	35 ± 7	50	60
Anal hypertension with absent RAIR (1)	0.4	86		20 (RAIR relaxation of 4%)
Anal hypertension with absent RAIR and decreased rectal sensation (1)	2.1	74	133	85	80	110	140
Anal hypertension with decreased rectal sensation and dyssynergia (1)	1.7	78	147	5	70	80	100

RAIR: recto-anal inhibitory reflex.

Discussion

Indian data on childhood constipation are limited. HRAM is used in evaluation of sphincter function in FI, pelvic floor dyssynergia, HD and to evaluate postoperative symptomatology to decide if patient is a candidate for biofeedback therapy.¹¹ However, owing to there being no standard paediatric HRAM protocol, as well as difficulty in understanding various manoeuvres as performed in adults, performing this procedure in children is challenging. Sedation either by triclofos or midazolam is not thought to affect the anal sphincter function during the procedure.^11,15

The most common cause of FI in children is due to faecal impaction causing decrease in resting pressure, decrease in maximum squeeze pressure, decrease in maximum tolerable rectal volume, decrease in volume to elicit RAIR and impaired external anal sphincter response to rectal distension.^11,16 Our study highlights the need for children who refuse or need a constant reminder to use the toilet, and those with stool withholding behaviour to be counselled. Social factors such as reluctance to use public or unhygienic toilets, behavioural factors like being engrossed in play, gadgets or television need to be addressed. Appropriate advice on toilet training, regular bowel habits, dietary advice and adequate hydration need to be given.

Children using laxatives or having enemas should alert a need for an appropriate diagnosis, counselling and treatment. HRAM is very useful in this respect, but must be done with close attention to detail. It is mandatory if a short course of treatment fails to resolve the problem.

To correlate our findings, a larger sample size is required. There is a need to generate more data on paediatric normal values and values pertaining to organic causes. There are discrepancies in the values generated by different types of catheters – water perfused, solid state and the system used. Furthermore, there may be significant variation of values in different populations. There is also a need for specialists (who may be nurse practitioners) to be trained to do and interpret this test.

HRAM should become a routine screening investigation to supplement other modalities such as magnetic resonance or fluoroscopic defecography, endoscopic anal ultrasound and gut transit studies in children with defecation disorders.^17,18

Conclusion

HRAM aids in diagnosis of various causes of constipation. Almost 91% patients had functional constipation of which anal hypotension and anal hypertension may be associated with chronic functional constipation. By differentiating the cause of constipation, more appropriate treatment modalities can be offered.

Footnotes

Authors’ contribution

VSP, SM, NSS and IS managed the patients. IS designed the study. VSP, SM and NSS did data collection and statistics. VSP, SM, NSS and IS wrote the manuscript. IS did critical review of the manuscript and will act as guarantor of the paper.

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iDs

Vishrutha S Poojari

Naman S Shetty

References

Kuizenga WA and Benninga MA. Functional constipation and incontinence. In: Wyllie R, Hyams J and Kay M (ed) Pediatric gastrointestinal and liver disease. 5th ed. Alpharetta, GA: Elsevier, 2016, pp.124–136.

Mugie

Benninga

Di Lorenzo

. Epidemiology of constipation in children and adults: a systematic review. Best Pract Res Clin Gastroenterol 2011; 25: 3–18.

Gupte S and Anderson RA. Constipation. In: Gupte S (ed) The short textbook of pediatrics. 11th ed. New Delhi, India: Jaypee, 2009, pp.472–473.

Tabbers

DiLorenzo

Berger

, et al. Evaluation and treatment of functional constipation in infants and children: evidence-based recommendations from ESPGHAN and NASPGHAN. J Pediatr Gastroenterol Nutr 2014; 58: 258–274.

Levy

Lemmens

Vandenplas

, et al. Functional constipation in children: challenges and solutions. Pediatric Health Med Ther 2017; 8: 19–27.

Rodriguez

Sood

Di Lorenzo

, et al. An ANMS-NASPGHAN consensus document on anorectal and colonic manometry in children. Neurogastroenterol Motil 2017; 29: e12944–e12944.

Rao SSC and Rattanakovit K. Anorectal disorders- Fecal Impaction, Descending Perineum Syndrome, Rectocele, and Levator Ani Syndrome. In: Rao SSC, Parkman HP and McCallum RW (eds) Handbook of gastrointestinal motility and functional disorders. West Deptford, NJ: SLACK Incorporated, 2015, pp. 279–289.

De Lorijn

Kremer

LCM

Reitsma

, et al. Diagnostic tests in Hirschsprung disease: a systematic review. J Pediatr Gastroenterol Nutr 2006; 42: 496–505.

Baker

Liptak

Colletti

, et al. Constipation in infants and children: evaluation and treatment. A medical position statement of the North American Society for Pediatric Gastroenterology and Nutrition [published correction appears in J Pediatr Gastroenterol Nutr 2000; 30: 109]. J Pediatr Gastroenterol Nutr 1999; 29: 612–626.

10.

Hyams

Di Lorenzo

Saps

, et al. Childhood functional gastrointestinal disorders: Child/adolescent. Gastroenterology 2016; 150: 1456–1468.

11.

Hong

. Clinical applications of gastrointestinal manometry in children. Pediatr Gastroenterol Hepatol Nutr 2014; 17: 23–30.

12.

Kumar

Ramadan

Gupta

, et al. Manometric tests of anorectal function in 90 healthy children: a clinical study from Kuwait. J Pediatr Surg 2009; 44: 1786–1790.

13.

Banasiuk

Banaszkiewicz

Dziekiewicz

, et al. Values from three-dimensional high-resolution anorectal manometry analysis of children without lower gastrointestinal symptoms. Clin Gastroenterol Hepatol 2016; 14: 993–1000.

14.

Carrington

Heinrich

Knowles

, et al. The International Anorectal Physiology Working Group (IAPWG) recommendations: standardized testing protocol and the London classification for disorders of anorectal function. Neurogastroenterol Motil 2020; 32: e13679–e13679.

15.

Di Lorenzo

Hillemeier

Hyman

, et al. Manometry studies in children: minimum standards for procedures. Neurogastroenterol Motil 2002; 14: 411–420.

16.

Stendal

. Practical guide to gastrointestinal function testing, Malden, MA: Blackwell Science, 1997, pp. 247–266.

17.

Tang

Leung

Hung

, et al. Application of three dimensional high resolution anorectal manometry to demonstrate anal sphincter pressure asymmetry in children after anorectal surgery: a pilot study. HK J Paediatr (new series) 2017; 22: 204–208.

18.

Scott

Carrington

. The London classification: improving characterization and classification of anorectal function with anorectal manometry. Curr Gastroenterol Rep 2020; 22: 1–2.