Diagnostic tests in Hirschsprung disease: a systematic review

OBJECTIVE

We conducted a systematic review to determine and compare the diagnostic accuracy of contrast enema (CE), anorectal manometry (ARM) and rectal suction biopsy (RSB) in infants suspected of Hirschsprung disease.

DESIGN

This is a systematic review.

DATA SOURCES

Articles were identified through electronic searches in Medline, EMBASE.com and Cochrane Controlled Trials Register. Searches were limited to articles published after 1966 in PubMed and after 1980 in EMBASE.com.

STUDY SELECTION

Studies were included if infants underwent at least one of the following tests: CE, ARM or RSB, followed by full-thickness biopsy and/or clinical follow-up as the reference standard.

DATA EXTRACTION

Two reviewers independently assessed the methods of data collection, patient selection, blinding and prevention of verification bias and description of the test protocol and reference standard. Data to construct 2 x 2 tables were abstracted for each test.

RESULTS

Twenty-four studies met our inclusion criteria, but 2 studies were subsequently excluded for statistical analysis because data was missing to construct the 2 x 2 table. RSB (14 studies for a total of 993 patients) was the most accurate test, having both the highest mean sensitivity (93%; 95% confidence interval [CI], 88%-95%) and mean specificity (98%; 95% CI, 95%-99%). Sensitivity and specificity of ARM (9 studies for a total of 400 patients) were similar to those of RSB (91% vs 93%, P = 0.73 and 94% vs 98%, P = 0.08, respectively). Sensitivity and specificity of CE (12 studies for a total of 425 patients) were significantly lower than those of RSB and ARM, with mean sensitivity and mean specificity of 70% and 83%, respectively.

CONCLUSIONS

RSB and ARM are the most accurate tests in the diagnostic workup of Hirschsprung disease.

Functional constipation in infants: a follow-up study

Our objective of this study was to describe the clinical course of severe functional constipation in early childhood. Eligible patients were 47 children (60% boys; median age, 3.5 months) who had constipation in their first year of life. Follow-up data were obtained through a standardized questionnaire. Success was defined as a period of at least 4 weeks with > or =3 painless bowel movements per week. Six months after initial evaluation, 69% of the children were recovered. After initial success, a relapse occurred in 15% of the children within 3 years. A duration of symptoms <3 months before referral correlated significantly with better outcome. We conclude that most infants with severe constipation evaluated at a tertiary center are recovered after 6 months. Early therapeutic intervention may beneficially contribute to the resolution of constipation.

Interstitial cells of Cajal are involved in the afferent limb of the rectoanal inhibitory reflex

BACKGROUND AND AIMS

Interstitial cells of Cajal (ICC) have been shown to be involved in nitrergic neurotransmission of the lower oesophageal sphincter and pylorus. Here we studied the role of ICC and nitric oxide (NO) in the inhibitory neurotransmission of the murine internal anal sphincter (IAS).

METHODS

The rectoanal inhibitory reflex, rectal compliance, and relaxation of the isolated IAS to electrical stimulation were measured in controls, KIT (W)/KIT (Wv) mice, and neuronal NO synthase (nNOS) deficient mice. In addition, we evaluated the effect of blockade of nNOS using N-nitro-L-arginine methyl ester. Distribution of nNOS positive neurones and ICC in the IAS was assessed immunohistochemically.

RESULTS

KIT positive ICC were present in a dense network in the IAS of controls but not in KIT (W)/KIT(Wv) mice. Relaxation of IAS muscle strips induced by electrical stimulation was diminished in nNOS-/- mice but not in KIT (W)/KIT (Wv) mice. Blockade of NOS reduced the relaxation of IAS muscle strips in both mice. Relaxation of the IAS to rectal distension was significantly diminished in KIT (W)/KIT (Wv) mice and nNOS deficient mice. In concert, in vivo blockade of NOS attenuated the relaxation of the IAS in controls. No significant difference in compliance was found.

CONCLUSION

The inhibitory innervation of the IAS and the rectoanal inhibitory reflex are mediated by NO and the rectoanal inhibitory reflex requires an intact network of ICC in the IAS. Thus both loss of nitrergic innervation and deficiency of ICC lead to impaired anal relaxation and may play an important role in rectal evacuation disorders.

Assessment of the rectoanal inhibitory reflex in preterm infants with delayed meconium passage

BACKGROUND

There is an inverse relationship between gestational age, birth weight and the time of first neonatal bowel movement. The authors hypothesized that delayed passage of meconium might result from a delayed maturation of the recto-anal inhibitory reflex (RAIR) in premature infants.

OBJECTIVE

To evaluate whether the RAIR is absent in very preterm infants 28-32 weeks postmenstrual age with delayed meconium production.

STUDY DESIGN

Anorectal manometry was performed in 10 preterm infants (seven male) with delayed meconium production (no meconium in the first 48 hours). Median postmenstrual age was 30 weeks (28-31 weeks). Birth weight ranged from 780 to 1930 g (median, 1395 g). A micromanometric assembly (outer diameter, 2.0 mm) was used which incorporated a 1.5-cm-long sleeve sensor for measurement of resting anal sphincter pressure and relaxation. Four side-holes recorded anal and rectal pressures. Rectal distension was performed with direct air insufflation to elicit the RAIR.

RESULTS

The time from birth to passage of meconium ranged from 48 to 105 hours (median, 82 hours). The mean anal sphincter pressure, rectal pressure, and anal sphincter oscillation frequency were 22.0 +/- 5.0 mm Hg, 6.9 +/- 2.0 mm Hg, and 9.8 +/- 1.9/min, respectively. A normal RAIR was elicited in all infants.

CONCLUSION

Anorectal manometry recordings in premature infants with delayed passage of meconium showed normal anorectal pressures and a normal RAIR, suggesting that delayed meconium passage is not related to the absence of a RAIR.

PEG 3350 (Transipeg) versus lactulose in the treatment of childhood functional constipation: a double blind, randomised, controlled, multicentre trial

BACKGROUND

Recently, polyethylene glycol (PEG 3350) has been suggested as a good alternative laxative to lactulose as a treatment option in paediatric constipation. However, no large randomised controlled trials exist evaluating the efficacy of either laxative.

AIMS

To compare PEG 3350 (Transipeg: polyethylene glycol with electrolytes) with lactulose in paediatric constipation and evaluate clinical efficacy/side effects.

PATIENTS

One hundred patients (aged 6 months-15 years) with paediatric constipation were included in an eight week double blinded, randomised, controlled trial.

METHODS

After faecal disimpaction, patients <6 years of age received PEG 3350 (2.95 g/sachet) or lactulose (6 g/sachet) while children > or =6 years started with 2 sachets/day. Primary outcome measures were: defecation and encopresis frequency/week and successful treatment after eight weeks. Success was defined as a defecation frequency > or =3/week and encopresis < or =1 every two weeks. Secondary outcome measures were side effects after eight weeks of treatment.

RESULTS

A total of 91 patients (49 male) completed the study. A significant increase in defecation frequency (PEG 3350: 3 pre v 7 post treatment/week; lactulose: 3 pre v 6 post/week) and a significant decrease in encopresis frequency (PEG 3350: 10 pre v 3 post/week; lactulose: 8 pre v 3 post/week) was found in both groups (NS). However, success was significantly higher in the PEG group (56%) compared with the lactulose group (29%). PEG 3350 patients reported less abdominal pain, straining, and pain at defecation than children using lactulose. However, bad taste was reported significantly more often in the PEG group.

CONCLUSIONS

PEG 3350 (0.26 (0.11) g/kg), compared with lactulose (0.66 (0.32) g/kg), provided a higher success rate with fewer side effects. PEG 3350 should be the laxative of first choice in childhood constipation.

Prognosis of constipation: clinical factors and colonic transit time

BACKGROUND

Measurement of colonic transit time (CTT) is sometimes used in the evaluation of patients with chronic constipation.

AIM

To investigate the relation between symptoms and CTT, and to assess the importance of symptoms and CTT in predicting outcome.

METHODS

Between 1995 and 2000, 169 consecutive patients (median age 8.4 years, 65% boys) fulfilling the criteria for constipation were enrolled. During the intervention and follow up period, all kept a diary to record symptoms. CTT was measured at entry to the study.

RESULTS

At entry, defecation frequency was lower in girls than in boys, while the frequency of encopresis episodes was higher in boys. CTT values were significantly higher in those with a low defecation frequency (< or =1/week) and a high frequency of encopresis (> or =2/day). However, 50% had CTT values within the normal range. Successful outcome occurred more often in those with a rectal impaction. CTT results <100 hours were not predictive of outcome. However, those with CTT >100 hours were less likely to have had a successful outcome.

CONCLUSION

The presence of a rectal impaction at presentation is associated with a better outcome at one year. A CTT >100 hours is associated with a poor outcome at one year.