A manometric assessment of anorectal pressures and its significance in the diagnosis of Hirschsprung's disease and idiopathic megacolon

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.

Encopresis and constipation in children

Chronic retentive constipation in children is common, often undertreated, and frequently resistant to standard treatment. A new understanding of abnormal defecation dynamics has evolved to complement the established medical behavior model of this condition. The primary care pediatrician is in an excellent position to facilitate prevention through counseling on normal bowel habits and early intervention. A comprehensive medical behavior intervention program can be supervised effectively by the pediatrician providing benefit to most patients. Those who are compliant with treatment and are resistant to intervention may benefit by extensive evaluation of anorectal dynamics and use of such teaching as biofeedback training.

Function of the anal sphincters after chronic radiation injury

Anorectal manometry was done in 10 men with chronic radiation proctitis and symptoms of urgency, frequency, and occasional incontinence of faeces. They were compared with 10 asymptomatic age and sex-matched controls. The maximum resting anal canal pressure and the physiological sphincter length were significantly lower (p less than 0.01) in the irradiated group. The rectosphincteric reflex was absent in one patient and showed abnormalities of recovery in four others, who had received radiotherapy. The squeeze pressure of the external sphincter was not significantly different. These results indicate that dysfunction of the internal anal sphincter may contribute to patients' anorectal symptoms after pelvic radiotherapy. Histological evidence suggests that damage to the myenteric plexus is mainly responsible. The manometric function of the external sphincter remains relatively unaffected.

Acetylcholinesterase activity in rectal mucosa and blood in the diagnosis of Hirschsprung's disease

Histochemical and biochemical examinations of rectal biopsy specimens were performed in 13 patients with Hirschsprung's disease and in seven with idiopathic constipation and no megacolon. Serum and erythrocyte acetylcholinesterase (AchE) activity in these two groups was compared with that in 30 normal controls. AchE staining of rectal biopsy specimens proved to be a reliable and convenient diagnostic approach in patients with Hirschsprung's disease. Biochemical assay of AchE activity in rectal biopsy specimens was also of value in the diagnosis, however, there was an overlap between Hirschsprung's disease and idiopathic constipation. Erythrocyte AchE activity correlated well with AchE activity in rectal biopsy specimens. Therefore, assays of erythrocyte AchE activity provided useful additional information, especially in screening tests for Hirschsprung's disease.

An assessment of anorectal motility in the management of adult megacolon

Anorectal motility measurements have been performed on 19 patients with adult megacolon and the results compared with 12 normal subjects. Adult Hirschsprung's disease (4 patients) was recognized by the absence of anal canal inhibition on rectal distension (normal mean inhibition 21.9 +/- 2.3 mmHg). Seven patients with non-Hirschsprung's megacolon (idiopathic) had an elevated anal pressure (mean 90.4 +/- 7.0 mmHg). These patients were treated with repeated anal dilatation. Eight further patients had normal anal canal pressures (mean 33.2 +/- 11.7 mmHg) and were treated with enemas and regular suppositories. Little overall clinical improvement resulted in this group and 1 patient underwent subtotal colectomy. Measurements of anorectal motility have been found to assist in the management of adult megacolon.