[Anorectal manometry in the neonatal diagnosis of Hirschsprung's disease].

Objective: To determine the usefulness of anorectal manometry (AM) in neonatal screening for Hirschsprung's disease (HD).

Material And Methods: We review the anomanometric studies of 98 newborn (63 males and 35 females) with clinical suspicion of HD, noting the indications of AM, gestational age, weight, age in days at the test, and whether or not other diagnostic methods were performed. Studied at rest were the pressures (mmHg) in the rectal ampulla (RA), proximal anal canal (PAC), and distal anal canal (DAC), and, in the stimulation phase, the presence or absence of a recto-anal inhibitory reflex (RAIR). In patients with no RAIR, the study was repeated weekly until the end of the first month, and if there was still no RAIR a suction rectal biopsy (SRB) was performed. In these patients and those with signs of intestinal obstruction, a contrast enema was carried out.

Results: The indications of AM are: delayed meconium passage, abdominal distension, and/or vomiting in 61.5% of the patients, intestinal obstruction in 16%, constipation in 15.1%, and other causes in 7.4%. The mean gestational age was 35.59 +/- 4.59 weeks, and the weight 2518 +/- 912.91 g. The mean age at the first test was 15.08 +/- 11.33 days. A RAIR was observed at the first study in 65 patients (healthy 54, meconium plug 2, meconium ileus 2, intestinal neuronal dysplasia 1, false negative 1, and other diagnoses 6), and was absent in 27 (HD 20, small left colon syndrome 4, hypoganglionism 1, and false positives 2). In 6 patients the first study was considered invalid. Histological studies confirmed HD in 21 newborn, in 11 of whom the contrast enema showed a transition zone. There were no differences between healthy and HD newborn in the RA, PAC, or DAC resting pressures. The sensitivity of AM for the diagnosis of HD was 95% and its specificity 90.24%. The sensitivity and specificity of rectal biopsy were 100%. The sensitivity of contrast enema was 52.3%, and its specificity 78.6%.

Conclusions: AM is a simple and safe method with high sensitivity and specificity for the neonatal diagnosis of HD. We consider it indicated prior to SRB in every newborn with clinical suspicion of this disease.