Sensitivity and Specificity of Anorectal Manometry in the Differential Diagnosis of Chronic Constipation in Children

BACKGROUND AND OBJECTIVE: Constipation is one of the most common reasons a child is referred to a pediatric gastroenterologist. In the vast majority no structural, endocrine, or metabolic etiology is identified and constipation called functional or idiopathic. The aim of this study was to evaluate the role of anorectal monometry in differentiating functional constipation from Hirschprung’s disease in children.METHODS: This cross sectional study was performed on 69 children aged 6 months– 13 years with chronic constipation, who didn’t response after suitable therapy during one year in children’s Hospital Medical Center. All of children underwent un-prepared contrast enema, considering: transition-zone, retained contrast after 24hr and abnormality of rectal diameter. Rectal biopsy was performed in patients with negative RAIR and suspected to hirschsprung’s disease, and data was analyzed. FINDINGS: Sixty nine children with age range 6 months- 13 years (mean age of 53.1±14 months) including 37 girls (53.62%) and 32 boys (46.38%) were studied. Rectoanal inhibitory reflex (RAIR) was present in 54 of the 69 patients (78.26%), and 15 cases (21.73%) with a negative (RAIR), underwent rectal biopsy. In which showed absence of the ganglion cells and intestinal neuronal dysplasia in 13 cases, that was compatible with Hirschsprung’s disease. Rectal manometry was again performed for 2 remained patients who had shown to have normal ganglion cell in their last rectal biopsy, and normal RIAR was determined. Sensitivity, specificity, positive and negative predictive value of the manometric test for diagnosis of Hirschprung’s diseases were 100%, 96%, 88% and 100%, respectively. CONCLUSION: The results of this study showed that anorectal manometry is the suitable method for diagnosis of functional constipation from Hirschprung’s disease in children. Rectal manometry is recommended before rectal biopsy for all children with refractory chronic constipation who are suspected to have Hirschsprung’s disease