Hirschsprung's disease (HD) is usually diagnosed in the newborn period and early infancy. The common presentation of HD in newborns consists of a history of delayed passage of meconium within the first 48 hours of life. The differential diagnosis in newborns is one of the clinical challenges of this disorder. A number of medical conditions which cause functional obstruction of the intestines are easily excluded. Neonates with meconium ileus, meconium plug syndrome, distal ileal atresia and low imperforate anus often present in a manner similar to those with HD in the first few days of life. Abdominal radiographs may help to diagnose complete obstruction such as intestinal atresia. Microcolon on contrastenema can be shown in cases with total colonic aganglionosis, ileal atresia or meconium ileus. Suction rectal biopsy or frozen section biopsy at operation is essential for differential diagnosis in such cases. HD is also considered in any child who has a history of constipation regardless of age. Older children with functional constipation may have symptoms that resemble those of HD and contrast enema is usually diagnostic. However, children with other motility disorders generally referred to as chronic idiopathic intestinal pseudoobstruction present with very similar symptoms and radiographic findings. These disorders are classified according to their histologic characteristics.; visceral myopathy, visceral neuropathy, intestinal neuronal dysplasia (IND), hypoganglionosis, immature ganglia, internal sphincter achalasia. Therefore, the workup for motility disorders should include rectal biopsy not only to confirm the presence of ganglion cells but also evaluate the other pathologic conditions.
