Hirschsprung’s disease (HD) is also referred to as congenital aganglionic megacolon or meconium plug syndrome. Meconium plug syndrome is a broader diagnosis that correlates with a 13% incidence of Hirschsprung’s (Keckler et al., 2008). HD is most often found in the sigmoid colon of the large intestine preventing normal contraction of the affected area and subsequently normal expulsion of stool.
HD is a congenital disease in which ganglion nerve cells in the myenteric and submucosal plexi responsible for peristalsis and smooth muscle movement of the gut are absent from the intestine. This results from failure of the ganglion cells to migrate in a craniocaudal direction during the fifth through the 12th week of gestation (Keckler et al., 2008). As a result, there is a continual state of contraction of the aganglionic segment of bowel and the internal anal sphincter preventing normal expulsion of stool.
Short-segment HD is defined by the absence of nerve cells in the sigmoid colon (Keckler et al., 2008). In long-segment disease, there is an absence of nerve cells throughout most or all of the large intestines, occasionally part of the small intestine, and rarely the entire intestinal tract. The proximal bowel subsequently becomes dilated because of normal function in an effort to pass stool. The incidence is approximately one in 5,000 live births. Occurrence of this disease is a 4:1 male to female ratio (Moore, 2016). HD accounts for 20% to 25% of intestinal obstruction in the neonatal period.
Historically, this was a fatal disease. In 1886, Hirschsprung, a Danish pediatrician, presented two cases of infants at the Berlin Conference of German Society Pediatrics (Sergi, 2015). The infants’ similar symptoms included absence of spontaneous bowel movements, abdominal distention, and episodes of diarrhea. Treatment consisted of laxatives and daily enemas. Both children died. The autopsies showed rectal narrowing, dilated loops of bowel as well as some ulceration of the mucosa associated with thickening of the bowel wall (Sergi, 2015).
Significant HD research looking at the enteric nervous system (ENS) has been the focus of developmental neurobiologists and geneticists (Heanue & Pachnis, 2007; Moore, 2016). The ENS is the part of the parasympathetic nervous system that regulates smooth muscle movements and peristalsis of the gut. Developmental neurobiologists have been uncovering the molecular process of the migration, proliferation, and differentiation of neural crest cells responsible for the creation of the normal ENS. Geneticists have found a number of genetic expressions related to the development of HD. Biologic and genetic advances in HD have brought the focus to exploration for ENS stem cells.
Clinical presentation of HD may occur from early in the neonatal period to 2 or 3 years of life and beyond. Older children often present with chronic constipation or enterocolitis. However, in 80% to 90% of cases, symptoms occur in the neonatal period (Barksdale, Chwals, Magnuson, & Parry, 2011).