Hirschsprung’s disease (HD) appears when there is an alteration of the motility of the large intestine, colon and the rectum. This alteration is due to the fact that the cells responsible for regulating intestinal movements have not been formed during embryonic development. As a consequence, fecal evacuation is affected, stools accumulate and constipation appears. Hirschsprung’s disease is more common than it seems, especially in children with Down syndrome. The disease, also known as intestinal aganglionism, is a congenital disease of complex origin in which several genes are involved. It affects approximately 1 in 5,000 newborns, most of them being male. In more than 31% of cases, HD is associated with other congenital disorders. It is crucial to detect these anomalies since they are important in the prognosis and in the search of the genes involved.
When the food we eat reaches the stomach, gastric juices are released, which is when digestion in the stomach begins. Chyme (mixture of gastric juices and food) is then formed and passes through the small intestine. Once there, the stomach continues to release substances that facilitate the absorption of nutrients. For the chyme to traverse the digestive tract to the anus, movements of the intestinal wall (peristalsis) are essential. These movements are waves of contractions and relaxations of the intestines that help push the chyme through until it reaches the anus where it is eventually evacuated. The regulation of these movements is performed by cells of the nervous system called ganglion cells. These cells are found in the intestine, the esophagus and stomach, forming a complex nerve network that is known as the enteric nervous system.
Depending on the section of the large intestine lacking ganglion cells, different types of Hirschsprung disease are known. All of them have the lower end of the bowels affected, specifically, the internal anal sphincter. The extension of intestinal aganglionism allows professionals to differentiate between:
– Short segment disease: It usually affects more than 79% of cases and involved the section of the large intestine known as the sigmoid colon, located just before the rectum.
– Long segment disease: It affects approximately 21% of patients and the absence of ganglion cells extends beyond the sigmoid colon. It can affect the entire colon or the entire intestine.
The severity and manifestations of HD will depend on the affected intestinal space and its possible complications. Symptoms usually appear in the first months of life. Clinical suspicion is given by the presence of constipation in the newborn. At birth, the nutrients the baby has had during pregnancy are expelled in the form of meconium. This expulsion takes place within the first 2 days of life. Studies show that 90% of children with HD do not eliminate meconium within these 2 days. In addition, subsequent constipation is almost constant in children who suffer from this disease.
Newborns with Hirschsprung’s disease will present intestinal obstruction characterized by vomiting, abdominal distension (the abdomen of the newborn swells due to fecal accumulation, also increasing the content of abdominal gas), fever, lethargy and diarrhea, sometimes with blood.
The diagnosis of this disease is based on observing the characteristic clinical picture mentioned above. To clear any doubts, it may be wise to perform a physical examination of the abdomen to confirm the accumulation of fecal matter. An endoscopy, when the bowels quiescence is an obvious red flag, is also very useful to help diagnose Hirschsprung’s disease.