Hirschsprung’s disease (HD) or aganglionic disease It is a congenital disease of complex inheritance in which several genes are involved. It affects about 1 in 5,000 newborns, being slightly more common in boys.
What happens is that there is an alteration of intestinal motility at the level of the last sections of the large intestine, the colon and the rectum. This alteration is due to the fact that the cells responsible for regulating bowel movements were not formed during development. As a result, faecal evacuation is difficult, stool accumulates and constipation appears.
About 30% of cases Hirschsprung disease It is associated with other congenital anomalies. It is important to detect these abnormalities as they are important in prognosis and in finding the genes involved. In 12% it appears in children with Down syndrome.
Pathogenesis of Hirschsprung’s disease
When the food we eat reaches the stomach, gastric juice is released with which the digestion of proteins begins. chyme is formed, which is a homogeneous substance that passes into the small intestine. Once there, substances continue to be released that facilitate nutrient absorption.
Intestinal wall movements are essential for chyme to travel through the digestive tract until it reaches the anus., which push the bolus forward. These movements, called peristaltic movements, are muscle contractions and relaxations of the intestinal wall that push chyme through the intestines.
The regulation of these movements is carried out by the cells of the nervous system. called ganglion cells. These cells are not only found in the intestines but are also found in the esophagus and stomach, forming a complex nerve network known as enteric nervous system.
In Hirschsprung’s disease the ganglion cells of the large intestine are not formed during embryonic development, so there are no peristaltic movements that drive the fecal mass. As a result, these accumulate in the rectum and constipation occurs in the newborn.
Additionally, some bacteria can proliferate through fecal impaction and develop infectious conditions such as colitis.
Types of Hirschsprung’s disease
Depending on the section of the large intestine lacking ganglion cells, different types of Hirschsprung’s disease (HD) are distinguished. They all have in common the lower extremity, which is the internal anal sphincter. In an ascending sense, the extension of aganglionic allows us to distinguish between:
- Hirschsprung’s disease of the short segment. It represents 80% of cases, in this case the involvement reaches the sigmoid colon, which is the section of the large intestine immediately before the rectum. There is within this type a variant called Hirschsprung’s disease of the ultrashort segment. In this case, only the last part of the rectum is affected.
- Long segment Hirschsprung disease. It affects 20% of patients and the absence of ganglion cells extends beyond the sigmoid colon. It can affect the entire colon (farmhouse HE) or even the entire intestine (Intestinal HD).
Hirschsprung’s disease clinic
The manifestations of HD will depend on the intestinal surface affected and possible complications. Symptoms usually appear in the first months of life.
First, the clinical suspicion is given by the presence of constipation in the newborn. At birth, the nutrients that the baby had during pregnancy are excreted in the form of meconium. This expulsion must occur in the first 48 hours of life.
90% of children with HD do not pass meconium in this interval. Also, although meconium elimination is adequate, subsequent constipation is almost constant in children with this disorder. Moreover, newborns will present a clinic of intestinal blockagecharacterized by:
- vomit
- Abdominal distention: The newborn’s abdomen swells due to fecal accumulation, which also increases the abdominal gas content.
In some cases the clinic is more serious, triggering a picture of enterocolitis, that is, an intestinal infection. This is due to the fact that abdominal distension alters the intestinal wall, in such a way as to facilitate the proliferation of microorganisms that will develop the condition. It is more frequent in cases associated with Down syndrome and can lead to the death of the newborn. In this case it will appear:
- Fever.
- Lethargy, the level of consciousness decreases, so the child is unresponsive.
- Diarrhea, sometimes bloody.
- Abdominal distention.
Diagnosis
The suspected diagnosis is given by the clinic we have mentioned. Hence, it is important to confirm the diagnosis to avoid complications such as enterocolitis. The tests used are:
- abdominal x-ray, which confirms the picture of the obstruction.
- opaque enema: provides much more information than X-rays, as it allows us to see the extent of the disease. To do this, contrast is introduced through the anus and its distribution in the digestive tract is observed with imaging techniques. It allows you to see the aganglionic segment, where the intestinal wall is narrowest. Also allows you to see the so-called transition zone, where the segment without ganglion cells ends. Also, a control test may be performed after 24 hours as there is usually a delay in contrast removal.
- rectal manometry: This test confirms the alteration of intestinal motility, as it measures the response of the muscles to different pressures.
- Biopsy: It is the test that confirms the diagnosis of Hirschsprung’s disease. A small tissue sample is taken and examined under a microscope. If your child has Hirschsprung’s disease there will be no ganglion cells.
Prognosis and treatment of Hirschsprung’s disease
The treatment consists of a surgery in which the segment devoid of ganglion cells is removed, subsequently joining the intestinal section healthy with the anus, to normalize the fecal evacuation. Once intervened, the prognosis is good even if complications appear in half of the cases. Among the most frequent complications are:
- enterocolitis, which, as we have said, is the major cause of mortality in children with this disorder.
- faecal incontinence, which usually normalizes in the first year after treatment.
- Constipation, which may make it necessary to perform control tests to rule out other associated intestinal alterations.
- enuresis or urinary incontinencewhich may require further intervention.
Summing up…
As the MSD Manual states: “Hirschsprung disease is a congenital anomaly of the innervation of the lower segments of the intestine, usually limited to the colon, causing partial or complete functional obstruction” and, fortunately, can be repaired surgically and It should be noted that the prognosis after the operation is good.
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