What is Hirschsprung’s disease?
The so-called Hirschsprung’s disease is a typical surgical disease of childhood in which a severe genetically triggered nervous motility disorder of the intestine is present. In the majority, boys are more frequently affected than girls. It occurs in approximately 1:5000 births. In the diseased intestinal segment, the immigration of ganglion cells was absent during development, and they are absent. The non-colonized intestinal segment is constricted, cannot dilate, and sufficient propulsive peristaltic waves are absent. Usually, i.e. in about 75-80% of patients, Hirschsprung’s disease affects the rectum, medically called the rectosigmoid.
The disease may affect only distal portions of the rectum as the so-called “the short form” or, much more rarely, the entire colon as the “the long form”. In addition, the absence of the recto-anal reflex (no automatic opening of the internal sphincter when stool is to be deposited) and functionally the permanent narrowing of the anal canal, called “anal sphincter achalasia” is part of the typical clinical picture. Severe intestinal inflammation (enterocolitis) may develop because of the stool passage disorder. The untreated disease can quickly lead to a life-threatening situation.
What are the first symptoms of this disease and how is the diagnosis made?
As a rule, constipation with considerable passage disturbance and significantly delayed meconium excretion (neonatal stool) within the first 48 hours of life is present from birth. The symptoms of subileus or ileus are prominent and there is a distended, bulging abdomen and even greenish vomiting. When an intestinal tube is inserted, which bridges the non-functioning rectum, the stool is emptied “explosively”. With shorter aganglionic segments, malnutrition develops associated with a severely bulging abdomen.
Diagnosis includes colon contrast enema one prior bowel evacuation (unprepared diagnostic irrigoscopy). The examination shows a typical picture with a narrow rectum of the cone-shaped transition zone and the dilated stool-filled intestine, i.e., regularly populated with ganglion cells. The still valid diagnostical “gold standard” is the histological specimen of the intestinal wall biopsy, where the missing ganglion cells and only many pathologically thickened nerve fiber bundles are detected. In addition, rectal manometry can show the absence of the rectoanal reflex.
Is it possible for Hirschsprung’s disease to progress with complications?
As a result of the impaired intestinal function, in addition to malnutrition and chronic constipation, up to half of the affected patients develop severe intestinal inflammation (enterocolitis), which can be accompanied by toxic intestinal paralysis and life-threatening sepsis. As a result of the impaired intestinal function, in addition to malnutrition and chronic constipation, up to half of the affected patients develop severe intestinal inflammation (enterocolitis), which can be accompanied by toxic intestinal paralysis and life-threatening sepsis. Increased colonization with pathogenic intestinal bacteria (Clostridium difficile, Staph. aureus, anaerobes, coliform bacteria, rotaviruses) is found in the intestinal sections dilated by stool. As an additional symptom, patients in these cases develop high fever. To avoid this critical complication, surgical removal of the non-functioning aganglionic intestinal segment as early as possible is recommended. In patients who have already undergone surgery, there is an increased risk of enterocolitis if a new stool stasis is caused by an unfavorable surgical technique.
Are some children more predisposed to this disease and what are the risk factors? Can it be prevented?
Hirschsprung’s disease is associated with complex genetic alterations where multiple gene mutations have been demonstrated to be disease-associated. The most important identified gene with a mutation is the RET gene. In addition, other mutations in at least 6 different genes seem to be of importance. The genetics of Hirschsprung disease are so complex that the presence of a known disease-causing mutation does not necessarily result in phenotypic Hirschsprung disease. Not all mutation carriers develop the disease. 90% of Hirschsprung’s disease occurs as an isolated disease. 7-10% of patients already have another case in the family. Preventive measures to prevent this disease are not yet known.
What is the treatment?
In addition to bowel irrigation and bowel evacuation aids with a bowel tube, a temporary artificial bowel outlet (colostomy) may also be necessary for successful treatment.
The aim is to surgically remove the non-functioning section of bowel and thus enable regular passage of stool. Because the rectum, including the anal canal, is functionally diseased, it is important to connect the healthy intestine as closely as possible to the anal canal after removing diseased sections of the intestine (coloanal anastomosis – surgery according to SOAVE – BOLEY).
Today, this operation can be performed minimally invasively through the anus without opening the abdomen. It is essential that the anastomosis is close to the anal canal, whereby the anoderm of the anus is preserved as the important sensitive zone. If this anastomosis is set too high, leaving a few centimetres of diseased bowel above the anal canal, there is a significant risk of postoperative recurrence of constipation and enterocolitis. The healthy intestine cannot overcome the resistance of the diseased intestinal remnant left behind.
This also includes the ever-present lack of relaxation reflex of the internal sphincter muscles. Intramuscular injections of botulinum toxin can be used as a treatment, which may have to be repeated at intervals of several months. Alternatively, the splitting of the internal sphincter muscle (sphincter myotomy) was recommended in the past, but this is confronted with the problem of possible reduced faecal continence.
How common is the disease?
It occurs in approximately 1:5000 births.