Causes of Hirschsprung's disease in adults

We all know that congenital megacolon mainly occurs in the neonatal period, but it does not exclude adults. There are also many adults whose physical symptoms are not obvious in infancy or even childhood, and only after adulthood, they are affected by many factors and the disease breaks out. So what are the causes of congenital megacolon in adults?

Treatment of Hirschsprung's disease includes conservative treatment and surgical treatment. Once diagnosed, radical resection of Hirschsprung's disease is necessary to relieve symptoms sooner or later. Conservative treatment is suitable for mild clinical manifestations, incomplete diagnosis and preoperative preparation. The main method is to stimulate the anus and rectum with soap cream and suppositories, and use warm saline enema to defecate when necessary.

Surgical treatment includes transitional surgery (enterostomy) and definitive surgery. Enterostomy is usually used for patients with enterocolitis, intestinal perforation or malnutrition who cannot tolerate major surgery. After comprehensive improvement, radical surgery is performed. Radical surgery should completely remove the diseased narrow intestinal segment and restore intestinal continuity.

Due to improvements in surgical techniques and monitoring, children with Hirschsprung's disease 6 months or earlier can safely undergo radical surgery, thus avoiding complications such as enterocolitis and malnutrition. In addition, children should be trained to have bowel habits after surgery, and anal dilation should be performed regularly under the guidance of a doctor to consolidate the long-term effect.

The prognosis of this disease is poor due to malnutrition or colonic crisis. According to many reports, the mortality rate at 6 months is 50%-70%. Newborns often die from complications of enteritis. It is rare for adults to live without treatment; even if they live as adults, they may die from colonic crisis at any time. In recent years, the survival rate of patients with congenital megacolon has improved significantly. Due to delayed diagnosis of enterocolitis and sepsis, as well as widespread pancolonic ganglioneurolysis, the mortality rate of patients with proximal small intestine is low. Many deaths are due to Down syndrome.

Children with preoperative enterocolitis may have complications following colostomy and extraction. Overall, patient survival is over 90%. Long-term follow-up is very important. Most patients (>96%) have control of their stool, 2%-3% have fecal incontinence, and fecal incontinence is rare (<1%). Some patients may be constipated (10%-20%). However, a high-fiber diet and stool softeners tend to improve symptoms in most patients, which can gradually improve with age.

Causes of Hirschsprung's disease:

1. Traditional Chinese Medicine

The disease is caused by insufficient congenital endowment, malnutrition of the mother during pregnancy, premature birth or incomplete development of the embryo, which leads to congenital defects, weak internal organs or malformations of internal organs after the fetus is born.

2. Modern Medicine

1. Developmental disorders of tissues originating from the neural crest

This disease is a disease caused by a developmental disorder of tissue originating from the neural crest. Embryological studies have confirmed that from the fifth week of the embryo, the neural tube protoganglion cells derived from the neural crest migrate from the head to the tail along the vagus nerve fibers. The entire migration process is completed by the 12th week of the embryo. Therefore, aganglionosis is caused by a developmental arrest before the 12th week of the embryo. The earlier the arrest, the longer the aganglion cell-free intestinal segment. The rectum and sigmoid colon at the tail end are the last to be evolved by neuroblasts, so they are the most common lesion sites. Due to the complete absence or reduction of ganglion cells in the intestinal wall muscle layer and submucosal plexus, the diseased intestinal segment loses peristalsis and is often in a spasmodic state, forming a functional intestinal obstruction. Over time, the upper colon of the obstruction site expands and the intestinal wall thickens, forming congenital megacolon. As for the original cause of the developmental arrest, it may be caused by a motor neuron developmental disorder due to viral infection or other environmental factors (metabolic disorders, poisoning, etc.) in the early pregnancy of the mother.

2. Believe that it is related to genetic factors

Since Carter and Ward conducted a systematic study on the genetics of megacolon in the early 1950s, many scholars have published research results in this area. Zueher and Wilson reported that there were 6 patients among 12 siblings; Richordson and Brown described 7 sons of 3 patients with megacolon (fathers), 6 of whom had megacolon; Emanucl found that 5 children in a family all had megacolon, and one of the 3 children born to their mother after marriage with her second husband was also affected, so it supports genetic factors. However, there are different views on the inheritance mode; Passarge believes that there is less evidence that it conforms to simple Mendelian inheritance, so it is believed that it may be a heterogeneous pathogen and may be a sex-modified polygenic inheritance, that is, the genetic threshold is different between sexes. Compared with the general population, the risk of female patients with congenital megacolon and their offspring to develop this disease increases by 360 times; the risk of male patients with congenital megacolon and their offspring to develop this disease increases by 130 times. Emanucl and Salmon believe that the genetic factor of megacolon may lie in the abnormality of the 21st pair of chromosomes. In summary, megacolon is a polygenic hereditary disease with genetic heterogeneity.

3. Environmental factors

The so-called environmental factors include the influence of all non-genetic factors that play a role before birth (in the womb), during birth and after birth. Touloukian et al. reported a case of a premature infant who developed megacolon due to hypoxia. He believed that hypoxia could lead to the redistribution of capillary circulation, and blood would leave the abdominal viscera to protect the heart, brain and other organs related to life, thus causing a serious "selective circulation disorder", which would change the function of the premature infant's immature distal colon ganglion cells and then cause them to disappear. Ehrenpries confirmed that surgical injury can cause megacolon. Lane and Todd reported 26 cases of adults with megacolon in 1977. Others have used physical and chemical methods to cause temporary ischemia of the colon, which can successfully induce experimental animals to have megacolon similar to that of humans. Therefore, scholars have now acknowledged that acquired megacolon caused by environmental factors exists.