I. Overview
In 1886, Dr. Harald Hirschsprung of Denmark first reported 2 cases in Berlin, which were named congenital megacolon because of the significant dilatation of the colon, and were called Hirschsprung’s Disease (HD) in honor of the discoverer.
Incidence (Incidence) is about 1:4000, gender: male:female = 4:1
II. Pathological classification
1, congenital megacolon is mainly based on the pathology of the lesion of the intestinal canal myenteric ganglion cell deficiency, also known as Aganglionosis. Guo Junbin, Department of Pediatric Surgery, Second Affiliated Hospital of Nanjing Medical University
2. Principle of occurrence: neural crest neuroblastoma cells develop along the gastrointestinal tube from the head to the tail, and the migration of enteric ganglion cells is interrupted in the process, and the distal enteric ganglion cells are absent. The smooth muscle of the diseased intestinal canal continues to contract, and spastic intestinal obstruction (non-organic intestinal stricture) occurs. The recto-anal reflex ring is interrupted, and it cannot induce rectal contraction and internal sphincter flaccidity, disappearance of bowel movement and constipation, feces cannot be excreted, and the proximal normal intestinal canal is compensated by fecal stasis and vigorous peristalsis to expand and hypertrophy, forming a huge dilated intestinal segment.
3.According to the length of the intestinal segment without ganglion cells, it is divided into
(1) Common type (common type) megacolon (75%): lesions are limited to rectum and sigmoid colon.
(2) Short-segment megacolon (8%): lesions are limited to 3-4 cm of the terminal rectum.
(3) Long-segment megacolon (14%): the lesion reaches above the splenic flexure of the colon, or even the whole colon.
(4) Special type of megacolon: rarely, the lesion involves the whole colon and the end of ileum.
Clinical manifestations
1.Neonatal period: acute low-level incomplete intestinal obstruction
(1) Delayed defecation after birth, >24-48 hours
(2) Abdominal distension with vomiting
(3) constipation, anal finger diagnosis and bowel lavage can help relieve symptoms
(4) Rarely combined with megacolon enterocolitis, resulting in megacolon crisis
(5) Other: wasting, malnutrition
2.Infancy and childhood
Features: subacute or chronic low-level incomplete bowel obstruction, manifested as recurrent constipation with progressive increase in abdominal distension.
(1) A history of delayed defecation after birth, and then recurrent constipation gradually worsens, with defecation once a week or even once every half month. The patient cannot defecate on his own and often relies on bowel cleansing or corkage to maintain defecation.
(2) Progressive increase of abdominal distension, huge intestinal shape can be seen, and sometimes huge fecal mass (fecal stone) can be palpated, which can be easily misdiagnosed as abdominal tumor.
(3) Growth retardation and malnutrition
(4) Anal finger diagnosis: can stimulate defecation, sometimes can be palpated huge fecal masses
(5) Barium enema: it can show the length of the spastic intestinal segment and the degree and extent of colonic dilatation, and determine the type of giant colonic lesion
(6) rectal anorectal manometry: the normal rectal anorectal reflex disappears, which is important to determine the diagnosis
(7) rectal biopsy (Biopsy): HE conventional pathology: disappearance of ganglion cells in the submucosa; histochemical staining: strong positive for acetylcholinesterase (AchE)
IV. Diagnosis
1History: delayed defecation, recurrent abdominal distension and constipation, progressive aggravation
2 Ancillary tests: A-R manometry: disappearance of rectal anal canal relaxation reflex; barium enema with typical megacolon changes
3 The above cannot confirm the diagnosis, rectal mucosal tissue biopsy: H E: disappearance of enteric ganglion cells, histochemistry: acetylcholinesterase strong positive
V. Treatment
1, treatment principles: surgical treatment is the main, resection of diseased intestinal segments
2.Pre-operative preparation.
(1) Bowel washing: isotonic saline bowel washing, siphoning method.
(2) anal sphincter and laxative.
(3) application of laxatives if necessary
3.Surgical treatment: radical surgery, removal of ganglion cell-free intestinal segments
Age: can be performed in the neonatal period, if combined with severe small bowel colitis, or long segmental giant colon, etc., colostomy first
4.Postoperative complications
(1) Immediate complications: anastomotic infection and leakage; urinary retention; small bowel colitis
(2) Middle and long term complications: anastomotic stenosis, recurrence of constipation; damage to the internal anal sphincter, defecation and incontinence.