Constipation Hirschsprung's Disease, Aganglionosis, Congenital Megacolon |
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Incidence | |
Relatively frequent malformation with 1 in 3000-5000 newborns. In some types of Hirschsprung's disease there is a familiarity. | |
Clinical significance | |
1.
In 5 to 10 % of children with a constipation a pathoanatomical cause is
present. | |
Etiology | Illustrations |
There is an absence of ganglion cells in the myenteric and submucous plexus, a hyperplasia of submucous parasympathetical nerve fibers, and a decrease in neuroendocrine cells proximal to the anus over a variable distance upwards. Mainly in total colonic aganglionosis there is a sex-linked heritage with variable penetration. Mutations of the RET protooncogene in chromosome 10 and the endothelin-B receptor gene in chromosome 13 play an important role. | show details |
Pathology, anatomical types | Illustrations |
In more than 70 % the so-called classic type of Hirschsprung's disease is present with transition from the aganglionic rectum to the orally normal innervated intestinal tract at the level of the rectosigmoid flexure. If the level of the transition zone is very low (aganglionosis up to 3 centimeters above the anocutaneous line) the type of aganglionosis is called ultrashort, and if the transition zone lies beyond the left colonic flexure it is a long type. In total aganglionosis (Zuelzer-Wilson Syndrome) the whole colon without or with a variable length of small bowel up to the stomach is involved. | show details |
Pathophysiology 1 | Illustrations |
The involved part of the intestine exhibits no regular peristalsis, leading to an obstruction of stools and winds although the lumen of the involved bowel is open. The orally located normal intestine develops a hypertrophy of the muscles and a dilatation thereafter. This secondary dilatation is called megacolon although it is not the site of the disease. | show details |
Pathophysiology 2 | Illustrations |
Achalasia of the sphincter internus muscle. During the start of the mechanism of defecation there is no relaxation reflex of the internal sphincteric muscle, leading to further obstruction. | show details |
Pathophysiology 3 | Illustrations |
The stasis of the intestinal content and a locally diminished infection immunity may lead to enterocolitis which is the main cause of mortality in the first year of life. | show details |
Clinical presentation (history, findings, clinical skills) | Illustrations |
Based on the diminished motility of the intestine a prenatal diagnosis of Hirschsprung's disease may be
suspected. | show details |
Natural history | Illustration |
Constipation, failure to thrive, reduced nutritional condition and continuous danger of toxic megacolon. | show details |
Differential diagnosis | Illustrations |
Depending on age and clinical presentation: obstructive ileus mainly in the first year of life. Beyond early infancy: constipation, distended abdomen and failure to thrive for various reasons. | show details |
Work-up examinations | Illustrations |
The work-up
examinations should rest on three pillars because a single examination
may yield mainly false-negative results depending on
the age of the patient, the technique of examination, and the experience
of the examiner. | show details |
Therapy 1 | Illustrations |
Except for newborns with spontaneous colonic perforation or severe enterocolitis, irrigations with normal saline solution at least once to twice a day by the parents, and if possible breast-feeding up to the pull-through procedure or, alternatively, a diverting colostomy. | show details |
Therapy 2 | Illustrations |
The pull-through
procedure of Svenson-Grob performed at age of 4 to 6 months of life is
one of many possible operations which are also performed at an ealier
age. Of importance are: | show details |
Prognosis | |
Mortality is 5 % or less. Longterm follow-ups by experienced pediatric surgeons show that constipation, encopresis and enuresis, diarrhoea and enterocolitis may occur in 10 to 15 %, and that usually no fecal incontinence, no distinct disturbances of bladder voiding and erection do occur at puberty.
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