Chronic constipation - Pediatric Surgery

Chronic constipation - Pediatric Surgery Constipation . Hirschsprung's Disease, Aganglionosis, Congenital Megacolon . click the images for more details   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. 2. Constipation is a possible cause of obstructive ileus in the newborn. 3. If the diagnosis and treatment of Hirschsprung's disease is missed, there is the danger of life-threatening complications such as enterocolitis and toxic megacolon, failure to thrive and impairment of quality of life. 4. Hirschsprung's disease can be permanently cured by surgery.   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. The clinical presentation depends on the age of the patient and the nutrition: In newborns, the symptoms and signs are often insignificant; delay of passing the first stool beyond 36 hours, or passing in minute portions over a relatively long time; or less frequently, a life-threatening acute abdomen and general signs following an obstructive ileus, spontaneous perforation of the colon or an enterocolitis. In infants, mainly a constipation which becomes obvious on the transition from breast-feeding to feeding of an adapted milk. Prior to constipation, there is a tendency of abdominal distension, infrequent passage of winds and somewhat malodorous stools in spite of breast-feeding. In toddlers and schoolchildren, there is a distended abdomen and the failure to thrive. In the ultrashort or in total aganglionosis the clinical presentation may be misleading. 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. Contrast enema radiography is performed for the diagnosis and mainly for the localization of the transitional zone of aganglionosis. Anorectal manometry is performed to detect or verify an internal sphincteric achalasia. Submucosal suction or full-thickness biopsy is performed for the diagnosis and differential diagnosis (of other disorders of innervation). The latter is obtained either during surgery, or laparoscopically. 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: a) that all aganglionic parts of the intestine be removed; b) the removal and postoperative examination of a part of the intestine beyond the transitional zone (adjacent zone with hypoganglionosis or with neuronal colonic dysplasia); c) therapeutic consideration of the achalasia, for instance with intraoperative bouginage; d) regular follow-ups up to puberty by a pediatric surgeon. Today these operations may also be performed as minimally invasive procedures from the 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.