Malformations Learning Materials

MALFORMATIONS Malformations can affect all levels of the digestive system. 1. At the level of the pharyngeal intestine and branchial region 1.1. Cervical cyst and fistula They result from a persistence of the cervical sinus which appears from the 6th week and which normally disappears completely, communication to the outside (fistula) is rare. 1.2. Thyroid-glossal duct cysts These are persistent residual pockets on the path of the thyroglossal duct, the persistence of a remnant of glandular parenchyma is possible giving an accessory thyroid gland. 2. At the level of the anterior primitive intestine 2.1. On the upper floor The malformations are secondary to anomalies in the individualization of the respiratory anlage: the most frequent are atresias (see glossary) of the esophagus accompanied or not by tracheoesophageal fistula; it can also be esophageal stenosis, a simple reduction in the caliber of the esophagus without an anomaly of the bronchial tree. 2.2. In the caudal part The most common malformation is pyloric stenosis, real surgical emergency in the first weeks of life due to blockage of transit and vomiting due to hypertrophy of the muscular layer of the wall which causes a reduction in the size of the lumen. Other malformations are rarer and result from abnormality of bile duct formation and fusion of pancreatic buds: bile duct atresia with dilatations of the bile ducts and postnatal jaundice annular pancreas often asymptomatic. 3. In the mid-primitive intestine The most common malformations are anomalies of the proximal end of the yolk duct: Meckel's diverticulum corresponds to the persistence of the area terminal of the vitelline duct in the form of a diverticulum adjoining the opening into the ileum, a few centimeters from the ileo-caecal junction. It can be the site of inflammation or even infection (clinical picture similar to acute appendicitis), Elsewhere there are anomalies relating to the junction zone of the vitelline canal with the umbilicus: persistence in the form of a flange (fibrous cord) which can prevent the cecum from tilting into the right iliac fossa, persistence of a residual cavity forming a cyst, or even canal remaining open towards the exterior after the section of the umbilical cord (omphalo-mesenteric fistula), Another malformation is the omphalocele which corresponds to a failure of reintegration of the intestinal loops which remain in the umbilical cord outside the abdominal cavity, covered by the peritoneum and the amniotic wall, Other malformations, which are rarer, are secondary to a lack of rotation with risk of volvulus or a reduction in caliber (atresia or stenosis) with risk of intestinal obstruction. Hirschsprung's disease or congenital megacolon is linked to a failure of development of the nerve cells of the colonic wall (Auerbach and Meissner plexus) giving a dilated colon with accumulation of feces which can lead to an obstruction syndrome. 4. In the posterior primitive intestine The most common malformations are anorectal atresias which can be located at different levels. They may or may not be associated with anal imperfection and may be accompanied by rectogenital fistulas (abnormal communication with the urethra in men or the vagina in women). These malformations can be corrected by surgical intervention, their screening is systematic at birth. Appendices Glossary :atresia: Defective development of a hollow organ accompanied by a reduction in caliber (maximum total closure of the light) diverticulum: Accessory outline appearing from an organ hollow and remaining attached (at least temporarily) to the latter. invaginations: Cellular expansion from a sheet or an organ developing in underlying tissue (within the initial limit).