Atresia of small intestine (Q46350)

Jejunoileal atresias and stenoses are major causes of neonatal intestinal obstruction. Atresia refers to a congenital obstruction with complete occlusion of the intestinal lumen. It accounts for 95% of obstructions. Four types of jejunoileal atresias are described. They can range from having a small area of blockage or web to missing large sections of the intestines. Intestinal atresia is one of the most frequent causes of bowel obstruction in the newborn. The ileal atresia is more common than jejunal atresia, and multiple foci are more common than isolated atresia. The most accepted theory regarding the etiology of jejunoileal atresia is that of an intrauterine vascular accident resulting in necrosis of the affected segment. Stenosis, on the other hand, refers to a partial occlusion with incomplete obstruction and accounts for the remaining 5% of cases. A stenosis has an intact mesentery and is a localised narrowing of the bowel. No loss of continuity of the lumen exists.