Small bowel and colonic atresias

Abstract Small bowel atresia occurs in about 1 in 5000 live births, with a tendency for prematurity. The survival rate is 90% and is determined by the length and function of the residual bowel. Atresias are classified according to the operative appearance, with the most severe being ‘apple peel’ (type 3b) and multiple atresias (type 4). Proximal atresias are often diagnosed on antenatal ultrasonography. Presentation at birth is determined by the level of the most proximal obstruction—vomiting is the predominant symptom for proximal atresias, whereas abdominal distension is seen more commonly with distal atresias. The main differential diagnoses are malrotation with volvulus, meconium ileus, and Hirschsprung disease. Resuscitation with fluids, nasogastric decompression, and antibiotics are commenced immediately and prior to surgery. The aim of surgery is to gain bowel continuity, although this can be challenging in the presence of perforation, as a consequence of the marked disparity in calibre of the bowel across the atresia, where there are multiple atresias, in association with gastroschisis, where the length of the residual bowel will lead to short gut syndrome, and later with complications of malabsorption and prolonged total parenteral nutrition. Colonic atresia is relatively rare.