Gastroschisis

Abstract

After completing this article, readers should be able to: 1. Describe normal embryology and various theories contributing to derangements in development leading to gastroschisis. 2. Delineate several theories regarding the pathogenesis of gastroschisis. 3. Explain the environmental and other risk factors linked to gastroschisis. 4. Describe the prevalence of gastroschisis in developed countries and various theories explaining it. Gastroschisis is a congenital anterior abdominal wall defect, adjacent and usually to the right of the umbilical cord insertion. It occurs as a small, full-thickness periumbilical cleft either immediately adjacent to the umbilicus or separated from it by a strip of skin. This results in herniation of the abdominal contents into the amniotic sac, usually just the small intestine, but sometimes also the stomach, colon, and ovaries (Figure⇓). The abdominal wall defect is relatively small compared with the size of the eviscerated bowel, which often develops walls that are matted and thickened with a fibrous peel. Gastroschisis has no covering sac and no associated syndromes. This differentiates it from an omphalocele, which usually is covered by a membranous sac and more frequently is associated with other structural and chromosomal anomalies (Table 1). In addition, although gastroschisis may be associated with gastrointestinal anomalies such as intestinal atresia, stenosis, and malrotation, it has a much better prognosis than omphalocele. Figure. Gastroschisis, resulting in herniation of the abdominal contents into the amniotic sac. | | Gastroschisis | Omphalocele | |:---------------------------:| ----------------------------- | ---------------------------------------------------------- | | Incidence | 1 in 10,000 (now increasing) | 1 in 5,000 | | Defect Location | Right paraumbilical | Central | | Covering Sac | Absent | Present (unless sac ruptured) | | Description | Free intestinal loops | Firm mass including bowel, liver, etc | | Associated With Prematurity | 50% to 60% | 10% to 20% | | Necrotizing Enterocolitis | Common (18%) | Uncommon | | Common Associated Anomalies | Gastrointestinal (10% to 25%) | Trisomy syndromes (30%) | | | Cardiac defects (20%) | | | Beckwith-Weidemann syndrome | | | Cryptorchidism (31%) | Bladder extrophy | | Prognosis | Excellent for small defect | Varies with associated anomalies | | Mortality | 5% to 10% | Varies with associated anomalies (80% with cardiac defect) | Table 1. Differences Between Gastroschisis and Omphalocele The term gastroschisis is derived from the Greek word laproschisis , meaning “bellycleft.” It was used in the 19th and early 20th centuries by teratologists to designate all abdominal wall defects. No clear distinctions were made between abdominal wall defects until 1953, when Moore and Stokes classified them based on their appearance at birth. They suggested that the term gastroschisis be reserved for those cases in which the …