1994-10-18-11 Gastroschisis, left-sided, associated with persistent right umbilical vein © Levine www.FheFetus.net

*Department of Radiology, Beth Israel Hospital, 330 Brookline Ave, Boston, MA 02215-5491. Ph: 617-735-2561; Fax: 617-278-8212.

Department of Radiology, University of California, San Francisco

Gastroschisis

Synonyms: Paraomphalocele, laparoschisis, abdominoschisis.

Definition: Gastroschisis is a paraumbilical defect involving all layers of the abdominal wall. It is usually located to the right of a normal umbilical cord insertion site.

Prevalence: Around 2:10,000¹.

Etiology: Unknown.

Pathogenesis: A leading theory of the pathogenesis of gastroschisis is that there is abnormal involution of the umbilical vein. The umbilical veins early in gestation drain the evolving abdominal wall. By the sixth week of gestation, a progressive atrophy of the right umbilical vein typically begins. According to deVries, either premature atrophy or persistence of the right umbilical vein explains the localized right paraumbilical defect found in gastroschisis¹. If premature atrophy occurs prior to establishment of adequate secondary circulation from the aorta, ischemia will result. Another possibility is that abnormal persistence of the right umbilical vein could impair the development of normal replacement vessels, resulting in infarction of the surrounding tissues by the time the umbilical vein atrophies. Other theories suggest that gastroschisis is the result of interruption of the omphalomesenteric artery ², or gastroschisis evolves from rupture of the amniotic membrane at the base of an umbilical cord mass^3,4.

Associated anomalies: Gut malrotation and nonfixation of the bowel to the dorsal abdominal wall. Associated anomalies include intestinal ischemia and atresia. Congenital anomalies of other systems are uncommon.

Differential diagnosis: The main differential diagnosis is between gastroschisis and omphalocele. Omphalocele is a midline defect usually containing liver covered by a membrane with the cord inserting through the membranous covering^5,6. Omphalocele has a greater association with other chromosomal and structural anomalies than does gastroschisis. Other abdominal wall defects such as bladder exstrophy or amniotic band syndrome may resemble gastroschisis.

Prognosis: Prognosis is good with surgery in the neonatal period.

Recurrence risk: Rare⁷.

Management: Management includes screening for intrauterine growth retardation. In the postnatal period, surgery is performed for resection of necrotic bowel, repair of atresias, and primary or staged closure of the abdominal wall defect. Parenteral nutrition is supplied if needed.

Persistent right umbilical vein

Synonyms: None.

Definition: Persistent right umbilical vein.

Prevalence: Uncommon.

Etiology: Unknown.

Pathogenesis: In the developing fetus, the right umbilical vein normally regresses at six weeks gestation, leaving a single left umbilical vein¹. When the left umbilical vein regresses instead of the right, there is a persistent right umbilical vein.

Associated abnormalities: Persistent right umbilical vein is associated with a variety of severe congenital anomalies, including cardiovascular, gastrointestinal, genitourinary, and musculoskeletal ^8,9. When persistent right umbilical vein is noted as an isolated anomaly on prenatal sonography, it likely has no clinical significance¹⁰.

MESH Gastroschisis ICD9 756.7 BDE 0405 CDC 756.710

Case report

A 17-year-old woman was referred for prenatal sonography for evaluation of gastroschisis. Examination revealed a 24 week gestation with an abdominal wall defect located to the left of the umbilicus with bowel loops floating in the amniotic fluid, consistent with a left-sided gastroschisis (fig. 1). The intrahepatic portion of the umbilical vein was noted to be lateral to the gallbladder with the curve of the vein directed toward the stomach (fig. 2-3), consistent with persistent right umbilical vein.

Figure 1: Left-sided gastroschisis. Echogenic bowel loops are seen

Figure 2:  Persistent right umbilical vein. The umbilical vein (curved

Figure 3: Persistent right umbilical vein. The umbilical vein curves

Discussion

Gastroschisis is typically a small abdominal wall defect, located to the right of the umbilicus. A leading theory of the pathogenesis of right-sided gastroschisis is that abnormal circulation to the lateral body wall at its junction with the body stalk occurs during involution of the right umbilical vein¹. The location of the defect on the left side has been reported but is rare¹. The 1980 article by deVries mentioned two cases of left-sided gastroschisis associated with a persistent right umbilical vein¹. We report a third case with this association. The combination of left-sided gastroschisis with persistent right umbilical vein gives credence to the theory that the umbilical vein is involved in the pathogenesis of gastroschisis, and that an abnormality of the regression of the left umbilical vein is a factor in the development of left-sided gastroschisis.

References

1. deVries P. The pathogenesis of gastroschisis and omphalocele. J Pediatr Surg 1980;15:245.

2. Hoyme H, Higginbottom M, Jones K. The vascular pathogenesis of gastroschisis: intrauterine interruption of the omphalomesenteric artery. J Pediatr 1981;98:228-231.

3. Perrella R, Ragavendra N, Tessler F, et al. Fetal abdominal wall mass detected on prenatal sonography: gastroschisis vs. omphalocele. AJR 1991;157:1065-1068.

4. Shaw A. The myth of gastroschisis. J Pediatr Surg 1975;10:235-244.

5. Bond S, Harrison M, Filly R, et al. Severity of intestinal damage in gastroschisis::correlation with prenatal sonographic findings. J Pediatr Surg 1988; 23:520.

6. Redford D, McNay M, Whittle M. Gastroschisis and exomphalos: Precise diagnosis by mid pregnancy ultrasound. Br J Obstet Gynaecol 1985;92:54.

7. Goncalves L, Jeanty P. Ultrasound evaluation of fetal abdominal wall defects. In: Callen P, ed. Ultrasonography in obstetrics and gynecology. Philadelphia: WB Saunders, 1994

8. Jeanty P. Persistent right umbilical vein: an ominous prenatal finding? Radiology 1990;177:735-738.

9. Theander G, Karlsson S. Persistent right umbilical vein. Acta Radiol 1978;19:268-274.

10. Kirsch C, Feldstein V, Goldstein R, et al. Persistent right umbilical vein: a sonographic series with no associated fetal anomalies. American Roentgen Ray Society meeting. New Orleans, 1994.