PED Case 1: Gastroschisis

Rajashree Vyas, MD and Nina B. Klionsky, MD

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Imaging Sciences URMC 2008
Publication Date: 2009-06-04

History

Pre-term neonate at 34 6/7 weeks gestation delivered by cesarean section. History of polyhydramnios and gastroschisis on prenatal ultrasonography. Positive history of maternal marijuana/cocaine abuse during pregnancy.

Findings

Supine AP babygram demonstrates a large soft tissue opacity overlying the left hemipelvis. It has a small amount of gas within (black arrowheads). Tip of the Replogle tube projects over this opacity. A smaller tubular opacity with gas within is noted adjacent to the left femur representing a free loop of bowel (black arrow). The white arrow marks the umbilical cord. No associated radiographic abnormalities were noted.

Diagnosis

Gastroschisis

DDx

Gastroschisis

• Rupture of ventral abdominal wall after rotation and return of midgut into peritoneal cavity
• Lacks peritoneal sac
• Defect is para-umbilical, usually right sided.
• Normal position of umbilicus and cord insertion
• No associated anomalies
• Prenatal US shows free floating bowel loops within amniotic cavity. Normal cord insertion.

Omphalocele

• Failure of fusion of lateral folds. Midgut fails to return within the peritoneal cavity by 10th week of intrauterine life.
• Well-contained within peritoneal sac. In rare cases, a ruptured omphalocele (Figure 2) may present a diagnostic dilemma.
• Defect is umbilical
• Umbilicus and cord insertion displaced secondary to herniated contents
• Associated anomalies, usually cardiac in origin
• Prenatal US shows contained herniation of bowel loops with cord insertion at the dome of the sac

Cloacal extrophy is a severe malformation associated with bladder extrophy, omphalocele and epispadias. There may be associated pubic diastasis and spinal dysraphism.

Discussion

Gastroschisis is defined as protrusion of the stomach, midgut and occasionally the urinary tract through a paraumbilical defect in the ventral abdominal wall. It occurs secondary to (probably ischemic) rupture of the anterior abdominal wall after rotation and return of the midgut into the peritoneal cavity. Hence, it lacks a peritoneal sac and presents as free floating bowel loops within the amniotic cavity on prenatal ultrasonography.

On physical examination, the defect is usually 2-5 cm in length, right paraumbilical with normally positioned umbilicus and cord insertion. Children with gastroschisis are often born prematurely. Gastroschisis occurs twice as common as omphaloceles. Prenatal ultrasonography can aid differentiation between gastroschisis and omphaloceles.

The prognosis is excellent after closure of the defect. However, since amniotic fluid is considered toxic to bowel loops, these neonates are predisposed to bowel motility disorders presenting as multiple episodes of pseudoobstruction.

References

1. Donnelly LF. Fundamentals of Pediatric Radiology, WB Saunders, 2001, Chapter 5, pg 110.
2. Brant WE, Helms CA. Fundamentals of Diagnostic Radiology, 2nd ed., Lippincott Williams & Wilkins, 1999, Chapter 38, pg 903.
3. Blickman H. Pediatric Radiology: the Requisites, 2nd ed., CV Mosby, 1998, Chapter 4, pgs 107-108.