Overview
Gastroschisis and exomphalos (also known as an omphalocele) are congenital abdominal wall defects characterised by herniation of the intestines out from the abdominal cavity. In exomphalos, the intestines are covered by a sac formed from the outpouching of the peritoneum. In gastroschisis, there is no covering sac.
Epidemiology
- Gastroschisis can affect up to 6 in 10,000 live births
- Gastroschisis is slightly more common in boys than girls
- Exomphalos can affect up to 1 in 5,000 to 1 in 10,000 live births
Risk Factors
- Maternal age:
- <20 years old is a risk factor for gastroschisis
- >35 years old is a risk factor for exomphalos
- Smoking
Associations
Gastroschisis
Associated abnormalities are less common in gastroschisis compared to exomphalos, however, there may be associated:
- Anencephaly
- Cleft lip and palate
- Atrial septal defect
- Intestinal atresia
- Gastro-oesophageal reflux
- Hirschsprung’s disease
Exomphalos
Exomphalos is associated with:
- Pentalogy of Cantrell – defects of the diaphragm, abdominal wall, pericardium, heart, and lower sternum
- Beckwith-Wiedemann syndrome – a congenital overgrowth syndrome characterised by acromegaly, macroglossia, and exomphalos
- Chromosomal abnormalities – trisomy 13 (Patau syndrome), 18 (Edwards syndrome), and 21 (Down’s syndrome)
Diagnosis
Congenital abdominal wall defects are usually identified on ultrasound scans in the antenatal period, seen as an abdominal mass outside of the abdominal wall. Other tests may include:
- Maternal serum alpha-fetoprotein:
- May be elevated due to protein loss from the intestines floating in amniotic fluid
- Karyotyping:
- To screen for chromosomal abnormalities as abdominal wall hernias are associated with some
Management
Overview
The overall aims of management include resuscitation, temperature maintenance, and stabilising the neonate before surgical correction. Timely management reduces the risk of additional fluid loss from the intestines, ischaemia, and infarction.
While the gut recovers, infants are generally fed via total parenteral nutrition (TPN).
Gastroschisis
Gastroschisis is a surgical emergency and requires immediate closure or coverage. Vaginal delivery may be possible, however, other complications such as intrauterine growth restriction may affect this.
Immediate management involves resuscitation and putting a sterile cover (clear bowel bag) over the herniated abdominal contents to prevent infection, heat loss, and fluid evaporation. Neonates undergo surgery immediately or within 5 days.
Exomphalos
The mode of delivery depends on the size of the defect. Small defects may be able to undergo vaginal delivery, however, caesarean sections may be indicated due to the risk of rupture. In general:
- Sac not ruptured: clear bowel bag placed over herniated contents and non-urgent staged repair
- Sac ruptured: treat as gastroschisis with immediate repair when possible
Complications
- Intestinal atresia – in around 15% of infants with gastroschisis due to ischaemia of the exposed gut
- Sepsis
- Poor nutrition and failure to thrive
- Necrotising enterocolitis
- Short bowel syndrome – if ischaemia occurs in the bowel in gastroschisis
- Complications of TPN – infection, hepatomegaly, and cholestasis
Prognosis
Overview
In general:
- The prognosis of gastroschisis and exomphalos depends on the severity of the defect and associated anomalies
- In both, intrauterine growth restriction and herniation of the liver are associated with a poorer prognosis
Gastroschisis
The majority of those with simple gastroschisis (intact bowel with no ischaemia) recover after a month in hospital and go on to live normal lives. However, those with complex gastroschisis (bowel perforation, necrosis, or atresia) may require longer stays in hospital, develop complications such as intestinal failure, and require more surgery.
Exomphalos
The mortality rates of exomphalos without chromosomal abnormalities or malformations are lower than if they are present.
