Gastroschisis is a congenital abdominal wall defect typically occurring to the right of the umbilicus, presenting with evisceration of the bowel and/or other abdominal organs, without a protective covering sac.
Description
Gastroschisis is a congenital defect of the anterior abdominal wall, usually situated to the right of the umbilicus. It results in herniation of the bowel, and occasionally other abdominal organs, into the amniotic cavity without a covering sac. It is one of the most common types of congenital abdominal wall defects in neonates.
Pathogenesis
The exact cause of gastroschisis is unknown. One theory suggests that it results from a disruption of the omphalomesenteric artery during embryological development, leading to a mesodermal defect that ultimately results in an abdominal wall defect through which the intestine herniates.
Subtypes
There are no recognised subtypes of gastroschisis.
Epidemiology, Risk Factors & Associations
- Incidence: Approximately 1 in 2000-5000 live births.
- More common in young, first-time mothers.
- Maternal drug and alcohol use are risk factors.
Clinical Features
- The key clinical feature is the presence of herniated bowel, typically to the right of the umbilicus, without a covering sac, immediately apparent at birth.
- The extruded bowel may be inflamed and matted due to exposure to amniotic fluid.
Complications
- Inflammation and damage to the exposed bowel can lead to bowel dysfunction and malabsorption.
- There is a risk of infection due to exposure of the bowel.
- Dehydration and electrolyte imbalances may occur as a result of fluid loss from the exposed bowel.
Pathological Features
Histopathology
- Macroscopic: Bowel and possibly other abdominal organs located outside the abdominal cavity, with no protective sac.
- Microscopic: Not applicable as gastroschisis is a gross anatomical defect.
Serology
- Not relevant
Biochemistry
- Not specifically relevant
Radiological Features
General Features
- Prenatal ultrasound typically shows bowel loops floating freely in the amniotic fluid.
XR
- Postnatal radiographs may show air-filled bowel loops located outside the abdominal cavity.
US
- B-mode: Prenatal scans reveal free-floating bowel loops in the amniotic fluid with an abdominal wall defect, typically to the right of the umbilicus.
- Colour Doppler: Not typically applicable in this context.
Diagnosis
- Diagnosis is often made prenatally via ultrasound.
- Postnatal diagnosis is clinical, based on the characteristic appearance of eviscerated bowel at birth.
Differential Diagnosis
- Omphalocele: Another type of abdominal wall defect, but with a covering sac. The location is midline, involving the umbilicus, unlike gastroschisis which is typically right-sided.
- Physiological midgut herniation: Normal in early pregnancy and resolves by 12 weeks.
Prognosis
- Prognosis is generally good with surgical repair, but depends on the degree of bowel damage and presence of any associated anomalies.
Management
- Prompt neonatal surgical consultation is necessary, and supportive care is crucial to maintain hydration and prevent infection and further bowel damage.
- Surgical repair of the defect is the definitive treatment, typically performed shortly after birth.