Overview
Definition:
Gastroschisis and omphalocele are congenital anterior abdominal wall defects
Gastroschisis is characterized by herniation of abdominal contents through a defect usually to the right of the umbilical cord insertion, with no peritoneal covering
Omphalocele is the herniation of abdominal viscera within a sac of peritoneum and amnion, located at the base of the umbilical cord.
Epidemiology:
Gastroschisis occurs in approximately 1 in 2000 to 3000 live births, with a slight female predominance
It is often isolated
Omphalocele occurs in approximately 1 in 5000 to 10,000 live births and is frequently associated with other chromosomal abnormalities (e.g., trisomy 21, 18, 13) and other congenital anomalies, making it part of a syndrome in about 60-80% of cases.
Clinical Significance:
These conditions represent significant surgical emergencies requiring prompt diagnosis, meticulous stabilization, and timely surgical intervention
Understanding the differences in their embryogenesis, associated anomalies, and management strategies is crucial for optimal patient outcomes and for success in DNB and NEET SS pediatrics examinations.
Clinical Presentation
Symptoms:
Presentation is at birth
Visible abdominal organs protruding from the umbilical area
The defect in gastroschisis is typically small (2-4 cm) and located to the right of the umbilical cord
In omphalocele, the defect is central, and the abdominal contents are covered by a translucent membrane
Signs of bowel obstruction may be present if there is significant bowel injury or volvulus.
Signs:
A neonate with an abdominal wall defect is identified immediately after birth
The protruding organs are not covered by skin or peritoneum in gastroschisis, often appearing edematous and congested
In omphalocele, the sac is intact and may vary in size, containing varying amounts of bowel, liver, and other organs
Vital signs may indicate compromise due to fluid loss, hypothermia, and sepsis.
Diagnostic Criteria:
Diagnosis is typically made antenatally via ultrasound, which is highly accurate for both conditions
Postnatally, the diagnosis is clinical based on the visual inspection of the neonate at birth, revealing the characteristic abdominal wall defect.
Diagnostic Approach
History Taking:
Antenatal ultrasound findings are key
Postnatally, focus on the gestational age, presence of other congenital anomalies, and any signs of distress or compromise
Inquire about maternal health and any complications during pregnancy.
Physical Examination:
Immediate assessment of the neonate
Carefully inspect the size and location of the defect
Assess the viability and integrity of the protruding organs
Evaluate for other congenital anomalies (e.g., limb abnormalities, cardiac defects, facial dysmorphism)
Assess for signs of hypothermia, dehydration, and shock
Gently palpate the abdomen if possible without disrupting the sac or exposed bowel.
Investigations:
Karyotyping and genetic testing are indicated, especially in omphalocele, to rule out associated chromosomal abnormalities
Echocardiography and other organ-specific imaging may be performed to assess for associated anomalies
Baseline laboratory investigations include complete blood count, electrolytes, blood gas analysis, and blood cultures if sepsis is suspected
Plain abdominal X-ray may show bowel dilation and gas pattern.
Differential Diagnosis:
Gastroschisis and omphalocele are distinct diagnoses
Other rare abdominal wall defects like ectopia cordis, pentalogy of Cantrell, or limb-body wall complex should be considered if the defect is extensive or associated with other anomalies
Prune belly syndrome presents with absent abdominal musculature and other genitourinary abnormalities, but not typically herniation of organs outside the abdomen at birth.
Management
Initial Management:
Immediate stabilization is paramount
The defect should be covered with sterile saline-moistened gauze and a non-adherent dressing (e.g., plastic wrap) to prevent heat and fluid loss and contamination
Intravenous fluids should be initiated for hydration and electrolyte correction
A nasogastric tube should be inserted to decompress the stomach and prevent aspiration
Broad-spectrum antibiotics are administered to prevent infection
Maintain normothermia.
Medical Management:
Fluid resuscitation and electrolyte balance are critical
Monitor central venous pressure if available
Nutritional support will be parenteral (TPN) until enteral feeding is tolerated
Vasoactive support may be needed in cases of severe shock.
Surgical Management:
Surgical timing and approach depend on the defect size, the amount of eviscerated organs, and the presence of intact sac (omphalocele)
For gastroschisis, immediate or early surgical closure is often attempted if the bowel is not too edematous and the abdominal cavity is sufficiently large
This may involve primary closure or staged repair using a Silastic silo
For omphalocele, if the sac is intact and the defect is small to moderate, primary closure can be attempted
Larger omphalocele defects or those with significant liver involvement may require a staged approach with a silo
The decision for primary vs
staged closure is crucial for preventing abdominal compartment syndrome.
Supportive Care:
Close monitoring of vital signs, urine output, and abdominal girth is essential
Neonatal intensive care unit (NICU) admission is mandatory
Pain management is important
Enteral feeding is gradually introduced once bowel function returns and is tolerated
Management of potential complications like sepsis, necrotizing enterocolitis (NEC), and malrotation is critical.
Complications
Early Complications:
Bowel obstruction due to adhesions or strictures
Sepsis
Necrotizing enterocolitis (NEC)
Abdominal compartment syndrome
Wound dehiscence
Hypothermia
Dehydration
Malrotation with midgut volvulus.
Late Complications:
Adhesions leading to long-term bowel obstruction
Intestinal dysfunction (short bowel syndrome if significant bowel resection is needed)
Growth and developmental delays
Pulmonary hypoplasia (especially with large omphaloceles or prolonged abdominal compartment syndrome)
Fertility issues.
Prevention Strategies:
Meticulous surgical technique to avoid bowel injury during repair
Prompt recognition and management of abdominal compartment syndrome
Judicious use of antibiotics
Gradual introduction of enteral feeds
Careful monitoring for NEC and malrotation
Aggressive fluid management to maintain perfusion.
Prognosis
Factors Affecting Prognosis:
For gastroschisis, the main determinants of outcome are the degree of bowel injury (edema, necrosis, atresia) and the duration of parenteral nutrition required
For omphalocele, associated anomalies and chromosomal abnormalities significantly impact prognosis
The size of the omphalocele and the extent of liver herniation also play a role.
Outcomes:
With modern surgical management and intensive care, survival rates for gastroschisis are high (90-95%)
Outcomes for omphalocele vary widely depending on associated anomalies
isolated omphaloceles have good prognosis, while those with significant anomalies may have poorer outcomes
Long-term morbidity can include feeding difficulties, growth problems, and recurrent abdominal issues.
Follow Up:
Long-term follow-up is essential, particularly for nutritional status, growth and development, and monitoring for signs of gastrointestinal complications
Referral to developmental pediatricians or surgeons may be necessary
Patients with omphalocele should have ongoing surveillance for associated conditions.
Key Points
Exam Focus:
Differentiate gastroschisis from omphalocele based on defect location, presence of a sac, and association with other anomalies
Understand the immediate management priorities: coverage, fluid resuscitation, decompression, and thermal support
Recognize indications for primary vs
staged surgical repair and the risk of abdominal compartment syndrome.
Clinical Pearls:
Always assume a neonate with an abdominal wall defect requires immediate surgical consultation and NICU care
The presence of a membrane covering the defect strongly suggests omphalocele and warrants thorough assessment for aneuploidies and other anomalies
A gastroschisis defect is typically to the right of the umbilical cord, and the bowel is not covered by a membrane.
Common Mistakes:
Delaying surgical consultation
Inadequate initial stabilization (failure to cover the defect, insufficient fluid resuscitation)
Aggressive attempts at primary closure of large defects leading to abdominal compartment syndrome
Underestimating the risk of associated anomalies in omphalocele
Failing to consider midgut volvulus in a compromised bowel.