Omphalocele: Symptoms, Types, Causes and Treatment

Omphalocele is a rare but serious congenital condition where an infant's abdominal organs develop outside the body, contained within a thin, transparent sac at the base of the umbilical cord. Its complexity and potential associations with other anomalies make early diagnosis and a multidisciplinary approach crucial. In this article, we'll explore the key symptoms, classification types, underlying causes, and the latest approaches to treatment, synthesizing up-to-date research and clinical findings.

Symptoms of Omphalocele

Recognizing the symptoms of omphalocele is essential for timely diagnosis and effective management. While the primary feature is usually clear at birth, associated symptoms can vary and may impact immediate care and long-term outcomes.

Symptom	Description	Associated Anomalies	Source(s)
Visible sac	Abdominal organs protruding in a membrane sac	May involve liver, intestines	3 4 6
Size variation	Defect size ranges from small to giant	Larger defects: higher risks	1 3 7
Cardiac issues	Heart anomalies, especially in large defects	Most common with giant type	1 3 9
GI anomalies	Intestinal atresia, Meckel’s diverticulum	More common in small defects	1 4 7
Respiratory issues	Pulmonary hypoplasia, distress	Especially with large defects	3 9

Table 1: Key Symptoms

Primary Physical Signs

The hallmark symptom of omphalocele is a soft, translucent sac protruding from the abdominal wall at the base of the umbilical cord. This sac can contain various abdominal organs, most often the intestines, but sometimes also the liver and stomach. The sac is typically covered by a thin layer of peritoneum and amnion, which helps distinguish omphalocele from other abdominal wall defects like gastroschisis, where the organs are not covered by a membrane 3 4.

Associated Anomalies

Omphalocele is frequently linked to other congenital anomalies:

• Cardiac anomalies: Particularly common in large or giant omphaloceles. Studies show up to 34.6% of large omphaloceles have associated heart defects 1 3 9.
• Gastrointestinal anomalies: Such as intestinal atresia or Meckel’s diverticulum, more often found in small omphaloceles 1 4 7.
• Pulmonary hypoplasia: Underdeveloped lungs can cause significant respiratory distress, especially with giant omphaloceles 3 9.
• Other findings: Genitourinary and digit abnormalities, sometimes as part of genetic syndromes 5 7.

Clinical Presentation at Birth

• The condition is usually obvious at delivery due to the visible sac.
• Infants may show signs of breathing difficulty, especially if the omphalocele is large and compresses the lungs or if other anomalies are present 3 9.
• In some cases, the sac may rupture before or during birth, increasing the risk of infection and requiring urgent intervention 2.

Prenatal Signs

• Omphalocele can often be detected via prenatal ultrasound, which can identify the externalized organs and help plan delivery and care 3 7.
• Associated anomalies may also be detected prenatally, prompting further genetic testing.

Types of Omphalocele

Omphalocele is not a one-size-fits-all diagnosis. The classification into different types helps guide management and anticipate associated risks.

Type	Defect Size/Features	Typical Contents	Source(s)
Small/Minor	<4–5 cm, often just intestines	Intestines	1 4 7
Giant	>4–5 cm, often includes liver	Liver & intestines	3 8 9
Ruptured	Sac is broken, organs exposed	Variable	2

Table 2: Types of Omphalocele

Small (Minor) Omphalocele

• Defined as a defect less than 4–5 cm in diameter.
• Usually contains only intestinal loops.
• More common in males.
• Tends to be associated with gastrointestinal anomalies (like intestinal atresia) and chromosomal abnormalities (such as trisomy 18 and 13) 1 4 7.

Giant Omphalocele

• Defect larger than 4–5 cm.
• Often includes the liver and sometimes other organs.
• Associated with a higher risk of cardiac anomalies and pulmonary hypoplasia due to the displacement of abdominal contents and restricted lung development 1 3 8 9.
• Management is more complex due to the size and frequent presence of additional malformations.

Ruptured Omphalocele

• The sac surrounding the organs is broken, either before or during birth.
• The risk of infection and fluid loss is significantly increased, making this a surgical emergency 2.
• Requires prompt stabilization and surgical intervention.

Syndromic vs. Non-Syndromic

• Syndromic omphalocele: Occurs as part of a genetic syndrome, such as Beckwith-Wiedemann or pentalogy of Cantrell.
• Non-syndromic omphalocele: Occurs in isolation or with non-syndromic anomalies 5 7.

Causes of Omphalocele

Understanding what causes omphalocele is complex, as both genetic and environmental factors may be involved. Ongoing research continues to uncover the mechanisms underlying this congenital condition.

Cause	Mechanism/Description	Notes/Associations	Source(s)
Genetic mutations	Abnormalities in key developmental genes	Six4, Six5, Hh signaling affected	5 6 7
Chromosomal disorders	Trisomy 18, 13, (aneuploidy)	Often with small omphaloceles	7
Syndromic causes	Part of broader genetic syndromes	Beckwith-Wiedemann, others	5 7
Developmental defects	Failure of ventral body wall closure	Disrupted muscle, mesenchyme dev.	6

Table 3: Causes of Omphalocele

Genetic Factors

• Mutations in critical developmental genes, such as Six4, Six5, and those involved in Hedgehog (Hh) signaling, have been implicated in omphalocele formation. Animal models show that deficiencies in these genes can reproduce the human condition, affecting cell proliferation, mesothelial formation, and body wall closure 5 6.
• Abnormal activation or suppression of signaling pathways (e.g., ectopic Hh signaling) can lead to defective ventral body wall development and omphalocele 5.

Chromosomal Abnormalities

• Chromosomal disorders like trisomy 18 and trisomy 13 are commonly associated with omphalocele, particularly the small type. In one series, about 30% of cases had chromosomal abnormalities, with trisomy 18 present in nearly 59% of those cases 7.
• Chromosomal microarray analysis (CMA) and whole exome sequencing (WES) can detect pathogenic variants and provide valuable information for prenatal counseling and management 7.

Syndromic Associations

• Omphalocele can be a feature of broader genetic syndromes, including Beckwith-Wiedemann syndrome and pentalogy of Cantrell. In these cases, omphalocele is one manifestation among several congenital anomalies 5 7.

Developmental Mechanisms

• During embryogenesis, failure of the ventral body wall to close properly results in herniation of abdominal organs.
• Disrupted proliferation and migration of mesenchyme and muscle precursor cells can lead to abnormal positioning and enlargement of the umbilical ring, resulting in omphalocele 6.

Environmental and Unknown Factors

• While most cases are linked to genetic or chromosomal abnormalities, some may involve environmental influences or remain idiopathic.

Treatment of Omphalocele

Treatment strategies are tailored to the omphalocele’s size, associated anomalies, and the patient’s overall stability. Advances in neonatal care and surgical techniques have improved outcomes, but management remains challenging, especially for giant or ruptured omphaloceles.

Approach	Method/Technique	Indication	Source(s)
Primary closure	Immediate surgical repair	Small omphaloceles	9 12
Staged closure	Silo, mesh, or "paint and wait"	Giant/large omphaloceles	8 9 10 12
Nonoperative	Silver sulfadiazine, negative pressure	Giant omphaloceles	8 9 10
Vacuum-assisted	Negative pressure wound therapy (VAC)	Complex/giant cases	10 11
Ruptured management	Resuscitation, antibiotics, urgent surgery	Ruptured omphaloceles	2

Table 4: Key Treatment Strategies

Initial Assessment and Stabilization

• At birth, the focus is on protecting the sac, preventing infection, and maintaining temperature and hydration.
• If the sac ruptures, broad-spectrum antibiotics and urgent surgical intervention are required to minimize morbidity and mortality 2.

Surgical Treatments

Primary Closure

• Best for small omphaloceles where abdominal contents can be safely returned to the cavity without causing excessive pressure or compromising breathing.
• Involves immediate surgical repair soon after birth 9 12.

Staged Closure

• For giant omphaloceles, where the abdominal cavity is too small to accommodate all organs at once:
  • Silo placement: A synthetic or biological silo is placed over the sac, allowing gradual reduction of contents into the abdomen over days to weeks 8 9 12.
  • Mesh repair: Synthetic or biologic meshes may be used if the defect cannot be closed primarily 2 8.
  • "Paint and wait": Nonoperative epithelialization of the sac using topical agents like silver sulfadiazine, followed by delayed surgical repair 8 9.
• Both staged and nonoperative approaches aim to minimize respiratory and circulatory compromise.

Negative Pressure Wound Therapy (VAC)

• An innovative approach for giant or complicated omphaloceles.
• Involves applying a vacuum device to promote wound contraction and granulation, while allowing for feeding and reducing infection risk 10 11.
• VAC therapy can be used as a bridge to definitive closure with skin grafts or mesh 11.

Nonoperative Management

• Especially for giant omphaloceles with high surgical risk, delayed closure is preferred.
• Topical therapies (silver sulfadiazine, negative pressure) are applied to promote safe epithelialization and gradual reduction of the herniated organs 8 9 10.
• Studies show that nonoperative management is associated with lower mortality and a shorter time to full enteral feeding compared to staged surgical closure 8.
• Once the infant's condition stabilizes and the abdominal cavity has grown, delayed surgical repair is performed.

Special Considerations for Ruptured Omphalocele

• Ruptured omphaloceles are emergencies, requiring:
  • Immediate resuscitation (IV fluids, temperature control)
  • Broad-spectrum antibiotics
  • Urgent surgical coverage of the abdominal contents 2

Management of Associated Conditions

• Many infants have associated cardiac or pulmonary anomalies that require concurrent or staged management 3 9.
• Multidisciplinary care, involving neonatology, surgery, genetics, and cardiology, is key to optimizing outcomes.

Long-Term Outcomes

• Prognosis depends on the size of the defect, presence of associated anomalies, and timeliness of intervention.
• Even with advances in care, giant and ruptured omphaloceles are associated with significant morbidity and mortality 2 3 8 9.

Conclusion

Omphalocele is a complex congenital condition that requires early diagnosis, careful assessment of associated anomalies, and individualized treatment. Advances in genetics and surgical techniques continue to improve the outlook for affected infants, but challenges remain, especially for giant and ruptured cases.

Key takeaways:

• Omphalocele is characterized by protrusion of abdominal organs in a membrane sac at the umbilicus.
• Symptoms and associated anomalies vary, with cardiac issues common in large defects and GI anomalies more frequent in small ones 1 3 4 7.
• Types include small, giant, and ruptured omphaloceles, each with distinct management needs 1 3 7.
• Causes are often genetic, including chromosomal abnormalities and developmental gene defects 5 6 7.
• Treatment is guided by defect size and associated anomalies, with primary closure for small defects and staged or nonoperative approaches for giant omphaloceles 8 9 10 12.
• Early detection and multidisciplinary care are crucial for optimizing outcomes.

By understanding the nuances of omphalocele, clinicians and families can better navigate the challenges and opportunities for affected newborns.