Omphalocele

Article Author:
Tarik Zahouani
Article Editor:
Magda Mendez
Updated:
3/2/2019 2:48:41 PM
PubMed Link:
Omphalocele

Introduction

Omphalocele is a rare congenital abdominal wall defect with a reported prevalence of 3.38 per 10,000 pregnancies.[1] It is a protrusion of the abdominal contents covered with peritoneum through the base of the umbilical cord. Omphalocele can be isolated but is more frequently associated with other congenital anomalies and syndromes such as Beckwith-Wiedemann syndrome and trisomies 13, 18, and 21. The survival rate is close to 80%, and it is directly related to the severity of the associated anomalies as infants with isolated omphalocele have a higher survival rate (90%).[2]

Etiology

Omphalocele can be associated with several syndromes; the most common is Beckwith-Wiedemann syndrome. Beckwith-Wiedemann syndrome is an overgrowth syndrome characterized by macrosomia, enlarged tongue, neonatal hypoglycemia, ear creases, and pits, hemihypertrophy, visceromegaly, umbilical hernia, embryonal tumors, omphalocele, nephrocalcinosis, medullary sponge kidney disease, cardiomegaly, and nephromegaly. Traditionally, the macrosomia, macroglossia, and hypoglycemia are noted in the neonatal period. Hemihyperplasia is noted in segmental regions of the body or specific organs.[3] Developmental and cognitive outcomes are typically normal. Patients with Beckwith-Wiedemann syndrome have an increased risk of cancer during the first eight years of life with embryonal tumors such as neuroblastoma, hepatoblastoma and Wilms tumor. These embryonal tumors have a higher cure rate when diagnosed early, making screening paramount for prevention. Screening for hepatoblastoma is performed by measuring serum alpha fetoprotein every 3 months until 4 years of age and screening for Wilms tumor is done every 3 months through 8 years of age with a complete abdominal ultrasonography.[4]

Other syndromes associated with omphalocele include the following:

  • Trisomy 13 (Patau syndrome): Small eyes, cleft lip and palate, microcephaly, cryptorchidism, polydactyly, hypertelorism, micrognathia, cutis aplasia and external ears anomalies.[5]
  • Trisomy 18 (Edwards syndrome): Dolichocephaly, external ear anomalies, micrognathia, short palpebral fissures, small face, clenched fist with overriding fingers, hypotonia and rocker bottom feet.[6]
  • Trisomy 21 (Down syndrome): Hypotonia, upslanting palpebral fissures, brachycephaly, low set ears, single palmar crease, flat nasal bridge, brushfield spots around the iris, in-curved fifth digits and a gap between the first and second toes.[7]
  • Pentalogy of Cantrell: Ectopia cordis, midline supraumbilical abdominal defect, sternal cleft and intracardiac defect.[7] 
  • Shprintzen-Goldberg syndrome: Craniosynostosis, dolichocephaly, hypertelorism, exophthalmos, strabismus, elongated fingers and limbs, umbilical and abdominal hernias.[8]
  • Charge syndrome: Coloboma, heart defect, choanal atresia, growth or developmental retardation, genital abnormality, and ear anomalies.[7]
  • Cloacal exstrophy (OEIS) syndrome: exstrophy of the bladder, imperforate anus, spinal defects.[9]
  • Carpenter syndrome: Kleeblattschadel skull deformity (trilobed cloverleaf skull) from pancraniosynostosis, syndactyly in the hands and feet, and mental retardation.[7]
  • Marshall-Smith syndrome: Prominent forehead, shallow orbits, blue sclerae, depressed nasal bridge, micrognathia, accelerated skeletal maturation, respiratory difficulties, mental retardation.[7]
  • Meckel-Gruber syndrome: Occipital encephalocele, cleft lip and palate, microcephaly, microphthalmia, abnormal genitalia, polycystic kidneys, and polydactyly.[7]

Epidemiology

The prevalence of omphalocele in the United States is 1.86 per live births.[10] This prevalence increased by 11% between 1999-2001 and 2005-2007. Omphalocele appears to develop more frequently in women of extreme reproductive age (less than 20 and more than 40 years of age). Omphalocele occurs more commonly in black compared to white persons. Multiple births and male sex also have been associated with omphalocele. 

Pathophysiology

Disturbance of organogenesis during the embryonic period results in omphalocele. Around the sixth week of development, the abdominal contents become too large to be contained in the abdominal cavity and protrude at the base of the umbilical cord. This event is known as physiologic midgut herniation and is easily identified in prenatal ultrasound between the 9 and 11 weeks of gestation. The liver is never present in the physiologic midgut herniation. By 12 weeks of gestation, the hernia reduces, and when it persists, it is no longer physiological. Omphalocele occurs when the gut contents fail to rotate and return to the abdominal cavity. It can occasionally contain the liver in the presence of a large abdominal wall defect.

History and Physical

The diagnosis of omphalocele postnatally is evident on physical examination upon the identification of an anterior midline abdominal mass at the site of the umbilical cord insertion covered by a membrane. The omphalocele can be small with only a few loops of intestines protruding through the defect, large containing several abdominal organs or giant when the defect is greater than or equal to 5 centimeters with the liver partly protruding.

Evaluation

Prenatal diagnosis is based on ultrasound that can detect almost all omphaloceles by the end of the first trimester and elevated maternal serum alpha-fetoprotein concentration.

Treatment / Management

The management of neonate born with omphalocele consists of the initial steps of airway stabilization, sterile wrapping of the bowel to preserve heat to reduce insensible fluid loss, insertion of an orogastric tube for bowel decompression, and the establishment of peripheral intravenous access. In case of vascular compromise suggested by tachycardia, low blood pressure or a dusky bowel appearance, the patient should position left side down right side up.

Providers have to avoid placing dressings that are excessively wet or circumferential as they may macerate the omphalocele and compromise blood flow. 

After the initial steps, the subsequent management involves administration of intravenous fluids and broad-spectrum antibiotics.

If a patient has a small omphalocele surgical repair is an option within the first 72 hours of life via primary closure of the skin and fascia. Patients with other defects benefit from delayed closure after a silo is put in place in the first 24 hours of life. The silo is then progressively reduced over 3 to 7 days before the final closure of the defect. [1]

Differential Diagnosis

Gastroschisis is the main differential diagnosis of omphalocele. In gastroschisis, the intestinal protrusion is usually to the right of the midline, and there is no involvement of the umbilical cord. The membranous sac is a major distinguishing feature of the two conditions as gastroschisis is characterized by free-floating bowel loops, but in case of a giant omphalocele, the membrane can occasionally rupture in-utero. 

Other differential diagnoses include hernias of the umbilical cord with covered abdominal wall defects less than 2 cm, body stalk anomaly characterized by an umbilical cord absent or severely shortened associated with scoliosis.

Prognosis

The prognosis largely depends on the size of the defect and associated congenital anomalies and syndromes. As such, large omphalocele with associated abnormalities have a higher mortality rate. Also, neonates with liver protrusion through the defect appear to have a poorer prognosis. The overall survival rate is close to 80% which reflects the efficacy of prenatal diagnosis and the decision taken by many families to terminate pregnancies with severe anomalies. [11]

Complications

Omphalocele complications can be categorized according to their time of occurrence. Prenatally and during delivery, the omphalocele may rupture, and in case of a giant omphalocele, the liver can be injured. Postnatally and after surgical repair, the complications consist of feeding difficulties, failure to thrive, inguinal hernias, gastroesophageal reflux, and occasionally esophagitis.

Enhancing Healthcare Team Outcomes

The management of omphalocele involves a multidisciplinary team including neonatologists, pediatric surgeons, obstetricians, nurses, pharmacists, and nutritionists. A clear closed-loop communication between the team members is essential to provide optimal care to the patient and assure the best outcome. [12] The majority of these infants require prolonged care in the hospital and are only discharged after the wound has completely healed.


References

[1] Roux N,Jakubowicz D,Salomon L,Grangé G,Giuseppi A,Rousseau V,Khen-Dunlop N,Beaudoin S, Early surgical management for giant omphalocele: Results and prognostic factors. Journal of pediatric surgery. 2018 May 23     [PubMed PMID: 29803304]
[2] Hijkoop A,Peters NCJ,Lechner RL,van Bever Y,van Gils-Frijters APJM,Tibboel D,Wijnen RMH,Cohen-Overbeek TE,IJsselstijn H, Omphalocele: from diagnosis to growth and development at 2 years of age. Archives of disease in childhood. Fetal and neonatal edition. 2018 Mar 21     [PubMed PMID: 29563149]
[3] Barisic I,Boban L,Akhmedzhanova D,Bergman JEH,Cavero-Carbonell C,Grinfelde I,Materna-Kiryluk A,Latos-BieleĊ„ska A,Randrianaivo H,Zymak-Zakutnya N,Sansovic I,Lanzoni M,Morris JK, Beckwith Wiedemann syndrome: A population-based study on prevalence, prenatal diagnosis, associated anomalies and survival in Europe. European journal of medical genetics. 2018 May 16     [PubMed PMID: 29753922]
[4] Brioude F,Hennekam R,Bliek J,Coze C,Eggermann T,Ferrero GB,Kratz C,Bouc YL,Maas SM,Mackay DJG,Maher ER,Mussa A,Netchine I, Revisiting Wilms tumour surveillance in Beckwith-Wiedemann syndrome with IC2 methylation loss, reply. European journal of human genetics : EJHG. 2018 Apr     [PubMed PMID: 29449718]
[5] Hsu HF,Hou JW, Variable expressivity in Patau syndrome is not all related to trisomy 13 mosaicism. American journal of medical genetics. Part A. 2007 Aug 1     [PubMed PMID: 17603803]
[6] Karaman A,Aydin H,Göksu K, Concomitant omphalocele, anencephaly and arthrogryposis associated with trisomy 18. Genetic counseling (Geneva, Switzerland). 2015     [PubMed PMID: 26043511]
[7] Chen CP, Syndromes and disorders associated with omphalocele (III): single gene disorders, neural tube defects, diaphragmatic defects and others. Taiwanese journal of obstetrics & gynecology. 2007 Jun     [PubMed PMID: 17638618]
[8] Zelante L,Germano M,Sacco M,Calvano S, Shprintzen-Goldberg omphalocele syndrome: a new patient with an expanded phenotype. American journal of medical genetics. Part A. 2006 Feb 15     [PubMed PMID: 16411191]
[9] Boujoual M,Madani H,Benhaddou H,Belahcen M, [Conjoined twins at common omphalocele and cloacal exstrophy with sexual ambiguity]. The Pan African medical journal. 2014     [PubMed PMID: 25170387]
[10] Kirby RS, The prevalence of selected major birth defects in the United States. Seminars in perinatology. 2017 Oct     [PubMed PMID: 29037343]
[11] Conner P,Vejde JH,Burgos CM, Accuracy and impact of prenatal diagnosis in infants with omphalocele. Pediatric surgery international. 2018 Jun     [PubMed PMID: 29637257]
[12] Sundgren NC,Kelly FC,Weber EM,Moore ML,Gokulakrishnan G,Hagan JL,Brand MC,Gallegos JO,Levy BE,Fortunov RM, Improving communication between obstetric and neonatology teams for high-risk deliveries: a quality improvement project. BMJ open quality. 2017     [PubMed PMID: 29450281]