Omphalocele

[2][3] Persistence of intestine or the presence of other abdominal viscera (e.g. stomach, liver) in the umbilical cord results in an omphalocele.

Omphalocele occurs in 1 in 4,000 births and is associated with a high rate of mortality (25%) and severe malformations, such as cardiac anomalies (50%), neural tube defect (40%), exstrophy of the bladder and Beckwith–Wiedemann syndrome.

In severe cases surgical treatment is made more difficult because the infant's abdomen is abnormally small, having had no need to expand to accommodate the developing organs.

During management exomphalos can act as a metabolic drain affecting nitrogen balance which can lead to failure to thrive, as well as hypothermia.

[7] Intestinal dysfunction for a few weeks after the surgery is common, therefore parenteral feeding is continued post-surgery, however prolonged use of this may lead to hepatomegaly and cholestasis.

The gut rotates as it re-enters the abdominal cavity which allows for the small intestine and colon to migrate to their correct anatomical position by the end of the 10th week of development.

This process fails to occur normally in cases of exomphalos, resulting in abdominal contents protruding from the umbilical ring.

[7][15][16] Gut contents fail to return to the abdomen due to a fault in myogenesis (muscle formation and migration during embryogenesis).

When FBGF runs out myoblasts stop migrating, cease division and differentiate into myotubules that form muscle fibers.

Mutations in homeobox genes such as Alx4, that direct the formation of body structures during early embryonic development cause exomphalos in mice.

Alcohol use during the first trimester, heavy smoking, use of certain medications like the selective serotonin-reuptake inhibitors and methimazole (anti-thyroid drug) during pregnancy, maternal febrile illness, IVF, parental consanguinity and obesity elevate the risk of a woman giving birth to a baby with exomphalos.

Other related syndromes are Shprintzen Goldberg, pentalogy of Cantrell, Beckwith–Wiedemann and OEIS complex (omphalocele, exstrophy of the cloaca, imperforate anus, spinal defects).

Due to intestinal malrotation 4.4% of children with omphalocele will experience a midgut volvulus in the days, months, or years after surgery.

Parents of children with omphalocele should seek immediate medical attention if their child displays signs and symptoms of an intestinal obstruction at any point in their childhood to avoid the possibility of bowel necrosis or death.

In this case vaginal delivery may result in dystocia (inability of the baby to exit the pelvis during birth) and liver damage.

[6] Immediately after birth a nasogastric tube is required to decompress the intestines and an endotracheal intubation is needed to support respiration.

The exomphalos sac is kept warm and covered with a moist saline gauze and plastic transparent bowel bag to prevent fluid loss.

Closure may require a patch that can be rigid or non-rigid and made of natural biomaterials such as a bovine pericardium or artificial materials.

[22][8][7] The staged surgery is required, as rushed reduction of the exomphalos compromises venous return and ventilation, as it raises intra-abdominal pressure.

This is used for infants with large omphaloceles that have been born prematurely with respiratory insufficiency and associated chromosomal defects, as they would not be able to tolerate surgery.

The ointment causes the sac to granulate and epithelialize, which leaves a residual large ventral hernia, which can be repaired later with surgery when the baby is more stable.

Omphalocele awareness ribbon
Diagram showing the process by which the intestine rotates and herniates during normal development. From panel A to B (left-sided views), the midgut loop rotates 90° in a counterclockwise direction, so that its position changes from midsagittal (A) to transverse (B1). The small intestine forms loops (B2) and slides back into the abdomen (B3) during resolution of the hernia. Meanwhile, the cecum moves from the left to the right side, which represents the additional 180° counterclockwise rotation of the intestine (C, central view). [ 11 ]