BIOMED
Pathophysiology
Everything be alphabetical here (except for Homeostasis at the bottom) 😘
(& Mental Health, Lmao)
There are a lot of neonatal conditions covered, seen in high level NICU/NCCU Units.
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Table of Contents:
1 | Ageing
2 | Canc...
An omphalocele (also known as an exomphalos) is a rare birth defect that occurs within the umbilicus, where there is a herniation of eviscerated abdominal contents covered by a protective membrane, which sets it apart from the similar abdominal wall defect, gastroschisis (see chap for more info).
Normal Embryological Development In utero, a fetus' gut develops around week 3-4, which is before most women even know they are pregnant. During this time, the primitive gut is initially flat and has 3 layers, which will eventually form a tube. Around week 6 of gestation, this tube herniates out through the umbilical membrane. However at 10 weeks, this herniation spontaneously reduces and the herniated bowel comes back inside.
Pathophysiology When there is a failure in this 10-12 week period of the herniated bowel to go back inside, this is when the fetus is said to have an omphalocele. Thus, this defect can bee seen very early on in prenatal ultrasounds. From this point forth, there will be further assessment and fetal consultants and neonatologists becoming involved for education and planning.
Defects are classified (conveniently) into two baskets:
☞ a defect less than 5cm is said to be small, and
☞ a defect greater than 5cm, is said to be giant. These usually involve the liver herniating outside also.
Interestingly though, in the instance of omphaloceles, bigger, really is better. Giant omphaloceles have been found to be less likely to be associated with other congenital anomalies, compared to small omphaloceles.
Because the intestines tend to be protected, babies with omphaloceles do not tend to sustain damage or have long-term issues with their intestinal function, as long as there is not rupture of membranes.
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Associated Complications Omphaloceles are very highly associated with other congenital anomalies, with up to 50% of omphaloceles presenting with some other anomaly present. This is why it is important for fetal and neonatology to become involved early for counselling.
Trisomies 13, 18 and 21 have also been heavily associated with omphaloceles.
Birth Planning There is no evidence to show that it is better to deliver in one way or another, and is up for conversation with families and medical teams.
Surgical Correction Small defects are likely to have surgery done soon after birth, where a surgeon will return the bowl into the abdomen and close the opening.
However if the omphalocele is giant, this area will not have developed fully, and will not be able to fit the herniated contents. This is where the repair will need to be done in stages to slowly stretch and grow the belly enough to house the herniation.
Risk Factors ☞ More common in males and multiple births ☞ Maternal advanced age ☞ Karyotype abnormalies ☞ Congential heart disease
And concerning the fetus, there is a lot that could be going on, and thus a full evaluation of the fetus/neonate should be conducted to see what else could be going on.
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