Surgery chapters
Exomphalos major and minor, gastroschisis and congenital diaphragmatic hernia
The two main abdominal wall defects of the newborn, exomphalos (covered by a sac, many associated anomalies) and gastroschisis (no sac, right of the cord, usually isolated), and congenital diaphragmatic hernia with its pulmonary hypoplasia.
- Exomphalos is a midline defect at the umbilicus with bowel (and in major cases liver) inside a membranous sac, the cord inserting into the sac; it often has chromosomal, cardiac and syndromic links (e.g. Beckwith–Wiedemann).
- Gastroschisis is a small defect to the right of a normal cord with no sac; exposed bowel is thickened by a fibrinous peel; it is usually isolated, seen in young mothers, and has a good outlook.
- Congenital diaphragmatic hernia is usually left posterolateral (Bochdalek); the newborn has respiratory distress, a scaphoid abdomen and mediastinal shift; outcome depends on pulmonary hypoplasia and pulmonary hypertension.
On this page
Overview
These are major structural anomalies often found on antenatal ultrasound, allowing delivery in a centre with neonatal surgery.
- Exomphalos (omphalocele) and gastroschisis are both defects of the anterior abdominal wall with bowel outside the abdomen, but they differ in cause, covering, associations and outlook.
- Congenital diaphragmatic hernia (CDH) lets abdominal organs into the chest, so the lung on that side (and to a lesser extent the other lung) fails to grow.
Embryology in brief
- In early fetal life the midgut grows too fast for the abdomen and physiologically herniates into the umbilical cord; it returns by about the 10th–12th week and rotates.
- Exomphalos: the gut (and sometimes liver) fails to return, or the lateral body wall folds fail to close, so viscera stay in the base of the cord, covered by amnion and peritoneum (the sac).
- Gastroschisis: a full-thickness defect in the abdominal wall, usually to the right of the cord, probably from a vascular insult in the area of the right umbilical vein; bowel herniates without any covering and floats in amniotic fluid, which inflames it.
- CDH: the diaphragm forms from the septum transversum, pleuroperitoneal membranes, mesentery of the oesophagus and body wall muscle. Failure of the pleuroperitoneal membrane to close the posterolateral channel leaves the Bochdalek defect.
Exomphalos versus gastroschisis
| Feature | Exomphalos (omphalocele) | Gastroschisis |
|---|---|---|
| Site | Midline, at the umbilicus | Right of the umbilical cord (paraumbilical) |
| Covering | Membranous sac (amnion + peritoneum) | No sac |
| Cord | Inserts into the sac | Normal, separate, to the left of the defect |
| Contents | Bowel ± liver (major) | Small and large bowel (rarely liver) |
| Bowel appearance | Normal (protected) | Thickened, matted, oedematous, short, covered with a fibrinous peel |
| Defect size | Small to very large | Usually small |
| Associated anomalies | Common: chromosomal (trisomy 13, 18, 21), cardiac, Beckwith–Wiedemann, pentalogy of Cantrell, bladder exstrophy | Uncommon; intestinal atresia in some, undescended testes |
| Maternal age | Often older | Young mothers (under 20); smoking, recreational drugs |
| Maternal AFP | Raised | Raised (often higher) |
| Prognosis | Depends on associated anomalies | Good survival; slow return of gut function |
"Gastroschisis: Gut Goes out Guarded by nothing, on the riGht." And "Omphalocele: Organs in an Overcoat."
The sac is the key. Ruptured exomphalos can look like gastroschisis, but the defect is at the umbilicus with remnants of the sac and the cord coming from it.
Exomphalos major and minor
| Type | Features |
|---|---|
| Exomphalos minor | Small defect containing only bowel; easy primary closure. Do not confuse with an umbilical cord hernia; never clamp across a swollen cord base (bowel may be inside) |
| Exomphalos major | Large defect, usually containing liver as well as bowel; abdominal cavity is small; often linked with pulmonary hypoplasia; staged or delayed closure |
| Giant exomphalos | Most of the liver outside; very small abdomen |
Beckwith–Wiedemann syndrome
An overgrowth syndrome (imprinting defect at chromosome 11p15):
- Exomphalos
- Macroglossia (large tongue)
- Hemihypertrophy, organomegaly, gigantism
- Neonatal hypoglycaemia (islet cell hyperplasia): check glucose
- Higher risk of Wilms tumour and hepatoblastoma, so regular abdominal ultrasound screening in childhood
Exomphalos = look for other anomalies (heart, chromosomes, Beckwith–Wiedemann); gastroschisis = look at the bowel (atresia, ischaemia).
Management of exomphalos
- Cover the sac with a moist, sterile dressing; keep it intact. NG tube, IV fluids, keep warm.
- Look for other anomalies: echocardiogram, karyotype, glucose.
- Minor: primary surgical closure.
- Major/giant: a sac that is intact allows a non-operative "paint and wait" approach, in which the sac is painted with an antiseptic or other agent so it scabs and epithelialises, leaving a ventral hernia to repair later; or staged closure with a silo.
Management of gastroschisis
Immediate (in the delivery room):
- Cover the bowel with a sterile, transparent plastic bowel bag or cling film to cut heat and fluid loss (avoid wet gauze that cools the baby).
- Lie the baby on the right side (or support the bowel) so the mesentery does not kink and the bowel stays pink.
- NG tube to decompress the stomach; IV fluids (high losses), antibiotics, warmth; check glucose.
- Check bowel colour often (ischaemia from a tight defect).
Surgery:
- Primary reduction and closure if the bowel fits without high pressure, or
- Staged reduction with a preformed silo (a silastic bag over the bowel), reduced gently every 12–24 hours over days, then closure (often sutureless, using the cord).
- Long period of parenteral nutrition while gut motility recovers.
Complications: dysmotility (slow feeding), intestinal atresia, NEC, short bowel, sepsis, abdominal compartment syndrome if closed too tight.
Gastroschisis has a good prognosis (high survival) because other anomalies are rare; the main delay is gut dysmotility from the peel.
Congenital diaphragmatic hernia (CDH)
Types
| Type | Site | Notes |
|---|---|---|
| Bochdalek (commonest) | Posterolateral, usually left (most cases) | Presents at birth with respiratory distress; posterior defect through the lumbocostal triangle |
| Morgagni | Anterior, retrosternal (usually right) | Rare; often presents later or by chance |
| Eventration | Diaphragm intact but thin, with no muscle | Raised hemidiaphragm; not a true hernia |
The left side is affected far more often (Basis of Paediatrics: about 80%); bilateral cases are rare. The liver protects the right side. Incidence is about 1 in 3000 births.
Pathophysiology
- Abdominal organs in the chest compress the developing lung → pulmonary hypoplasia (fewer airway branches and fewer, thick-walled pulmonary arteries). Both lungs are small, the same-side lung worst.
- This causes persistent pulmonary hypertension of the newborn with right-to-left shunting and hypoxia.
- Severity of pulmonary hypoplasia and hypertension decides survival.
Clinical features
- Antenatal ultrasound: stomach or bowel in the chest, mediastinal shift, polyhydramnios.
- At birth: respiratory distress and cyanosis, worse with crying or feeding.
- Scaphoid (sunken) abdomen because the organs are in the chest.
- Barrel chest; absent breath sounds on the affected side (bowel sounds may be heard); apex beat and heart sounds displaced to the right (with a left CDH).
- Small defects may present later with respiratory or bowel symptoms, or obstruction.
Investigations
- Chest X-ray: bowel loops (gas-filled cysts) in the left chest, mediastinal shift to the right, little gas in the abdomen, the NG tube tip in the chest (stomach herniated).
- Echocardiogram (heart defects, pulmonary pressures); look for other anomalies.
On X-ray, a left CDH can look like congenital cystic adenomatoid malformation (CPAM/CCAM) or staphylococcal pneumatoceles. The NG tube curling into the chest and a scaphoid abdomen point to CDH.
Management
Resuscitation (the key steps):
- Avoid bag-and-mask ventilation, which inflates the stomach and bowel in the chest and worsens compression.
- Immediate endotracheal intubation and gentle ventilation (low pressures to avoid pneumothorax in the hypoplastic lung).
- Large-bore NG tube on suction to decompress the gut.
- Treat pulmonary hypertension (oxygen, nitric oxide, inotropes); ECMO in selected centres.
- Nurse head up, keep warm, IV fluids.
Surgery:
- Not an emergency: repair after the baby is stabilised (often days).
- Usually via an abdominal (subcostal) incision (or thoracoscopically): reduce viscera, close the defect primarily or with a patch for large defects.
- Malrotation is common because the gut was in the chest.
Prognosis
- Despite modern care, up to about 30% die, mainly from pulmonary hypoplasia and pulmonary hypertension.
- Poor signs: severe distress within the first hours (before 24 hours), liver in the chest, associated major anomalies (heart, chromosomes), need for ECMO.
- Survivors may have reflux, chronic lung disease and recurrence.
CDH death is from the lungs, not the hernia. Surgery is delayed until the baby's breathing and circulation are stable.
Expect: distinguishing exomphalos from gastroschisis (sac, site, cord, associations, maternal age, prognosis), exomphalos major versus minor (liver), Beckwith–Wiedemann features (exomphalos, macroglossia, hypoglycaemia, Wilms risk), first aid for gastroschisis (cling film/bowel bag, NG tube, fluids, warmth) and silo; CDH type and side (Bochdalek, left posterolateral), embryology (pleuroperitoneal membrane), clinical signs (scaphoid abdomen, shifted heart), X-ray (bowel in chest, NG tube in chest), avoid bag-mask ventilation, intubate, delayed repair, and pulmonary hypoplasia as the cause of death.
Quick revision
- Exomphalos: midline, sac, cord on sac, many associations, older mothers.
- Major exomphalos contains liver; minor only bowel.
- Gastroschisis: right of cord, no sac, peel, young mothers, isolated, good outlook.
- Gastroschisis first aid: cover with plastic, right side down, NG tube, warm fluids.
- Silo for staged reduction; TPN while the gut recovers.
- Beckwith–Wiedemann: exomphalos, big tongue, hypoglycaemia, Wilms risk.
- CDH: Bochdalek left posterolateral; scaphoid abdomen; heart pushed right.
- No bag-mask; intubate; NG suction; repair once stable.
- Death from pulmonary hypoplasia and pulmonary hypertension (up to about 30%).
Written by The House Job from standard references (Bailey & Love; Basis of Paediatrics).
FAQ
What is the single best way to tell exomphalos from gastroschisis?
Exomphalos has a membranous sac with the cord inserted into it at the umbilicus; gastroschisis has no sac and lies to the right of a normal cord.
Which abdominal wall defect has more associated anomalies?
Exomphalos, which is linked with chromosomal disorders, heart defects and Beckwith–Wiedemann syndrome; gastroschisis is usually isolated apart from intestinal atresia.
Why is bag-and-mask ventilation avoided in congenital diaphragmatic hernia?
It blows air into the stomach and bowel lying in the chest, which compresses the lungs further; the baby should be intubated and the stomach decompressed.
Is CDH repaired immediately after birth?
No. The baby is first stabilised on the ventilator and the pulmonary hypertension treated; repair is done electively once stable.