FCPS Paediatrics TOACS · Interactive Station

✅ Candidate's structured answer:
• Findings: Right-sided, full-thickness abdominal wall defect. Umbilical cord is normally inserted (not into the defect). Eviscerated bowel loops (small intestine) are edematous, matted, and thickened, with a fibrinous exudate. No covering membrane.
• Diagnosis: Gastroschisis.
• Differentiation from omphalocele:
- Gastroschisis: No sac, normal cord insertion, defect usually right-sided, bowel is exposed, associated with intestinal atresia/stenosis (10-15%), rarely associated with other major anomalies.
- Omphalocele: Sac covers the defect, cord inserts into the sac, midline defect, can contain liver, high rate of associated anomalies (cardiac, chromosomal, Beckwith-Wiedemann).

✅ Candidate's answer:
• Exact embryology is unclear. Leading theories:
1️⃣ Disruption of the right umbilical vein → compromised blood flow to the developing abdominal wall → ischemic necrosis → full-thickness defect.
2️⃣ Abnormal involution of the right omphalomesenteric artery.
3️⃣ Failure of mesodermal folding during 4th-5th week of gestation leading to a body wall defect.
• Unlike omphalocele (failure of gut herniation to return), gastroschisis results from a defect in the lateral abdominal wall.
• The bowel herniates directly into the amniotic fluid, causing chemical peritonitis → thickened, edematous, matted loops with a peel (fibrinous exudate).
• The defect is almost always right-sided (except rare left-sided).

✅ Candidate's answer:
• Gastroschisis is usually an isolated anomaly (fewer associated anomalies than omphalocele).
• However, associated anomalies occur in ~10-15%:
- Gastrointestinal atresia/stenosis (most common – small bowel atresia, 10-15%) – due to intrauterine vascular compromise.
- Malrotation, gastric perforation, necrotizing enterocolitis.
- Undescended testes (in males).
- Prematurity and intrauterine growth restriction (IUGR) are very common.
- Cardiac anomalies are rare (unlike omphalocele).
• Chromosomal anomalies are extremely rare in gastroschisis (unlike omphalocele with trisomy 13,18,21).
• Therefore, routine karyotype is not indicated unless dysmorphic features are present.

✅ Candidate's structured answer:
1️⃣ Protect the exposed bowel: Cover the eviscerated intestines with sterile, moist, non-adherent dressing (e.g., saline-soaked gauze) and then a plastic bowel bag or cling wrap to minimize heat and fluid loss. Do not use povidone-iodine or alcohol.
2️⃣ Place infant in a sterile plastic bag (from the neck down) to maintain warmth. Radiant warmer on.
3️⃣ Orogastric (OG) tube placement to decompress the stomach and prevent aspiration, continuous low suction.
4️⃣ Intravenous access (umbilical venous catheter or peripheral line) for fluids. Begin IV fluids (normal saline bolus if hypotensive).
5️⃣ Broad-spectrum IV antibiotics (ampicillin + gentamicin + metronidazole) due to risk of peritonitis/sepsis.
6️⃣ Position infant in right lateral or semi-prone to avoid pressure on the mesentery (avoid supine).
7️⃣ Monitor vital signs, temperature, glucose, electrolytes.
8️⃣ Urgent pediatric surgery consultation for definitive closure (primary vs staged).

✅ Candidate's answer:
• Bowel changes: Prolonged exposure to amniotic fluid causes chemical irritation and inflammation → serositis → edema, thickening, fibrin deposition ("peel"), and loops become matted together.
• Precautions:
- Do not manipulate or attempt to reduce bowel at bedside – can cause mesenteric torsion or injury.
- Do not use gauze directly on bowel (can adhere). Use saline-soaked non-adherent dressing, then plastic wrap.
- Elevate the bowel above the abdominal wall using a bowel bag to prevent twisting of the mesentery.
- Monitor for signs of vascular compromise – dusky bowel, absent Doppler signals, worsening acidosis.
- If bowel is compromised, emergent operative intervention needed.

✅ Candidate's answer:
• Hypothermia risk: Large surface area of eviscerated bowel leads to massive evaporative heat loss. Prevention: place infant in sterile plastic bag (body + bowel) under radiant warmer, warm humidified gases if intubated, warm IV fluids.
• Fluid loss: Eviscerated bowel loses water and protein through the inflamed surface (third spacing). Infants have high insensible losses and often require large volumes of IV fluids (1.5-2 times maintenance). Monitor urine output, electrolytes, and blood pressure. Normal saline or lactated Ringer’s boluses as needed. Begin maintenance fluids with higher glucose (D10 1/2 NS). Hypovolemia can lead to renal failure, acidosis, and bowel ischemia.
• Monitor for abdominal compartment syndrome after closure.

✅ Candidate's answer:
• Primary closure (single operation): The bowel is reduced into the abdominal cavity, and the abdominal wall is closed primarily (with or without fascial relaxation incisions).
- Indications: Minimal bowel edema, small defect, adequate abdominal domain.
- Advantages: Single surgery, shorter hospital stay.
- Risks: Abdominal compartment syndrome, respiratory compromise, bowel ischemia (if reduced under tension).
• Staged closure (silo placement): A spring-loaded or preformed silo (plastic bag) is sutured to the fascial edges; bowel is gradually reduced over 3-7 days by gravity and gentle compression, followed by delayed primary closure.
- Indications: Large defect, significant bowel edema, viscero-abdominal disproportion.
- Advantages: Reduces intra-abdominal pressure, prevents compartment syndrome.
- Disadvantages: Longer duration of anesthesia exposure (multiple reductions), longer hospital stay, risk of silo dislodgement, sepsis.
• Most centers use staged closure with preformed silo as the standard of care.

✅ Candidate's answer:
• Not an absolute emergency unless bowel is compromised (vascular injury, perforation).
• Stabilization takes priority: correct hypothermia, acidosis, hypotension, electrolyte imbalances.
• Surgery is typically performed within 24-48 hours after birth once the infant is hemodynamically stable.
• Delayed closure (after 48 hours) is sometimes performed if bowel edema is severe (allows time for edema to decrease with bowel bag and suspension).
• Emergency surgery indicated for: Bowel perforation, necrotic bowel, abdominal compartment syndrome, or inability to maintain stability due to massive fluid sequestration.

✅ Candidate's answer:
• Early complications:
- Abdominal compartment syndrome (increased intra-abdominal pressure → renal failure, respiratory compromise, bowel ischemia).
- Respiratory failure (restrictive lung disease due to tight closure) – may require prolonged ventilation.
- Wound infection, dehiscence, fascial breakdown.
- Sepsis (central line-associated, peritonitis).
- Necrotizing enterocolitis (NEC).
- Postoperative ileus.
• Late complications:
- Short bowel syndrome (SBS) – due to intestinal atresia, necrosis, or massive resection.
- Intestinal failure-associated liver disease (IFALD) from prolonged parenteral nutrition.
- Feeding intolerance, gastroesophageal reflux, failure to thrive.
- Adhesive small bowel obstruction.
- Recurrent line sepsis.
- Neurodevelopmental delay (if prolonged hospitalization, sepsis, or SBS).

✅ Candidate's answer:
• Multidisciplinary intestinal rehabilitation program.
• Parenteral nutrition (PN): Central venous access; monitor for cholestasis, line sepsis, metabolic bone disease.
• Intestinal adaptation: Early enteral feeds (trophic, then slow advancement) with hydrolyzed formula or breast milk. Use of teduglutide (GLP-2 analogue) to enhance adaptation.
• Prevention of bacterial overgrowth: Cyclical antibiotics (metronidazole, gentamicin).
• Surgical options: Serial transverse enteroplasty (STEP), intestinal lengthening, or intestinal transplantation for refractory failure.
• Long-term nutrition and growth monitoring.

✅ Candidate's answer:
• Ultrasound findings (second trimester): Loops of bowel floating freely in amniotic fluid (no covering membrane), normal cord insertion, bowel dilation may indicate atresia. Polyhydramnios (if obstruction).
• Fetal MRI adjunct.
• Serial ultrasound monitoring: Bowel dilation (risk of atresia), polyhydramnios (risk of preterm labor), fetal growth restriction.
• Counseling parents:
- Explain the condition, good survival (>90% in developed countries).
- Plan delivery at a tertiary center with NICU and pediatric surgery.
- Mode of delivery: vaginal delivery is acceptable; no proven benefit of elective C-section (unless obstetric indications).
- Discuss postnatal management (bowel protection, surgery, complications, long-term nutrition).
- Recurrence risk is very low (<1%).

✅ Candidate's answer:
• Excellent survival (>90%) with modern neonatal and surgical care.
• Most children have normal gastrointestinal function and quality of life.
• However, morbidity is significant:
- Up to 30% have feeding difficulties, gastroesophageal reflux, food aversion.
- Risk of adhesive small bowel obstruction (10-15%) requiring further surgery.
- Short bowel syndrome in 5-10% (if intestinal atresia or massive resection).
- Neurodevelopmental impairment (mild) may occur due to prematurity, sepsis, prolonged hospitalization, but most have normal cognition.
- Long-term follow-up: Multidisciplinary (surgery, gastroenterology, nutrition, developmental pediatrics).

✅ Candidate's answer:
• Recurrence risk is very low (<1-2%). Gastroschisis is generally sporadic.
• No known teratogens definitively cause gastroschisis; however, young maternal age (especially <20 years) is strongly associated.
• No proven prevention strategies.
• Prenatal screening in future pregnancies: detailed fetal anatomy ultrasound at 18-22 weeks.
• Reassure parents: The chance of having another child with gastroschisis is extremely low.

✅ Candidate's structured answer:
• “Your baby has a condition called gastroschisis – a hole in the abdominal wall next to the belly button. The intestines are on the outside of the belly, but they are not damaged.”
• “We will immediately cover the intestines with a sterile plastic bag to keep them warm and moist, and start IV fluids and antibiotics.”
• “The baby will be transferred to a children’s hospital where a pediatric surgeon will place the intestines back into the abdomen. This may be done in one surgery or gradually over several days using a plastic silo (a temporary pouch).”
• “Most babies do very well. Survival is >90% with modern care. The main concerns are feeding difficulties and prolonged hospital stay (often 4-8 weeks).”
• “Some babies develop intestinal narrowing (atresia) or require long-term IV nutrition if a large portion of bowel is damaged, but most eventually eat normally.”
• “You are not alone. We have a team of surgeons, neonatologists, nutritionists, and support staff who will care for your baby every step of the way.”
• “You can visit, hold your baby’s hand, and once stable, you will be able to provide breast milk (expressed) which helps the intestines heal.”
• “The chance of this happening again in a future pregnancy is less than 1%.”