Gastroschisis

10 Interesting Facts of Gastroschisis

1. Gastroschisis is a full-thickness abdominal wall defect usually located to the right of the umbilicus beside normally inserted umbilical vessels 
   • Neonates are born with variable amounts of intestine and occasionally other abdominal organs herniated through the abdominal wall defect
   • No membrane or sac covers the herniated abdominal contents
2. Gastroschisis is often an isolated abnormality, although a small percentage are complicated by additional gastrointestinal abnormalities (eg, atresia, necrosis)
3. Most abdominal wall defects are diagnosed in the prenatal period through routine screening studies; defects are detectable with prenatal ultrasonography and suggested by nonspecific elevation in maternal α-fetoprotein 
4. Prenatal diagnosis allows for early consultation with team (eg, pediatric surgeon, high-risk obstetrician, neonatologist) with expertise managing pregnancies and neonates with abdominal wall defects
5. Goal for delivery of most patients with abdominal wall defects is term vaginal delivery, unless fetal or maternal obstetric indications dictate need for cesarean section 
6. Initial focus of neonatal management is on effective neonatal resuscitation and stabilization followed by protection of exposed viscera from injury and fluid and heat loss before transfer for definitive care
7. Definitive surgical management involves reducing viscera into peritoneal cavity and closing fascia and skin while minimizing risk of further injury to vital organs
8. Overall mortality for survivors born with gastroschisis is about 5% 
9. Patients often require a lengthy hospitalization owing to prolonged postoperative feeding intolerance and requirement for total parenteral nutrition 
10. Long-term prognosis for patients with gastroschisis is good overall and largely dependent on presence of any associated bowel abnormality at birth

Pitfalls

• Prenatal ultrasonography cannot confirm abdominal wall defects until after period of embryonic development during which there is physiologic return of intestine to abdomen (after about 12-14 weeks’ gestation); exception is when herniated liver is detected because this finding is never normal
• Fluid losses in neonates with abdominal wall defects, especially with exposed bowel, are significant and often require 2 to 3 times usual maintenance requirements; careful monitoring of fluid status (eg, urine output, perfusion, vital signs) is important in immediate neonatal period
• Infants with gastroschisis are at risk of developing necrotizing enterocolitis during the first 3 months of life; treat any pneumatosis, feeding intolerance, or bloody stool as presumptive necrotizing enterocolitis
• Failure to pass stool and failure of bilious nasogastric tube output to resolve by 3 weeks may indicate concomitant intestinal atresia

• Gastroschisis is a full-thickness abdominal wall defect usually located to the right of the umbilicus beside normally inserted umbilical vessels 
  • Neonates are born with variable amounts of intestine and occasionally other abdominal organs herniated through the abdominal wall defect
  • No membrane or sac covers the herniated abdominal contents
• Congenital abdominal wall defects are often detected by routine prenatal ultrasonography and/or elevated α-fetoprotein levels 

Classification

Gastroschisis is classified as Simple Gastroschisis and Complex Gastroschisis

• Simple (uncomplicated) 
  • Isolated herniation of bowel without intestinal defects
  • About 85% of neonates born with gastroschisis 
• Complex 
  • Presence of concomitant bowel atresia, stenosis, perforation, volvulus, or necrosis at birth
  • Overall outcome is less favorable than for those with uncomplicated disease 

Clinical Presentation of Gastroschisis

History

• Known prenatal diagnosis is most common presentation

Physical examination

• General finding
  • Neonates are often premature and small for gestational age
  • May present with respiratory insufficiency at birth secondary to concomitant pulmonary hypoplasia or prematurity
• Gastroschisis
  • Full-thickness paraumbilical abdominal defect with no covering membrane
  • Almost always located to the right of a normally inserted umbilical cord
  • Usually 3 to 5 cm in diameter 
  • Umbilical vessels are normally inserted into abdominal wall
  • Herniated abdominal contents depend on defect size
    • Usually contains only midgut
    • May contain stomach, bladder, gonad, or spleen
  • Herniated bowel often appears abnormal
    • May be edematous, thickened, or matted
    • Fibrinous exudate (inflammatory peel) may cover bowel
  • Inspection may reveal evidence of significant vascular compromise or atresia in up to 15% of patients, such as: 
    • Dusky or frank necrotic bowel
    • Twisting of bowel on vascular pedicle consistent with volvulus
    • Suspected area of atresia or stenosis with significant proximal bowel dilation preceding atretic segment

Associated congenital anomalies

• Gastrointestinal anomalies
  • 10% to 20% of neonates with gastroschisis have associated gastrointestinal anomalies 
    • Intestinal stenosis or atresia is most common 
      • Most commonly involves jejunum or ileum 
    • Bowel perforation, volvulus, or necrosis can occur
  • Most result from intrauterine vascular insufficiency to fetal bowel 
    • Timing of vascular insufficiency:
      • Early: at time of gastroschisis development
      • Later: caused by volvulus or compression of mesenteric vasculature against a narrowing abdominal wall ring
• Non‒gastrointestinal-related major defects
  • Serious associated anomalies of other systems and chromosomal abnormalities are uncommon 
  • May occur in up to 10% of patients with gastroschisis 

What Causes Gastroschisis?

• Failure of normal physiologic closure of abdominal wall, which usually occurs early in the embryonic period, results in open defect that allows intestinal herniation 
• Specific underlying cause is postulated but often undetermined
  • Appears to be primarily environmentally triggered 
  • Various theories regarding cause of full-thickness abdominal wall defects include 1 or a combination of insults during embryogenesis, such as: 
    • Localized failure of mesoderm formation
    • Rupture of the amnion at the umbilical ring
    • Abnormal involution of the right umbilical vein
    • Disruption of the right vitelline artery with localized body wall ischemia
    • Abnormal body wall folding

What are the Risk factors of Gastroschisis?

Age

• Neonate
  • Incidence is approximately 3 to 4 per 10,000 live births 
  • Incidence increased 30% worldwide from 1995 to 2012; particularly prevalent among mothers younger than 20 years 

Genetics

• Most cases are sporadic 
• Familial cases of gastroschisis are unusual 
  • May be related to presence of 1 or more single nucleotide polymorphisms in combination with environmental confounders (eg, smoking) (OMIM #230750) 

Ethnicity/race

• Highest prevalence associated with Hispanic and White maternal race 

Other risk factors/associations

• Young maternal age (20 years or younger) 
• Primipara or primigravida 
• Poor maternal diet and low socioeconomic status 
• Poor prenatal care 
• Maternal exposure to certain drugs and medications
  • Vasoconstrictors (eg, phenylpropanolamine, pseudoephedrine) 
  • Analgesics (eg, ibuprofen, salicylates, acetaminophen) 
  • Cigarettes 
  • Illegal drugs (eg, cocaine, heroin) 
• Maternal alcohol consumption 
• Genitourinary infection in the first trimester 

How is Gastroschisis diagnosed?

Primary diagnostic tools

• Prenatal diagnosis (most common)
  • Suspect diagnosis if routine prenatal ultrasonography shows abnormal findings and/or patient has elevated α-fetoprotein level
    • Overall prenatal detection rate is about 90% 
    • Most defects are diagnosed by mid-second trimester 
  • Confirm and characterize abdominal wall defect and associated anomalies (eg, bowel obstruction) with high resolution comprehensive fetal ultrasonography
• Postnatal diagnosis
  • Postnatal physical examination confirms diagnosis and severity of abdominal wall defect
  • Perform detailed systemic examination in all diagnosed neonates to assess for presence of associated anomalies
    • Includes detailed examination of bowel for stenosis, atresia, necrosis, and perforation performed by consulting pediatric surgeon
  • Obtain serial glucose levels in neonates at risk for hypoglycemia
    • Hypoglycemia is common among premature neonates and small-for-gestational-age neonates
  • Obtain other routine studies to guide neonatal resuscitation 
    • Often includes CBC, electrolytes, blood gas, and chest radiograph

Laboratory

• Maternal serum α-fetoprotein
  • Almost always markedly elevated in mother carrying fetus with gastroschisis 

Imaging

• Prenatal ultrasonography performed after first trimester
  • Abnormal findings that suggest possible abdominal wall defect thus prompting high resolution comprehensive fetal ultrasonography include: 
    • Fetal growth abnormalities
    • Amniotic fluid level abnormalities
    • Abdominal wall defect with visceral herniation
  • Test characteristics
    • Reported sensitivity is about 83% 
      • Operator ability 
      • Fetal position: inability to accurately visualize abdominal wall during this screening evaluation, which actually was designed primarily to assess fetal number, position, and gestational age 
    • Highly specific (greater than 95%) for diagnosis when abdominal wall defect is visualized 

Differential Diagnosis

Most common

• Omphalocele
  • Midline abdominal wall defect in which a variable amount of intestine and often other organs (eg, liver) are herniated outside the abdominal wall
    • Defect is most commonly centered in the middle abdomen, and herniated viscera is often covered by a membrane, unless it has ruptured in utero
    • Umbilical vessels insert directly into the membrane instead of the intact body wall
  • Ruptured omphalocele (lacking covering membrane) may be difficult to clinically differentiate from gastroschisis
  • Differences between gastroschisis and omphalocele may include:
    • Location of omphalocele abdominal wall defect is midline; gastroschisis occurs lateral to the umbilicus
    • Omphalocele defects are often larger in diameter (usually larger than 4-10 cm) than gastroschisis defects (usually 2-5 cm)
    • Bowel appearance is often more matted, edematous, and exudative in neonates with gastroschisis compared with ruptured omphalocele (unless rupture occurs early in pregnancy and bowel has been directly exposed to amniotic fluid for a lengthy period)
    • Omphalocele usually is not an isolated anomaly, and comorbid major congenital defects or chromosomal abnormalities commonly occur in association; gastroschisis is usually an isolated anomaly
    • Prolonged ileus is less common in neonates with omphalocele but very common in neonates with gastroschisis
    • Overall mortality is much higher for neonates born with omphalocele (up to 30%) compared with neonates born with gastroschisis (up to 5%)
  • Differentiate based on clinical findings

How is Gastroschisis treated?

• As soon as diagnosed prenatally, consult with team of experts to plan perinatal care and neonatal management strategy at facility with resources appropriate to support neonate
• Primary goal upon delivery is to effectively resuscitate and stabilize neonate while protecting bowel and other exposed viscera from further injury 
• Surgically manage by reducing intestine and viscera into intraperitoneal location, and close fascia and skin while minimizing risk of further injury to vital organs (completed by specialist) 
• Focus on neonate’s nutritional status by using early total parenteral nutrition and carefully advancing enteral feedings (when appropriate) to facilitate safe discharge from hospital and minimize adverse outcomes

Admission criteria

Criteria for ICU admission

• Manage all patients in the neonatal ICU

Recommendations for specialist referral

• At time of diagnosis, consult a multidisciplinary team of specialists with experience managing high-risk pregnancies and neonates with abdominal wall defects; core team includes pediatric surgeon, high-risk obstetrician, and neonatologist 
• Consider consulting clinical geneticist for neonates with gastroschisis—particularly when other major associated anomalies are present—for further diagnostic recommendations and for genetic consultation with family 

Treatment Options

Prenatal and perinatal management

• Team of specialists (eg, pediatric surgeon, neonatologist, high-risk obstetrician) must counsel families about treatment and prognosis of patients with abdominal wall defects 
• Transfer patient to high-risk obstetrician at time of diagnosis for prenatal care, further monitoring, and delivery at tertiary care center that has neonatal ICU with team experienced managing neonates who have complex surgical issues 
• Monitor with serial fetal ultrasonography and stress testing
• Consider using amniotic fluid replacement techniques (eg, amnioinfusion) for severe oligohydramnios; reports of success are varied 
• Goal is term vaginal delivery, unless fetal or maternal obstetric indications dictate need for cesarean section 
  • Mortality and short-term outcomes are not affected by mode of delivery; however, longer duration of pregnancy is associated with increased fetal risk (eg, bowel complications, stillbirth) 
  • Some experts advocate inducing labor during early term period, given increased risks as pregnancy progresses 

Neonatal resuscitation

• Focus initial management on the ABCs of neonatal resuscitation: stabilizing airway, breathing, and circulation
  • Manage according to neonatal resuscitation guidelines for intubation and mechanical ventilation
    • Surfactant replacement may be required for preterm neonates; preterm delivery is not unusual for patients with gastroschisis
  • Obtain IV access to provide aggressive fluid replacement and management
    • Neonates are at high risk for excessive fluid loss from third spacing and from evaporation owing to exposed bowel and increased surface area
    • Upper extremity or scalp veins are preferred for initial peripheral access 
    • Umbilical artery and vein may be cannulated 
  • Warm neonate under radiant heater or in heated incubator 
    • Neonates are at high risk for hypothermia
• Protect viscera from mechanical trauma, minimize heat and evaporative loss, and prevent vascular compromise
  • Apply sterile, warm, saline-soaked gauze or sponge to exposed viscera
  • Cover entire lower extremity in a sterile large plastic bag (ie, bowel bag), or wrap extruded viscera in sterile cling film
  • Position neonate on their right side and stabilize bowel mass in a central position, supporting it from sides and below 
    • This positioning helps avoid kinking of mesenteric vascular pedicle and helps prevent traction on liver vasculature 
• Assess and treat hypoglycemia 
  • Premature neonates and neonates with intrauterine growth restriction are at increased risk for hypoglycemia
• Maintain adequate intravascular volume
  • Neonates with exposed bowel often require at least 2 to 3 times the maintenance fluids that a healthy newborn requires 
• Gastric decompression 
  • Prevent distention and minimize aspiration risk by using nasogastric or orogastric tube to suction or gravity to drain
• Antibiotic prophylaxis 
  • Begin antibiotic prophylaxis with ampicillin and gentamicin in all neonates to decrease risk of sepsis or wound infection
  • Most experts recommend broad spectrum antibiotics in consultation with pediatric surgery and neonatology team
• Extracorporeal membrane oxygenation
  • May attempt as salvage therapy to manage respiratory failure or severe congenital heart disease if medical management fails (rarely required) 
  • Results are better for infants with gastroschisis than for those with omphalocele but carries a high mortality rate 

Immediate management of compromised bowel

• Urgent surgical enlargement of gastroschisis abdominal wall defect is necessary when bowel is strangulated by too small abdominal wall defect 
  • Need to enlarge right-sided defect with incision directly to the right of or superior to and slightly to the left of the defect, taking care not to injure adjacent umbilical vessels and mesentery 
  • Can perform procedure at bedside with local anesthesia and sedation or in the operative suite 
• Urgent manual detorsion of volvulus may be necessary 

Surgical management

• Before definitive repair, carefully assess exposed bowel for atresia, vascular compromise, obstructing bands, perforation, and necrosis 
• Can be difficult to determine appropriate timing for definitive closure of defect
  • In general, definitive repair is considered urgent because gastroschisis defect is essentially an open peritoneal evisceration 
    • Goal for covering extruded bowel loops is 4 to 7 hours after birth for both primary closure and staged procedure 
    • Goal for primary closure is to definitively cover extruded bowel loops 4 to 7 hours after birth 
• Timing and specific definitive treatment is individualized according to size of defect, amount and condition of external bowel, and size and stability of neonate 
  • Simple gastroschisis
    • Many definitive techniques are available
      • Primary closure of abdominal wall defect
        • May be attempted when abdominal cavity is large enough to accommodate viscera without risk of intra-abdominal compartment syndrome
        • Immediate reduction with bedside closure of abdominal wall defect 
          • May be accomplished when herniated bowel is in fairly good condition (eg, minimal matting and inflammatory peel) 
          • Sutureless closure technique may be done by using umbilical cord to bridge any gap in abdominal wall defect 
        • Early reduction with primary operative closure of abdominal wall defect
          • Neonate is taken to operating room when loops are edematous and covered by more significant inflammatory peel
          • Generally, first enlarge defect, then reduce herniated viscera, and finally close
      • Staged closure (ie, silo placement, serial reductions, delayed fascial closure)
        • Necessary when abdominal cavity will not safely accommodate all herniated viscera and when herniated loops are in poor condition (eg, very edematous, tightly matted, covered by thick inflammatory peel) 
          • Involves hanging a silo (ie, extracorporeal bag containing the viscera) from roof of incubator or crib, which allows the viscera to gradually enter the abdominal cavity
          • Bowel reduction may be accomplished by gravity-assisted self-reduction and/or gentle manual reduction
          • Various material (eg, Silastic, Gore-Tex) can be used to construct a silo, and prefabricated silos are available
            • Prefabricated, spring-loaded silo may be put in place at bedside and secured with or without sutures
        • Delayed primary reduction with intraoperative closure 
          • Often involves placing spring-loaded silo in delivery room or at bedside 
          • Silo volume is gradually reduced, and abdominal wall defect is surgically closed in the operating room a few days later 
        • Delayed intraoperative closure with silo sutured in place to fascia
          • Silo volume is gradually reduced once or twice daily with goal of bowel reduction in 7 to 10 days 
          • Neonate is taken to operative suite for removal of silo and surgical closure when viscera is reduced into abdomen
    • Various techniques for fascia and skin closure of abdominal wall may be used 
      • Delayed closure of fascia and/or skin several days after successful bowel reduction into abdominal compartment
      • Use of prosthetic patching of fascia with or without skin closure
      • Closure of wound by secondary intention
        • Umbilical cord tissue may be used as biological dressing, allowing skin and umbilical ring fascia to heal over time
        • Open abdominal wound management is required until epithelialization is complete
        • Definitive repair of abdominal wall is then accomplished at a remote date
      • Vacuum-assisted closure 
  • Complex gastroschisis
    • Bowel atresia
      • Neonates who are good surgical candidates with bowel in good condition
        • Primary repair with resection of atresia and primary anastomosis followed by closure of abdominal wall defect 
        • End stoma for distal atresia and closure of abdominal wall defect; second procedure weeks to months later to perform ileostomy take-down and reconnect bowel 
      • Inflammatory peel and elevated intra-abdominal pressure
        • Often requires staged closure
        • Reduction of unrepaired bowel into abdominal cavity and closure of abdominal wall 
        • Supportive care with total parenteral nutrition and gastric decompression for several weeks until another laparotomy is performed to repair intestinal atresia 
    • Vascular compromise
      • Options depend primarily on condition of bowel
        • Bowel in otherwise good condition without significant inflammatory peel
          • Primary resection with anastomosis or stoma placement followed by closure of abdominal wall defect 
        • Significant coexistent inflammatory peel or bowel wall edema
          • Staged closure may be required
        • Volvulus or bowel strangulation
          • Immediate manual reduction or enlargement of abdominal wall defect may be urgently required 
        • Nonviable bowel
          • Resection of damaged loop and creation of temporary stoma 
      • Bowel transplant is a remote salvage therapy option when other management strategies fail 

Drug therapy

• Dextrose (for hypoglycemia) 
  • Dextrose 10% Solution for Injection; Neonates: 2 to 3 mL/kg bolus, followed with continuous infusion rate beginning at 4 to 8 mg/kg/minute. 
  • Reassess serum glucose after bolus and every 30 to 60 minutes until stable. 
  • Titrate glucose infusion rate to maintain normoglycemia with glucose greater than 40 mg/dL in term and late preterm infants. 
  • Dextrose concentrations up to 25% (D25) may be required to deliver higher glucose infusion rates (15-30 mg/kg/minute); central line is required for glucose infusion concentrations greater than 12.5%. 
  • Consider glucagon infusion for persistently low serum glucose concentrations despite glucose infusion rate of greater than 20 mg/kg/minute, particularly in infants with hyperinsulinism related to Beckwith-Wiedemann. 
• Antibiotics
  • Ampicillin 
    • Ampicillin Sodium Solution for injection; Neonates 34 weeks gestation and younger and 0 to 7 days: 50 mg/kg/dose IV/IM every 12 hours.
    • Ampicillin Sodium Solution for injection; Neonates 34 weeks gestation and younger and older than 7 days: 75 mg/kg/dose IV/IM every 12 hours.
    • Ampicillin Sodium Solution for injection; Neonates older than 34 weeks gestation: 50 mg/kg/dose IV/IM every 8 hours.
    • Ampicillin Sodium Solution for injection; Infants, Children, and Adolescents: 50 to 200 mg/kg/day (Max: 8 g/day) IV/IM divided every 6 hours.
  • Gentamicin
    • Monitor renal function closely in all patients receiving gentamicin. Measure gentamicin serum concentrations if there is a decrease in urine output or a laboratory value that suggests a change in renal function
    • Therapeutic drug monitoring (measurement of gentamicin blood levels to guide therapy) is recommended if drug is given for more than 48 hours, owing to narrow therapeutic index; although initial doses can be recommended, maintenance dosing should be individualized based on pathogen, site of infection, and serum concentrations
    • Gentamicin Sulfate Solution for injection; Neonates 0 to 7 days weighing less than 1.2 kg: 2.5 mg/kg/dose IV/IM every 18 to 24 hours. FDA-approved dosage is 2.5 mg/kg/dose IV/IM every 12 hours.
    • Gentamicin Sulfate Solution for injection; Neonates 0 to 7 days weighing 1.2 to 2 kg: 2.5 mg/kg/dose IV/IM every 12 to 18 hours.
    • Gentamicin Sulfate Solution for injection; Neonates 0 to 7 days weighing more than 2 kg: 2.5 mg/kg/dose IV/IM every 12 hours; extend interval to 18 to 24 hours for neonates on ECMO. Individualize subsequent dosing based on serum concentrations. Dosage adjustment needed after decannulation.
    • Gentamicin Sulfate Solution for injection; Neonates 8 to 29 days weighing less than 1.2 kg: 2.5 mg/kg/dose IV/IM every 18 to 24 hours. FDA-approved dosage is 2.5 mg/kg/dose every 8 hours.
    • Gentamicin Sulfate Solution for injection; Neonates 8 to 29 days weighing 1.2 to 2 kg: 2.5 mg/kg/dose IV/IM every 8 to 12 hours.
    • Gentamicin Sulfate Solution for injection; Neonates 8 to 29 days weighing more than 2 kg: 2.5 mg/kg/dose IV/IM every 8 hours; extend interval to 18 to 24 hours for neonates on ECMO. Individualize subsequent dosing based on serum concentrations. Dosage adjustment needed after decannulation.

Nondrug and supportive care

• Nutrition
  • Patients often experience a lengthy period of adynamic ileus requiring central line for total parenteral nutrition 
  • Begin enteral feeds as soon as bilious gastric drainage diminishes and bowel activity returns 
  • Slow advancement of enteral feedings is required 
    • Maternal breast milk is preferred over formula to reduce risk of necrotizing enterocolitis 
  • Include early oral stimulation to diminish risk of losing suck swallow reflex

Comorbidities

• Extra-abdominal gonad(s)
  • Both the ovaries and testicles may be included in the external viscera 
  • Place into abdominal cavity at time of closure
  • Most testes descend with time; orchiopexy is performed for those that do not descend by 6 months to 1 year 

Monitoring

• Prenatal monitoring
  • Primarily to assess for obstetric indications for delivery
  • Although many fetal monitoring parameters have been studied, few correlate well with morbidity and mortality
  • Surveillance routine is not rigorously established and is often individualized; general prenatal monitoring may include:
    • Estimation of fetal weight can be difficult in fetuses with abdominal wall defects because abdominal circumference cannot be accurately measured
      • Specific formula is available to estimate fetal weight based on biparietal diameter, occipitofrontal diameter, and femur length 
    • Ultrasonography every few weeks to evaluate fetal growth, amniotic fluid, condition of herniated bowel loops, and intra- and extra-abdominal bowel dilation 
      • Diminished intrauterine growth is often detected at end of second or beginning of third trimester 
      • Polyhydramnios with progressive, significant intra-abdominal bowel dilation suggests presence of bowel atresia 
      • Oligohydramnios is common by the end of second trimester; severe oligohydramnios (amniotic fluid index less than 2 cm) is potentially fatal and may require intervention (eg, amnioinfusion) 
      • Extra-abdominal bowel dilation is common and related to circumferential restriction at the level of abdominal wall defect 
    • Fetal nonstress test
      • Weekly for fetuses less than 32 weeks’ gestation with fetal growth or amniotic fluid levels outside reference range, or with progressive bowel dilation 
      • Twice weekly for all fetuses at 32 weeks’ gestation and beyond 
    • Frequency of monitoring is increased when additional complications are found (eg, abnormal amount of amnionic fluid, fetal growth restriction, signs of bowel obstruction)
      • Additional monitoring parameters are dictated by standard obstetric guidelines (eg, measurement of Doppler umbilical artery flow when fetal growth restriction is suspected)
• Monitoring in the immediate neonatal period
  • Vital signs, measures of perfusion, and urine output guide initial resuscitation
    • Monitor fluid status with serial assessment of perfusion and urine output 
    • Monitor routine vital signs with attention to heart rate and mean arterial pressure 
  • Monitor core body temperature and maintain normothermia
  • Regularly monitor levels of electrolytes, blood gases, and glucose with attention to development of hypoglycemia
• Monitoring for complications following definitive closure of abdominal wall defect
  • Significant visceroabdominal disproportion (large amount of herniated viscera compared with underdeveloped abdominal cavity) may result in increased intra-abdominal pressure, leading to abdominal compartment syndrome with diminished perfusion to viscera, including gastrointestinal and renal systems
  • Careful monitoring for intra-abdominal compartment syndrome is required following reduction of viscera and closure of abdominal wall defect
  • Regularly monitor abdominal examinations and pay attention to any signs of obstruction (eg, progressive distention, increase in nasogastric/orogastric output) or necrotizing enterocolitis (eg, abdominal wall discoloration, tenderness, rigidity) 
  • Rising intra-abdominal pressure is primarily reflected by adverse hemodynamic (eg, reduced cardiac output, reduced splanchnic perfusion pressure) and ventilatory effects
    • Intra-abdominal pressure higher than 15 mm Hg is consistent with intra-abdominal hypertension 
    • Intra-abdominal pressure higher than 20 mm Hg is consistent with abdominal compartment syndrome 
  • Various strategies exist to monitor for abdominal compartment syndrome and diminished perfusion to viscera
    • Monitor urine output and peripheral perfusion
      • Lower extremity edema and diminished capillary refill may herald significant caval compression
      • Oliguria and poor peripheral perfusion may be clinical indicators of inability to tolerate closure
        • Goal for urine output is at least 1 mL/kg/hour 
    • Monitor for ineffective ventilation and rising central venous pressure
      • Precipitous need for increased ventilatory support pressures following bowel reduction predicts inability to tolerate closure
      • More than 4 mm Hg increase in central venous pressure is concerning for increased intra-abdominal pressure
    • Consider indirect measurements of intra-abdominal pressure such as intragastric pressure or intravesicular pressure 
    • Consider monitoring for unexplained metabolic acidosis that may result from diminished splanchnic perfusion pressure and/or hepatic venous congestion
  • Findings concerning for increasing intra-abdominal pressure and abdominal compartment syndrome necessitate emergent take down of abdominal wall defect closure and placement of silo 

Complications

• Prenatal complications
  • Intrauterine growth restriction
    • Occurs in 30% to 70% of fetuses 
    • Results in small-for-gestational-age neonates 
  • Oligohydramnios
    • Amniotic fluid replacement techniques may be used with variably reported success 
  • Intrauterine bowel injury
    • May be ischemic
      • Severity of injury can range from focal intestinal atresia to volvulus with loss of entire midgut 
    • May be related to direct exposure of bowel to amniotic fluid
      • Development of diffuse serositis or inflammatory peel on exposed bowel is difficult to predict prenatally
        • Observed in some but not all neonates
        • Severity is highly variable
      • More commonly develops after 30 weeks’ gestation 
        • Prolonged exposure to amniotic fluid often increases severity
  • Premature delivery
    • Spontaneous preterm delivery is common (up to 28% of deliveries of neonates with gastroschisis compared with 6% of routine deliveries) 
    • Fetuses with findings suggestive of intestinal atresia on prenatal ultrasonography monitoring (eg, persistent and progressive intra-abdominal bowel dilation) are at highest risk 
    • Majority of neonates are spontaneously born from 34 to 36 weeks’ gestation 
  • Fetal death
    • May occur as a result of massive in utero volvulus or acute compromise in umbilical blood flow secondary to external visceral bowel mass 
    • Risk is about 5% overall 
      • Higher risk fetuses are those with the following:
        • Fetal growth restriction or small-for-gestational age weight 
        • Compression of umbilical vessels by herniated viscera 
    • Often occurs late in gestation
• Postnatal complications
  • Bowel complications
    • Include intestinal atresia, volvulus, necrosis, or perforation
    • Present in up to 10% to 20% of neonates 
    • Confer increased risk of mortality and complicated clinical course
  • Prolonged ileus with severe dysmotility and nutrient malabsorption
    • Very common and associated with marked small bowel dilation with extremely delayed intestinal transit times 
    • Expect extremely prolonged period of feeding intolerance with total parenteral nutrition required in neonates who: 
      • Have complex gastroschisis
      • Require staged closure of defect
  • Necrotizing enterocolitis 
    • May occur in up to 18.5% of neonates born with gastroschisis 
    • Can occur in postoperative period during advancement of feeds
    • Gradual slow advancement and preferential use of breast milk may reduce risk 
  • Short bowel syndrome 
    • Rare complication from extensive bowel necrosis occurring in utero or in neonatal period
  • Adhesive bowel obstruction
    • Long-term risk is about 5% to 10% 
  • Undescended testis
    • Occurs in 15% to 30% of males 
  • Chronic abdominal pain 
  • Cosmetic concerns about lack of umbilicus and abdominal scarring 
  • Pulmonary hypoplasia and/or pulmonary hypertension
    • Rare in comparison to neonates with omphalocele 
  • Intestinal malrotation
    • Many patients with gastroschisis are born with intestinal malrotation 
    • Malrotation places patient at risk for volvulus
    • Overall risk for volvulus in patients with gastroschisis is lower than in general population born with congenital intestinal malrotation without abdominal wall defect
      • Postoperative adhesions following repair of abdominal wall defects are common and thought to protect from volvulus 
    • Advise parents at discharge that bowel obstruction can occur in childhood
• Surgical complications related to closure of abdominal wall defect
  • Intraoperative
    • Iatrogenic injury to bowel or other abdominal organs 
    • Vascular compromise from kinking of the vasculature 
  • Postoperative
    • Abdominal compartment syndrome 
      • Compromised perfusion to vital abdominal organs (eg, bowel, kidneys) and caval compression cause risk for intestinal necrosis with necrotizing enterocolitis and/or sepsis, acute renal failure, hepatic congestion, wound dehiscence, or inability to ventilate 
      • Defined as intra-abdominal pressure greater than 20 mm Hg or presence of symptoms or signs related to intra-abdominal hypertension such as decreased cardiac output, oliguria, metabolic or respiratory acidosis, and raising hepatic transaminases
    • Fistula formation (eg, enteroenteric, enterocutaneous)
    • Hernia
      • Ventral and/or inguinal hernia are more common after skin flap or nonoperative management strategies 
• Silo complications
  • Silo dislodgement 
    • Must be careful to avoid excessive pressure on silo contents to avoid dislodging silo
  • Spring-loaded silo complications 
    • Can cause or require enlargement of fascial defect
    • Requires mesh for abdominal closure

Prognosis

• Outcome is largely dependent on severity of associated bowel injury
  • Overall survival is up to 95% 
  • Most early mortality is related to massive bowel loss or intestinal necrosis with sepsis 
    • About 50% of neonates who require extracorporeal membrane oxygenation survive until discharge 
  • Most late-onset morbidity and mortality is related to need for prolonged total parenteral nutrition with resultant cholestatic disease or central line sepsis 
  • Long-term gastrointestinal function is usually good despite common early feeding intolerance associated with dysmotility
  • Long-term neurodevelopmental and growth outcomes among survivors are similar to gestational age-matched controls 
  • Mortality is considerably higher in patients with a course complicated by any of the following:
    • Preterm delivery 
    • Necrotizing enterocolitis 
    • Pulmonary hypoplasia, bronchopulmonary dysplasia, or pulmonary hypertension
• Simple gastroschisis
  • Primary reduction and closure is possible in about 70% of these neonates 
  • Successful primary reduction is associated with less time to full feeding tolerance, fewer complications, and shorter hospitalization than patients with complicated disease 
• Complex gastroschisis
  • Outcomes are often less favorable compared with neonates who have uncomplicated disease 
    • Overall survival drops to approximately 70% and morbidity is higher among patients with complicated disease
  • Tend to be born earlier and at lower birth weights than those with uncomplicated disease 
  • More likely to require multiple operations and require longer course of total parenteral nutrition than those with uncomplicated disease 
  • Delayed feeding tolerance is very common; associated dysmotility is common
    • Lengthy hospitalization is often required to allow for gradual advancement and tolerance of enteral feeds
      • Up to 36% of neonates with complex gastroschisis require hospitalization for 1 to 2 months, and 25% require hospitalization for more than 2 months 

Screening

At-risk populations

• Most abdominal wall defects are sporadic; therefore, all pregnant women may be at risk for affected neonate
  • Women with a history of delivering an infant with gastroschisis may be at greater risk for neonates with specific abdominal wall defects in subsequent pregnancies 

Screening tests

• Routine maternal screening tests
  • Maternal serum α-fetoprotein level
    • Blood test is routinely obtained between 15 and 20 weeks’ gestation to screen for neural tube defects, chromosomal abnormalities, and other defects
    • Levels are almost always markedly elevated with gastroschisis 
    • If levels are increased, high-resolution comprehensive fetal ultrasonography and possibly amniocentesis are indicated
  • Standard fetal ultrasonography
    • Used for general screening to assess gestational age and detect fetal abnormalities; not required in prenatal care of routine, low-risk pregnancies, although frequently obtained
    • Indicated in routine care of pregnant patients with a higher risk of neural tube defects and other congenital defects, assisting in the screening of these patients along with maternal serum α-fetoprotein
    • If abnormalities are detected (eg, possible abdominal wall disruption with visceral herniation, abnormal fetal growth parameters, abnormal amniotic fluid levels), high-resolution comprehensive fetal ultrasonography is indicated

References

1: Ledbetter DJ: Congenital abdominal wall defects and reconstruction in pediatric surgery: gastroschisis and omphalocele. Surg Clin North Am. 92(3):713-27, x, 2012  Reference