Samir K. Gadepalli
James D. Geiger
Presentation
You are called to the delivery room of a newborn male with abdominal contents open to air. The term baby was born via vaginal delivery and had APGARs of 9 and 9 at 1 and 5 minutes, respectively. Prenatal events were significant for polyhydramnios and echogenic bowel seen on fetal ultrasound. Mother is an otherwise healthy 19-year-old G1P1 on prenatal vitamins. On examination, the child weighs 3.1 kg, has normal vital signs, and is in no acute distress. Abnormal physical examination findings include an open, mildly sunken fontanelle, intestinal contents seen protruding from a small 1- to 2-cm defect to the right of an intact umbilical cord without any covering, and bilateral undescended testicles.
Differential Diagnosis
Abdominal wall defects are found in 1 of 5,000 live births. Differences between an omphalocele and gastroschisis are highlighted by location of defect, structures seen outside, presence of a sac, and associated anomalies (see Table 1). Omphaloceles are found in the midline, have an amniotic sac as a cover, contain the intestine, often liver and other abdominal organs, and are within the umbilical stalk. Associated anomalies may include midline defects, such as cardiac or bladder/cloacal, and syndromes such as Beckwith-Weidemann (BW) or trisomy 13, 18, or 21. Prognosis and mortality vary with the presence of associated anomalies, especially the severity of any congenital heart disease and the size of the omphalocele. Gastroschisis is almost invariably found to the right of the umbilicus with only intestinal contents, without a sac, and associated anomalies, such as jejunalileal atresias, gastroesophageal reflux, or undescended testicles.
TABLE 1. Differences Between Omphalocele and Gastroschisis
Workup
In patients with an omphalocele, the presence of associated anomalies must be excluded quickly. Bladder extrophy or Pentalogy of Cantrell can be readily seen on physical exam. Abnormal blood glucose and examination revealing an enlarged tongue can help identify BW syndrome, followed by an echocardiogram and renal ultrasound to find cardiac and renal anomalies, respectively. Chromosomal and prenatal amniocenteses are also helpful in certain situations. Spinal ultrasound and skeletal survey help to identify neural tube or musculoskeletal defects.
About 10% of gastroschisis patients are considered complicated with associated intestinal atresias. Atresia may be identified at the initial examination of the intestine, but if thickened, this can be difficult. Abdominal x-rays and contrast studies aid in confirming intestinal atresias. In patients with gastroschisis, necrotizing enterocolitis is more common and can be identified using physical (abdominal distension, apnea, bradycardia, desaturations, abdominal wall erythema), laboratory (elevated white blood cell count, decreasing platelet counts), and radiographic (pneumatosis, portal venous gas, pneumoperitoneum) characteristics.
Diagnosis and Treatment
Priorities in the management of gastroschisis are to establish coverage for the intestinal contents, resuscitate and maintain intravascular volume, identify associated anomalies, and provide nutrition. At birth, intestinal coverage can be obtained with a bowel bag covering the entire baby until resuscitation has been completed. It is also important to make sure the mesentery is not twisted and the bowel is supported to avoid traction on the mesenteric vessels. Babies are usually born in a dehydrated state and are prone to further volume losses secondary to exposure of intestines; therefore, placing warm towels or a bowel bag can keep the intestines moist while maintaining body temperature.
Resuscitation involves placing an intravenous (IV) line and starting fluids usually at 150 mL/kg/d. Establishing an IV can be a challenge, and occasionally, an intraosseous, saphenous vein cutdown, or central-line venipuncture may be required. Once fluids are started, electrolytes must be closely followed to ensure abnormalities can be quickly corrected. Finally, a nasogastric tube and a Foley catheter serve as usual adjuncts, especially when complete reduction of intestinal contents is attempted.
Establishing nutrition and achieving goal enteral nutrition in patients with gastroschisis remains a challenge. Associated anomalies, such as intestinal atresia, can complicate the management of gastroschisis and are not always diagnosed at birth. The presence of matted, thickened bowel is not uncommon and the presence of an atresia can go unrecognized prior to final closure. Intestinal function is usually delayed in these patients, complicating the picture. A contrast study can help identify if an atresia exists, while parenteral nutrition is provided until intestinal continuity can be reestablished. When enteral nutrition is initiated, periods of intolerance are common and slow steady advancement is preferred. Bilious aspirates do not always reflect an obstruction as bile reflux and gastroparesis are common. Emesis is a better indicator of feeding intolerance but also may represent a sign of developing necrotizing enterocolitis, which can occur more frequently in this population (Figure 1).
FIGURE 1• Different types of gastroschisis defects represent the variation in bowel morphology.
Surgical Approach
After an IV is established, options for reduction of contents and abdominal wall closure can be considered. Options for closure are placement or construction of a silo with gradual reduction of contents until abdominal domain is reestablished versus primary closure with or without the use of a patch (biologic or mesh). A nasogastric tube and rectal tube with irrigation can be used to decompress the bowel to increase room in the peritoneal cavity. A key component for the decision is the creation of an abdominal compartment syndrome. If upon reduction of abdominal contents, the peak pressures increase dramatically or increased tension is required to close the wound, the prudent approach would be placement of a silo and gradual reduction (Figure 2).
FIGURE 2 • The bowel can be placed in a silo, partially reduced, or primarily closed.
The key steps in abdominal closure are decompressing the bowel, running the bowel to identify any atresias or perforations, undermining the fascia, closure of the fascia and skin, and creation of an umbilicus (Table 2). Potential pitfalls include perforation of the bowel, which is fragile in its matted, exposed state; therefore, maneuvers to decompress the bowel should be limited to irrigation and gentle manipulation. Another pitfall is the closure of the defect under tension, which can create an abdominal compartment syndrome with respiratory compromise, decreased urine output, and potential intestinal ischemia and dehiscence.
TABLE 2. Key Technical Steps and Potential Pitfalls to Abdominal Wall Closure
Special Intraoperative Considerations
As suggested above, the presence of an atresia can dramatically change the course of the operation. Options for management when an atresia is encountered include resection and primary anastomosis, creation of an ostomy, and reduction with delayed management of the atresia in a second operation. The strategy chosen is determined by the overall status of the patient, condition of the bowel, and presence of other anomalies.
In a patient with matted, edematous, thickened bowel, creation of an ostomy may not be a feasible option, and with a large-size discrepancy between proximal and distal segments, reduction of contents and returning for a second surgery may be the ideal option. Babies can be easily decompressed for several weeks with an atresia allowing for improvement in the quality of the bowel and allow the child to grow on parenteral nutrition. If the liver is severely affected by parenteral nutrition, the child has poor weight gain and growth, or the bowel cannot be adequately decompressed for the time period, an operation is warranted sooner; otherwise, 6 to 8 weeks is a commonly chosen endpoint to avoid inflammatory adhesions and bowel injury at re-operation.
Postoperative Management
Feeding intolerance is a common problem in gastroschisis secondary to any combination of gastroesophageal reflux, gastroparesis, intestinal dysmotility, shortened intestinal length, and bacterial overgrowth increasing the potential for necrotizing enterocolitis. The presence of an atresia must be excluded using a contrast study. If bacterial overgrowth is suspected from recurrent episodes of enterocolitis or malabsorption, cycling enteral antibiotics can be useful. Gastroesophageal reflux and dysmotility can usually be addressed with nonoperative measures including elevation of the head, small and frequent meals, histamine blockers, proton pump inhibitors, and promotility agents, such as metoclopramide or erythromycin. Occasionally, a combination of partial parenteral and enteral nutrition is required.
Wound infection and dehiscence are common complications to anticipate after gastroschisis closure. Close observation of the wound and perioperative antibiotic use are essential steps in the closure. Frequently, undermining the wound creates an area of erythema and ecchymosis around the wound and increases concern of infection especially after a period of initial silo placement. Delayed closure of the skin is useful when mesh is not exposed on the underlying fascia and there is tension present on the skin during initial closure.
TAKE HOME POINTS
· Fundamentals in the management of gastroschisis at birth include coverage of intestinal contents, maintenance of body temperature, and early, aggressive resuscitation.
· The presence of liver in a midline abdominal wall defect is likely to be an omphalocele.
· Intestinal atresias can occur in 10% of patients and pose a significant challenge to the management of patients with gastroschisis.
· Abdominal compartment syndrome can occur with aggressive attempts at reduction of intestinal contents and abdominal wall closure and can be prevented with gradual reduction.
· Wound breakdown and feeding intolerance are common postoperative problems that require carefully throughout management strategies.
· Mortality is <10% and in general occurs as a result of intestinal failure and complications of total parenteral nutrition.
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