Neonatal surgical emergencies can occur after discharge from the newborn nursery. They are often life-threatening and require prompt evaluation, stabilization, and emergent referral to a pediatric surgeon. Three such conditions are necrotizing enterocolitis (NEC), malrotation with midgut volvulus, and Hirschsprung’s disease.

NEC is the most common gastrointestinal emergency and the most common cause of intestinal perforation in the newborn period.¹ It is usually a disease of preterm infants with low birth weight,² although nearly 5% to 15% occur in term infants.^2–4 Term infants are more likely than their preterm counterparts to have predisposing risk factors^2–5 (Table 46-1). A recent trial showed that the administration of probiotics did not impact the risk of developing NEC in preterm infants.⁶ The vast majority of term infants with NEC have some underlying illness.⁵ Over 90% of full-term infants with NEC present within the first 4 days of life, and the disease tends to advance more rapidly than in preterm infants.⁵ Mortality rates of infants with NEC have been reported between 12% and 30%.^2,4 The diagnosis of NEC is based upon a three-stage classification system.^7,8 Stage I is suspected disease; Stage II is definite disease; and Stage III is advanced disease (Table 46-2).

The development of NEC is multifactorial. Enteral intake in the presence of reduced blood flow and bacteria leads to mucosal inflammation and ulceration.⁹ A compromise in the intestinal mucosal barrier allows bacteria to spread, leading to intestinal perforation, necrosis, and the development of sepsis.¹⁰

SIGNS AND SYMPTOMS

A high index of suspicion should be maintained, because clinical findings of early-stage disease are nonspecific. Infants present with feeding intolerance, decreased activity, vomiting, and diarrhea.¹¹ Abdominal examination findings in mild or early disease may be limited to distention, which is the most common presenting sign.¹² Typically, it rapidly progresses to peritonitis, with bilious emesis, abdominal tenderness, and grossly bloody or guaiac-positive stool.¹³ Erythema or ecchymosis of the abdominal wall occur late in the course of disease. Although some patients experience spontaneous improvement and resolution, many develop signs of disseminated intravascular coagulation (DIC), shock, respiratory failure, and eventually death.¹²

DIAGNOSTIC EVALUATION

The diagnosis of NEC can be confirmed by abdominal radiographs if gas within the bowel wall (pneumatosis intestinalis) or portal venous gas is seen (Fig. 46-1). Finding free air in the abdominal cavity indicates that a perforation has occurred. The presence of a sentinel loop indicates necrotic bowel. Ultrasound can be helpful as an ancillary investigation assisting in the management after the admission to a critical care unit.

Blood tests should be used to identify complications caused by advanced disease such as electrolyte abnormalities, consumptive coagulopathy, or sepsis. In these infants, the WBC may be low due to sepsis, and thrombocytopenia signals the presence of DIC. Blood glucose instability may occur, and blood gas abnormalities are found with sepsis and shock. Blood cultures are positive in approximately 30% of patients with NEC.³

MANAGEMENT

The initial ED evaluation focuses on identifying patients with intestinal perforation, peritonitis, shock, or sepsis. Aggressive and prompt management of these complications are essential and may be life-saving. The managements of shock and DIC are described in Chapters 20 and 106, respectively. Infants with suspected NEC should be treated with a broad-spectrum antibiotic regimen. Concurrent with stabilization of life-threatening conditions, emergent admission to a critical care unit and referral to a pediatric surgeon are indicated. Supportive care includes a nasogastric tube for gastric decompression, NPO status, and ongoing intravenous fluid and electrolyte therapy.

Malrotation is a failure of completion of the embryonic rotation of the gastrointestinal tract. It may result in the suspension of a portion of bowel from a narrow pedicle. Patients with this narrow supporting foundation are at risk for volvulus, which is the twisting of the bowel and its vascular supply, resulting in obstruction and ischemia.¹⁴