12.1 Neonatal & Pediatric Surgical Abdomen (NEC, Malrotation with Volvulus, Intussusception, Appendicitis)

Neonatal and Pediatric Surgical Abdomen

Quick answer: Suspected necrotizing enterocolitis (NEC) calls for bowel rest, decompression and close reassessment. Bilious emesis in an infant calls for immediate assessment for obstruction, including malrotation with volvulus. Stable ileocolic intussusception usually undergoes image-guided enema reduction. Appendicitis risk assessment determines who needs observation, ultrasound, or prompt surgical consultation.

Necrotizing enterocolitis

Prematurity is a major risk factor. Immature barrier and immune function, microbial dysbiosis and disturbed perfusion can converge to injure the bowel wall. NEC can progress from inflammation and intramural gas to necrosis, perforation and systemic shock. Residuals, distension and blood in stool alone are nonspecific. Consider sepsis-associated ileus, spontaneous intestinal perforation (SIP), and other causes of neonatal obstruction or bleeding. SIP is a distinct, often focal perforation in a very preterm infant, sometimes with free air and little or no pneumatosis. Interpret imaging with the age, course and exam.

Pneumatosis is gas within the bowel wall and can look linear or bubbly. Portal venous gas branches toward the hepatic periphery. A lateral decubitus or cross-table view can help detect free air. Obtain abdominal radiographs promptly and repeat based on severity and trajectory. In equivocal cases, expert bowel ultrasound can evaluate wall perfusion, intramural or portal gas, and abnormal fluid. A fixed loop or portal gas raises concern. The surgical decision also weighs serial exam, perfusion, platelet and acid-base trends, and other evidence of compromised bowel. Modified Bell criteria · UNC neonatal NEC pathway · ERNICA surgical NEC guideline

Initial care. Hold enteral feeds, decompress the stomach, obtain blood culture if feasible without delaying treatment, and give empiric IV antibiotics. Support perfusion with reassessed resuscitation, monitor glucose, urine output, acid-base status and platelets, and plan parenteral nutrition if bowel rest will continue. Consult neonatology and involve pediatric surgery early for definite or progressive disease. A local neonatal regimen may start with ampicillin and gentamicin, with anaerobic coverage in more severe disease or perforation. Select and adjust coverage for local resistance, renal function, cultures and source control. As one U.S. pathway example, a resolving stage I rule-out uses about 48 hours of antibiotics, medical stage IIA 7 days and IIB 10 days. Advanced disease, bacteremia or inadequate source control may change duration. Cohort data on anaerobic therapy differ between medical and surgical disease. UNC neonatal NEC pathway · Anaerobic therapy cohort

Source control and feeding. Pneumoperitoneum in NEC needs urgent surgical assessment for source control. Progressive shock, peritonitis or acidosis can warrant exploration even without free air. Surgeons may choose laparotomy or bedside drainage based on the suspected diagnosis, physiology and resources. Drainage can be a bridge, with reassessment for subsequent laparotomy. In the U.S. NEST trial in extremely low-birthweight infants, death or neurodevelopmental impairment at 18–22 months was similar overall (69% after initial laparotomy versus 70% after drainage). The prespecified suspected-NEC subgroup favored laparotomy (69% versus 85%, with uncertainty in the relative risk estimate). Isolated perforation showed a different pattern. Use the likely diagnosis and infant's condition, beyond weight alone. Restart small feeds with the neonatal and surgical teams after improvement and assessment for ongoing disease or obstruction. A small medical NEC cohort supports considering earlier refeeding after recovery. For surgical NEC, ERNICA conditionally suggests starting within 7 days when ongoing disease and obstruction are absent. NEST randomized trial · Medical refeeding cohort · ERNICA guideline

Malrotation and midgut volvulus

A narrow mesenteric base in malrotation allows the midgut to twist around the superior mesenteric vessels, compromising venous return and then arterial supply. Ladd bands can also obstruct the duodenum. Green emesis can precede abdominal distension or tenderness. Pain, blood in stool, poor perfusion or peritonitis raise concern for ischemia. Hold feeds, decompress, establish access, resuscitate according to perfusion, and notify pediatric surgery immediately. Give IV antibiotics when ischemia, perforation or sepsis is suspected. Do not delay surgical action for imaging in a deteriorating infant with peritonitis or strong evidence of volvulus.

In a stable infant older than 2 days with suspected malrotation, urgent upper GI (UGI) fluoroscopy is usually appropriate. An abnormal duodenojejunal junction or a corkscrew course supports the diagnosis. Rapid expert ultrasound can be first in an established pathway. A whirlpool of bowel and vessels around the superior mesenteric artery supports volvulus, and isolated artery/vein orientation cannot exclude it. Discuss a nondiagnostic ultrasound and ongoing concern with the surgeon and radiologist and obtain urgent UGI when appropriate. A normal plain radiograph does not exclude volvulus. In the first days of life, radiographs help distinguish proximal and distal obstruction. A classic double bubble with little or no distal gas strongly suggests proximal duodenal obstruction, often duodenal atresia. Distal gas or an atypical pattern warrants further assessment for causes including malrotation. A convincing ultrasound for volvulus can lead directly to surgery under an established pathway.

At surgery, the Ladd procedure detorses the volvulus, typically counterclockwise, divides obstructing bands and widens the mesenteric base. Viability is assessed and clearly nonviable bowel may require resection. The bowel is positioned with small bowel on the right and colon on the left. Appendectomy is commonly considered because the appendix is now in an atypical position, and practice varies. ACR vomiting in infants · Texas Children's ultrasound-first pathway study · Pediatric Ladd outcomes study · Pediatric surgical practice survey

Ileocolic intussusception

The proximal segment (intussusceptum) telescopes into the receiving segment (intussuscipiens), dragging the mesentery and impairing venous drainage. Episodic pain, pallor, vomiting or unexplained lethargy can be the first clue. Blood and mucus may appear late. A palpable mass can support suspicion, and waiting for the entire triad delays care. Most cases in young children are idiopathic. Atypical age, repeated recurrence or a visible lesion raises concern for a lead point such as Meckel diverticulum, polyp, duplication cyst or lymphoma. IgA vasculitis can also cause intussusception through bowel-wall edema or hemorrhage.

Ultrasound is the first-line study, with a transverse target and longitudinal pseudokidney appearance. A negative bedside study with ongoing suspicion needs formal evaluation. In a stable child with ileocolic disease and no peritonitis or free air, arrange image-guided air or liquid enema with radiology and surgical backup. Local expertise and equipment determine the method. Persistent shock, perforation or peritonitis requires resuscitation and emergency surgical management. Short, transient small-bowel intussusceptions are managed differently from ileocolic disease.

A partial first reduction may be followed by a delayed repeat enema if the child remains stable and has no peritonitis. Failed reduction, perforation or a suspected lead point requires surgical input. Selected children after uncomplicated reduction can feed and go home after observation (about 4 hours in one U.S. pathway) with recurrence precautions and reliable follow-up. Admit or observe longer for persistent symptoms, complex reduction or difficulty returning promptly. APSA management review · CHOP ileocolic pathway · Children's Minnesota guideline

Appendicitis

Migrating pain, focal right lower quadrant (RLQ) tenderness and pain with movement raise suspicion. Preschool children may instead have diffuse pain, fever, vomiting or diarrhea, and delays increase the likelihood of perforation. The chart shows the trend within a single Brooklyn hospital cohort of 180 children younger than 5 with diagnosed appendicitis. Its age-specific rates vary across settings. In adolescents, assess pregnancy possibility and consider other urgent causes such as ovarian torsion.

Pediatric Appendicitis Score (PAS), 10 possible points. Give 2 each for RLQ tenderness and RLQ pain with cough, percussion or hopping. Give 1 each for migration, anorexia, nausea or vomiting, fever, WBC above 10,000/µL, and absolute neutrophil count above 7,500/µL in the cited U.S. pathway. For example, a 9-year-old with migration, vomiting, RLQ tenderness and hopping pain, with no other score findings, scores $1+1+2+2=6$. In that pathway a score of 4–6 prompts ultrasound and reassessment. PAS was developed in children aged 4–15. An age-appropriate score and clinical trajectory guide assessment, especially in preschoolers whose symptoms may be difficult to elicit. PAS derivation · Johns Hopkins All Children's pathway · Brooklyn preschool cohort

Alvarado score. Give 2 each for RLQ tenderness and leukocytosis, and 1 each for migration, anorexia, nausea or vomiting, rebound pain, fever, and the differential finding historically described as a left shift in the original score. Unlike PAS, this score gives extra weight to leukocytosis and uses rebound pain instead of pain with cough, percussion or hopping. Use clinical risk tools within their validated populations and local pathways. Original Alvarado score · Pediatric prospective comparison

Imaging and disposition. Low clinical risk often needs observation and safety-netting without imaging. Intermediate risk generally warrants graded-compression ultrasound. A blind-ending, noncompressible appendix with an outer diameter greater than 6 mm supports appendicitis, especially with hyperemia or surrounding inflammation. Interpret a borderline diameter with the other findings. An unvisualized appendix requires interpretation of secondary signs and the clinical exam. Persistent concern after equivocal ultrasound may warrant MRI or contrast-enhanced CT. Suspected abscess or obstruction can favor contrast-enhanced CT. In high-risk or peritonitic children, contact surgery early. ACR suspected appendicitis in children

Treatment. Laparoscopic appendectomy with preoperative antibiotics is standard operative care. Antibiotics alone can be discussed for selected uncomplicated cases under a surgical pathway. In a multicenter randomized trial of children aged 5–16, one-year treatment failure was 34% with antibiotics versus 7% with appendectomy, using the trial's prespecified definitions. Diffuse peritonitis or sepsis requires urgent source-control evaluation. A stable child with a localized abscess or phlegmon may undergo early surgery or receive IV antibiotics with selective image-guided drainage. After successful nonoperative treatment, interval appendectomy is individualized. The CHINA trial supports observation as an option in selected children after an appendix mass resolves. Pediatric randomized trial · WSES guideline · CHINA randomized trial