Necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a dangerous hemorrhagic inflammation of the intestinal wall that most often affects premature infants. Typical symptoms include abdominal distension, gastric retention, tenderness, rectal bleeding, and visible intestinal loops lacking peristalsis. A radiographic finding of gas within the wall of the intestine (pneumatosis intestinalis) confirms the suspected diagnosis. Conservative management of the condition involves parenteral nutrition and antibiotics. In the case of advanced NEC and intestinal perforation, however, surgery is necessary.

• Hemorrhagic necrotizing inflammation of the intestinal wall
• Most commonly affects the distal ileum and proximal colon

• NEC is the most common cause of acute abdomen in premature infants. ^[1]
• Peak incidence: 2^nd–4^th week after birth ^[2]

Epidemiological data refers to the US, unless otherwise specified.

• The causes of necrotizing enterocolitis are not fully understood but multiple factors contribute to the development of the condition.
  • Intestinal wall perfusion and motility disorders
  • Defective or underdeveloped immune system
  • Intestinal microbial overgrowth
  • Formula feeding
  • Rapid increase of enteral nutrition

References:^[3][4][5][6]

References:^[7][8]

Laboratory tests

• Complete blood count:
  • Neutrophil counts < 1500/μL are associated with a poor prognosis.
  • The degree of thrombocytopenia correlates with the severity of NEC.
• ↑ Inflammatory markers
• Check for signs of DIC → see disseminated intravascular coagulation
• Arterial blood gas analysis: Metabolic acidosis is associated with advanced NEC.
• Blood culture

Imaging ^[9]

• Abdominal radiography
  • Pneumatosis intestinalis: bubbles of gas within the wall of the intestine
  • Portal venous gas (pneumatosis hepatis)
  • Increased intestinal wall thickness
  • Dilated intestinal loops
  • Air‑fluid levels
  • Pneumoperitoneum as a result of intestinal perforation
• Abdominal ultrasound
  • Indication: Ultrasound may be helpful for diagnosing NEC when abdominal radiography is inconclusive.
  • Findings
    • Pneumatosis intestinalis
    • Portal venous gas
    • Increased intestinal wall thickness
    • Decreased intestinal wall perfusion

References:^{[8][10][11][12][13]}

References:^[14][15]

The differential diagnoses listed here are not exhaustive.

Treatment should be initiated promptly when NEC is suspected to prevent complications such as perforation, peritonitis, and sepsis.

• Supportive care:
  • Stop enteral feeding → parenteral feeding and substitution of fluids
  • Gut decompression via nasogastric tube
• IV broad-spectrum antibiotics: e.g., ampicillin, gentamicin, and metronidazole for anaerobic coverage
• Radiographic monitoring: plain supine abdominal radiographs every 6–12 hours in the initial phase of the disease
• Surgery: primary peritoneal drainage and/or laparotomy with necrotic bowel excision
  • Indications: perforation, peritonitis and/or clinical worsening despite medical therapy

References:^[16][17]

• Intestinal perforation:
  • Abdominal radiography: pneumoperitoneum
  • Treatment: surgery
• Short bowel syndrome
• Peritonitis
• Sepsis

References:^[17]

We list the most important complications. The selection is not exhaustive.

Mortality rate: approx. 10–30%

References:^[18][19]

Breast milk has a protective effect