Necrotising Enterocolitis Flashcards
What is necrotising enterocolitis (NEC)?
Necrotising enterocolitis (NEC) is a disorder affecting premature neonates, where part of the bowel becomes necrotic. It is a life threatening emergency. Death of the bowel tissue can lead to bowel perforation. Bowel perforation leads to peritonitis and shock.
What are the risk factors for developing NEC?
The cause of necrotising enterocolitis is unclear. There are certain risk factors for developing NEC:
- Very low birth weight or very premature
- Formula feeds (it is less common in babies fed by breast milk feeds)
- Respiratory distress and assisted ventilation
- Sepsis
- Patient ductus arteriosus and other congenital heart disease
What are the symptoms of NEC?
- Intolerance to feeds
- Vomiting, particularly with green bile
- Generally unwell
- Blood in stools
What are the signs of NEC?
- Abdominal distension
- Reduced bowel sounds
- Palpable abdominal mass
- Visible intestinal loops
- Signs of sepsis
What investigations should be ordered for NEC?
- Blood tests
- FBC
- CRP
- Capillary blood gas
- Blood culture
- Abdominal X-Ray
What is the gold standard test for diagnosing NEC?
Abdominal X-ray.
What may the FBC show for NEC?
Thrombocytopenia and neutropenia.
What may the capilary blood gas show for NEC?
Metabolic acidosis.
What can be shown on the x-ray for NEC?
Xrays can show:
- Dilated loops of bowel
- Bowel wall oedema (thickened bowel walls)
- Pneumatosis intestinalis is gas in the bowel wall and is a sign of NEC
- Pneumoperitoneum is free gas in the peritoneal cavity and indicates perforation
- Gas in the portal veins
What position should the x-ray be taken in for NEC?
This is done front on in the supine position (lying face up). Additional views can be helpful, such as lateral (from the side with the patient on their back) and lateral decubitus (from the side with the neonate on their side).
What sign is present if the bowel has perforated?
If the bowel has perforated, Rigler’s sign may be visible. This occurs when both sides of the bowel wall are visible due to the presence of gas inside the lumen and within the peritoneal cavity.
What is shown in the image?
X-ray of an infant with necrotising enterocolitis.
Briefly describe the management for NEC
Neonates with suspected NEC need to be nil by mouth with IV fluids, total parenteral nutrition (TPN) and antibiotics to stabilise them. A nasogastric tube can be inserted to drain fluid and gas from the stomach and intestines.
NEC is a surgical emergency and requires immediate referral to the neonatal surgical team. Some neonates will recover with medical treatment. In others, surgery may be required to remove the dead bowel tissue. Babies may be left with a temporary stoma if significant bowel is removed.
What % of neonates require surgery for NEC?
20-25%.
What are the first-line antibiotics for NEC?
Broad-spectrum cover is recommended as first-line, such as cefotaxime and metronidazole.
What is the most common emergency surgery for neonates?
NEC.
What are the complications of NEC?
Approximately one in four infants who develop NEC will require surgery. Of those, a 29% post-surgical mortality has been reported at one year.
General complications of NEC include:
- Bowel perforation
- Disseminated intravascular coagulation
- Sepsis
Post-operative complications of NEC include:
- Short bowel syndrome
- Formation of intestinal strictures
- Enterocolic fistulae
- Abscess formation
What differentials should be considered for NEC?
- Sepsis
- Intussusception
- Volvulus
- Hirschsprung’s disease
How does NEC and sepsis differ?
Sepsis can develop as a complication of NEC. NEC has a specific presentation on abdominal X-ray.
Common causes of neonatal sepsis include group B strep infection, premature or prolonged rupture of membranes, chorioamnionitis and maternal septicaemia
How does NEC and intussusception differ?
Intussusception occurs in infants aged between 3 months and 3 years; it is rare in infants. NEC tends to occur in the first 2 weeks of life.
How does NEC and Hirschsprung’s differ?
Hirschsprung’s can cause failure to pass meconium in the first 48 hours of life, NEC does not cause this
