Necrotising Enterocolitis ✅ Flashcards
What % of VLBW infants will develop NEC?
15-25%
How is a diagnosis of NEC made?
Clinical diagnosis
How does NEC present?
- Abdominal distention and tenderness
- Bilious aspirates
- Bloody stools
What is found on AXR in NEC?
Intramural air (pneumatosis intestinalis)
What can NEC progress too?
Peritonitis and bowel perforation
What causes NEC?
Exact cause unknown, but probably multifactorial including loss of bowel mucosal integrity
What does a loss of bowel mucosal integrity lead to?
Macromolecular absorption and bacterial translocation
What is there a significant deficiency of in NEC?
Secretory IgA
Does NEC increase the permeability of the intestine to small or large molecules?
Both
What can reduce the risk of NEC?
Antenatal glucocorticoid therapy
Why does antenatal glucocorticoid therapy reduce the incidence of NEC?
It improves intestinal maturation and reduces permeability
What may initiate the process in NEC?
Infection
How may infection initiate the process in NEC?
By causing mucosal injury leading to invasion of gas producing bacteria
What can invasion of the bowel mucosa with gas-producing bacteria result in?
Pneumatosis intestinalis
What gas is in the bowel wall in NEC?
Mainly nitrogen and hydrogen
Other than the bowel wall, where may gas be found in NEC? -
In the portal venous system
What is found histologically in NEC?
Necrosis of the mucosa with;
- Microthrombus formation
- Patchy mucosal ulceration
- Oedema
- Haemorrhage
What substances play an important role in the pathogenies of NEC?
- Cytokines
- Inflammatory markers
What inflammatory markers play an important role in NEC?
- Interleukins
- Tumour necrosis factor alpha
- Platelet activating factors
What causes enterocyte death in NEC?
- Imbalance in the pro and anti-inflammatory mediators
- Increased pro-apoptotic protease activity
Which part of the bowel is affected in NEC?
Any part of small or large bowel may be affected, but terminal ileum or sigmoid colon is usually involved
What are the risk factors for NEC?
- Prematurity
- Hypoxia-ischaemia to the bowel
- Feeding factors
- Infection
What is the main risk factor for NEC?
Prematurity
What are the prenatal causes of hypoxia-ischaemia to the bowel?
- IUGR
- Perinatal asphyxia
When in particular is IUGR a risk factor for NEC?
If absent or reversed end-diastolic flow of fetal arteries
What are the post-natal causes of hypoxia-ischaemia to the bowel?
- PDA
- Reduced blood flow
- Asphyxia
What can cause a reduced blood flow to the bowel in the post-natal period?
- Umbilical catheters
- Indomethacin
What are the feeding risk factors for NEC?
- Rapid increase in enteral feeds
- Formula milk
- Hypertonic formula
What are the infectious risk factors for NEC?
Bacteria in intestinal wall and/or blood stream
What is the role of anaemia in the development of NEC?
Proposed that it leads to compromise of the mesenteric blood flow causing intestinal hypoxia and mucosal injury
Does transfusion affect outcomes in NEC?
Can predispose to NEC
How can blood transfusion predispose to NEC?
Transfusion-related repercussion gut injury (TRAGI) of the hypoxaemic gut has been postulated to predispose anaemic preterm infants to NEC
Are probiotics helpful in NEC?
Benefit remains unproven
How is NEC managed?
- Stop feeds
- Large bore naso/orogastric tube for intestinal decompression
- Start broad spectrum antibiotics
- Provide supportive care
When might surgical intervention be required for NEC?
- Bowel perforation
- Failure of medical treatment
What are the surgical options for the management of NEC?
- Peritoneal drainage at the bedside
- Resection of non-viable bowel and anastomosis or ileostomy and colostomy
