Necrotising enterocolitis

Question 1

Necrotising enterocolitis - background

Answer 1

1. Def = serious illness with bacterial invasion of ischaemic bowel wall; mainly affects preterm infants in first few weeks of life
2. Epi = most common neonatal surgical emergency; incidence 1-3/1000 live births.
3. Incidence 6x reduced in preterm infants fed breast milk
4. Disease may involve an isolated area of gut, or be extensive. Distal terminal ileum and proximal colon most frequently affected. Multi-organ failure associated with diffuse disease
5. Cause = multifactorial. Severe intestinal necrosis is the end result of an exaggerated immune response within the immature bowel leading to inflammation and tissue injury

Question 2

NEC - risk factors

Answer 2

1. Prematurity
2. IUGR (causes chronic bowel ischaemia)
3. Hypoxia
4. Polycythaemia
5. Hyperosmolar milk feeds

Question 3

NEC - presentation

Answer 3

Early

1. Most common in second week after birth
2. Non-specific illness
3. Vomiting/bilious aspirate from gastric tube
4. Poor feed toleration (increasing gastric aspirates)
5. Abdominal distension

Late

1. Additional abdominal tenderness
2. Blood, mucus or tissue in stools
3. Bowel perforation
4. Shock
5. DIC, multi-organ failure

Question 4

NEC - ix

Answer 4

1. Bloods (5) FBE, UEC, blood cultures, coagulation screen, group and hold + cross-match
2. VBG
3. AXR (early = abnormal gas pattern with dilated loops of bowel that is consistent with ileus; late = pneumatosis intestinalis [bubbles of gas in small bowel wall])
   +/- the following:
4. Fecal occult blood
5. Abdominal U/S

Question 5

NEC - mx

Answer 5

1. Stop milk feeds for 10-14d
2. Insert gastric tube on free drainage
3. Systemic support = assisted ventilation, correct BP and DIC, parenteral nutrition
4. IV antibiotics for 10-14d (e.g. benzylpenicillin + gentamicin + metronidazole [UK])
5. Surgery if GI perforation, GI obstruction or deterioration despite medical tx
   - If localised disease, surgical resection of involved bowel with primary repair
   - If more extensive, two-stage repair + bowel resection + enterostomy (i.e. stoma creation), followed by later intestinal reanastomosis)

Question 6

NEC - prognosis (3)

Answer 6

1. Overall mortality 22%, increased mortality if VLBW, extensive intestine involvement/multi-organ failure, intrahepatic portal gas (accumulation of gas in the portal vein and its branches)
2. Extensive bowel resection may result in short bowel syndrome
3. Excellent prognosis in those who respond to medical tx, but subsequent stricture may develop

Question 7

Short bowel syndrome - overview

Answer 7

1. Malabsorption disorder resulting from extensive small bowel resection
2. Common causes in children = NEC, intestinal atresia, midgut volvulus, gastroschisis
3. Clinical effects = diarrhoea, fluid/electrolyte disturbances, malabsorption of nutrients
4. With appropriate mx, reasonable QoL. Mx (5) = nutritional support (PN after significant bowel resection), dietary modification + referral to dietitian, antidiarrhoeal drugs, vitamin and mineral supplementation, oral fluid replacement
5. Minority require long-term parenteral nutrition with supervision by specialist team, +/- intestinal transplantation