Neonatal period

Up to 44 weeks post conception

Prenatal
- Previous pregnancies (complications and outcomes)
- Maternal gestational ilnesses (GDM, pre-eclampsia)
- Screening USS
- Other prenatal Ix (maternal AFP, bhcg, oestrogen, chorionic villous sampling, amniocentesis)
Perinatal
- Weeks of gestation
- Induced vs spontaneous
- Complications
- APGAR
Neonatal
- Complications
- Infections
- Feeding (initiation, type, rate achieved)
- Passage of meconium within first 24 hours
FHx
- Maternal and paternal health
- Previous congenital abnormalities
- CF
- Consanguinity

Intestinal obstruction

Most common abdominal emergency in the neonatal period
Usually due to a congenital, developmental or genetic abnormality
History
- Symptoms
  - Vomiting especially bilious (green)
  - Distension
Assessment
- Vital signs
- Dysmorphic features
- Abdo - remember to check for inguinal herniae
- Check anus
Investigation
- Bloods can help to assess level of dehydration and sepsis
- AXR is basic test
  - Double-bubble = duodenal obstruction. Can also occur with stenosis, duodenal web, or malrotation.
  - Multiple dilated loops = more distant obstruction
  - Impossible to differentiate SBO from LBO in neonates on AXR
- Contrast study is often required
  - WSC should always be used instead of barium (more effective in releasing meconium ileus)
  - Indications
    - Suspected malrotation - upper GI contrast study
    - Suspected distal pathology - contrast enema
      - Will help differentiate meconium ileus, jujeuno-ileal atresia and Hirschsprung disease
    - Meconium ileus - microcolon, dilated proximal small bowel and a soap-bubble appearance in RLQ. Bubbly appearance is due to gas mixing with viscous meconium.
    - Ileal atresia - microcolon, contrast entering the distal small bowel but dilated proximal small bowel without contrast
    - Hirschsprung disease - lateral film with contracted distal rectum with dilated bowel proximally
Initial management
- 8-10Fr NGT
- Transfer to paeds surg
Specific conditions
- Oesophageal atresia
  - Gap in oesophagus = blind-ending oesophageal pouch
  - 90% of cases have a connection to trachea (TOF)
  - Signs:
    - Difficulty swallowing saliva, coughing or resp distress during first feed
    - Inability to pass NGT (leave it in oesophageal pouch on continuous suction)
  - Repair by paeds surg
  - Often have cardiac conditions too
- Meconium ileus
  - Mostly occurs in children with CF - all patients will need workup (sweat chloride and genetic studies)
  - Meconium becomes sticky and causes obstruction
  - Can lead to complications - volvulus, atresia, perforation
  - Resuscitation, NGT, WSC enema
  - WSC relieves obstruction in 50% of cases. This can be repeated if progress is made but obstruction persists.
  - If unsuccessful, a laparotomy must be done. In absence of volvulus or perforation, enterotomies are made and mechanical washout is performed. Otherwise may need resection if there are complications, and can also require a stoma.
- Intestinal atresia/stenosis
  - Can occur at any point in GIT
  - Confirm diagnosis with either upper or lower contrast studies
  - If distal obstruction, will need contrast enema to exclude Hirschsprung or meconium ileus.
  - Generally stable once decompressed and resuscitated.
  - Mostly treated with primary anastomosis.
- Hirschsprung disease
  - Congenital lack of ganglion cells in distal bowel. Results in failure of peristalsis and functional obstruction.
  - 2-5% will have MEN2A
  - Transition zone is usually rectosigmoid, but can affect entire colon and rarely small bowel.
  - Can present later with a history of severe constipation
  - Gold standard is rectal biopsy, which could sometimes be done with suction technique at bedside
  - Initial management is DRE stimulation, NGT, and rectal irrigation with normal saline (10ml/kg)
  - Current standard of care is primary reconstructive surgery without colostomy for most patients
  - Complications are severe enterocolitis and colonic perforation
- Anorectal malformations
  - Low - rectoperineal or rectovestibular fistulas in female patients
  - High - fistula from rectum to bladder neck in a male, or a cloaca in a female
- Malrotation
  - Non-rotation occurs when rotation fails to occur between 6 and 10 weeks of gestation - end up with wide-based mesentery, which does not require correction.
  - If the process is interrupted partway through, leaving caecum and ligament of Treitz close together, which can result in a narrow-based mesentery. The bowel will then be prone to midgut volvulus around SMA and SMV which can lead to ischaemia - true surgical emergency. Colon and caecum on left.
  - Volvulus is a complication of malrotation, and is most common in first week of life
  - The most common presentation of malrotation is bilious vomiting, for one of two reasons:
    - Midgut volvulus
    - Compression of duodenum by Ladd's bands
  - Every neonate presenting with bilious vomiting should be considered to have midgut volvulus until proven otherwise.
  - Upper GI contrast study is the preferred study
    - Abnormal position of DJ flexure
    - Spiral, corkscrew or Z shaped course of the distal duodenum and proximal jejunum
    - Location of the proximal jejunum in the right abdomen
  - Abdominal USS may show whirlpool sign in SMA
  - Needs laparotomy - untwist, check for viability, only resect grossly necrotic bowel. Consider palliation for children with necrosis of the entire midgut.
    - Ladd procedure if intestine is viable:
      - Division of Ladd's bands
      - Mobilisation of colon to left side of abdomen
      - Mobilisation and straightening of duodenum
      - Dissection and widening of small bowel mesentery
      - Appendicectomy

Inflammatory conditions

(note that peritonitis is difficult to detect in neonates)

Meconium peritonitis
Necrotising enterocolitis
- Preterm or small for age infants
- Combination of bacterial colonisation, intraluminal substrate and intestinal ischaemia/hypoxia
- Suspect with sepsis, increased abdominal girth, feeding intolerance, abdominal wall discolouration, bloody stools
- AXR - pneumatosis intestinalis, PV gas, free air
- USS - pneumatosis, free fluid, intestinal hypoperfusion and hypomotility
- Initially - bowel rest, NGT, abx, TPN
- If persistent deterioration and signs of necrosis or perforation - OT
  - Bedside peritoneal drainage
  - Laparotomy with resection of grossly necrotic bowel and either primary anastomosis or stoma
Isolated ileal perforation
- Preterm or small for age infants
- Generally focal disease causing perforation
- Sudden deterioration, sepsis, free air without pneumatosis on AXR
- Treat similar to NEC

Other conditions

Incarcerated inguinal hernia
- See separate topic
Abdominal wall defects
- Gastroschisis - defect to right of umbilicus, through which most of the intestinal tract protrudes
  - See 'umbilical hernia'
- Omphalocoele (exemphalos) is herniation of bowel +/- solid organs into umbilical cord, and is often a/w other abnormalities
  - See 'umbilical hernia'
- Resuscitation and NGT
- Bowel or sac wrapped in warm saline soaked sterile gauze and covered with sterile plastic wrap
- Repaired, often primary closure, sometimes staged
Patent omphalomesenteric duct
- ECF between bowel and umbilicus - meconium and mucus at umbilicus within first few days of life. Need laparotomy and excision of fistula tract.
- Umbilical polyp - caused by persistent distal duct. Resembles umbilical granulomas, except it does not improve with silver nitrate cauterisation. Need to excise mucosal remnant and underlying sinus.
Persistent allantois
- Persistent urachus may result in the formation of a vesicocutaneous fistula (urine at umbilicus), extra-peritoneal urachal cyst (lower abdominal mass), or a urachal sinus (drainage of mucus)
- Treat by excision of urachal remnant with closure of bladder as necessary