Neonatal intestinal obstruction

General information Neonatal intestinal obstruction can be due to a variety of causes Presenting clinical features are often similar Bile-stained vomiting is never normal in a neonate and implies obstruction 95% of babies pass meconium within the first 24 hours of life Failure to pass meconium is also a feature of obstruction The degree of abdominal distension is variable

Clinical Features Triad of : Vomiting, abdominal distension, and failure to pass meconium (constipation) Manifestation depends on the site of obstruction

Principles of Management GIT decompression fluid and electrolyte management Surgical treatment accordingly

Diagnosis Antenatal U/S, MRI Plain X-Ray upright, and supine (Air fluid level) Contrast material

Causes of Neonatal Intestinal obstructions Atresias – duodenal, jejunal, colonic Meconium ileus; Meconium plug Hirschsprung’s disease Imperforate anus Malrotation with volvulus

Duodenal atresia Occurs in 1 in 5-6,000 live births Site of obstruction is most commonly in 2nd part of duodenum Proximal duodenum become hypertrophied 50% are associated with polyhydramnios 60% of such pregnancies are complicated or end prematurely Can often be diagnosed with antenatal ultrasound

Duodenal atresia 30% of babies with duodenal atresia have Down's syndrome Other associated abnormalities are cardiac anomalies, malrotation and biliary atresia Postnatally presents with bilious or non-bile stained vomiting X-ray may show a 'double-bubble' and no gas within the bowel distally

Management A nasogastric tube should be passed Intravenous fluid resuscitation should be given Major cardiac and other defects should be excluded Duodenoduodenostomy should be performed when resuscitated

Other atresias Atresias of the small bowel and colon are less common Often associated with polyhydramnios Bilious vomiting and distension are key features x-ray will show dilated bowel and a gas-free rectum A nasogastric tube should be passed Intravenous fluid resuscitation should be given At operation, dilated proximal bowel should be resected or tapered A primary anastomosis may be possible

Types (Bowel loss, mesentery) web (membrane), normal length, normal mesentery. Type 2 fibrous cord between blind ends of the atretic bowel but have an intact mesentery. Type 3/A There is a complete separation of the blind ends of the separated bowel by a v-shaped mesenteric defect. Type 3/B Apple peal or Christmas tree deformity. Type 4 Multiple atresia, string of sausage or string of beads.

Type 1 Type 2 Type 3/A Type 3/B Type 4

Type I Atresia

Type IV Atresia

Annular pancreas

Meconium ileus Commonest cause of neonatal intraluminal intestinal obstruction 80% cases are associated with cystic fibrosis Cystic fibrosis occurs in 1 in 2000 live births Inherited as an autosomal recessive trait Viscid pancreatic secretions cause autodigestion of pancreatic acinar cells Resulting meconium is abnormal and putty-like in consistency

Meconium ileus Meconium becomes inspissated in the lower ileum There is a microcolon Presents with bilious vomiting and distension usually on first day of life Passage of meconium is delayed Meconium filled loops of bowel may be palpable X-ray may show a 'ground-glass' appearance, especially in the right upper quadrant

Meconium Ileus (cont) Diagnosis made with contrast enema Gastrograffin enema with aggressive hydration can be used to treat some Operative evacuation of meconium May require ostomy Proximal bowel dilated and distal bowel may be very small (microcolon) and require time to dilate with use

Management Gastrografin enemas may be successful in 50% of patients If unsuccessful, surgery will be required Limited resection and stomas may be required

Meconium plug Difference between meconium ileus and meconium plug is site and severity of obstruction Preterm infants, infants of diabetic mothers, IUGR babies, otherwise ill babies Treatment with glycerin suppositories and warm saline enemas May require contrast enema to make diagnosis Normal stooling pattern should follow evacuation of plug

Malrotation Volvulus

Malrotation Between 4 and 10 weeks of development intestines herniate into umbilical cord When returned to abdomen they rotate 270 degrees anticlockwise As a result Duodeno-jejunal flexure lies to the left of the midline

Malrotation Caecum lies in right iliac fossa Transverse colon lies anterior to the small bowel mesentery Partial failure of rotation results in malrotation Commonest abnormality results in caecum lying close to DJ flexure

Malrotation Resulting midgut mesentery is abnormally narrow and liable to volvulus Fibrous bands may be present between caecum and DJ flexure (Ladd's bands) Radiological investigations are often unhelpful

Clinical presentations Three clinical presentations Presents late with intermittent bile stained vomiting and distension Presents early with collapse and acidosis due to intestinal infarction Presents as incidental finding on radiological investigation

Malrotation & Volvulus (Volvulus Neonatorum) 90% occur first month Bilious emesis Abdominal distention, peritonitis Septic shock Rectal bleeding Absolute surgical emergency; detorsion, Ladd procedure, possible bowel resection

Malrotation with volvulus Can occur in the fetus – large calcified shadow in midabdomen on x-ray Sudden onset of bilious emesis in infant – requires rule out Signs of shock and sepsis can be present Surgical emergency since intestinal viability is at stake. UGI to evaluate for position of ligament of Treitz

Management After resuscitation, early laparotomy may be required Any volvulus should be reduced Resection may be required if there has been small bowel infarction Any Ladd's bands should be divided The base of the mesentery should be widened Colon should be placed on the left of the abdomen Small bowel should be placed on the right Inversion appendectomy should be performed to prevent future diagnostic uncertainty