012315 congenital defects of bowel Flashcards
esophageal atresia
the esophagus has a dead end
can have fistulas to the trachea
more than 50% association w other major congenital anomalies (VACTERL)–vertebral, anorectal, cardiac, tracheoesophageal fistula, renal, limb
when should bilirubin begin to decrease in newborns?
by day 7
when is jaundice abnormal in newborn?
beyond 2-3 weeks of age
direct bilirubin over 2
total bilirubin over 12 (term)
total bilirubin over 14 (preterm)
what is a possible cause of direct hyperbilirubinemia in infant?
biliary atresia
possible causes of neonatal bile duct obstruction
biliary atresia
choledochal cyst
others (rare)
when does biliary atresia typically present?
4-6 wks
what can biliary atresia cause in the end?
cirrhosis
pathogenesis of biliary atresia
likely an in utero biliary epithelial injury leading to inflam
etiology unknown
in biliary atresia, bile duct becomes
fibrotic
choledochal cyst
dilatation of bile duct
pathogenesis of choledochal cyst
- disordered organogenesis
- pancreaticobiliary malunion
- acquired weakness
- distal obstruction
when does choledochal cyst usually present
over 1 year old (75%)
bilious (any shade of yellow or green) emesis
surgical emergency
developmental defect in malrotation
narrow mesenteric base permits abnorma mobility of the small bowel, allowing the mesentery to twist (midgut volvulus and entire midgut can die)
Ladd’s bands (attach cecum to abd wall), which cross the duodenum, can lead to obstruction
diagnostic test for malrotation
upper GI test used to look for location of ligament of treitz (duodenojejunal jxn), which should be to L of spine
double bubble
duodenal atresia
Meckel’s diverticulum
TRUE diverticulum of the small bowel
results from failure of involution of the vitelline duct, the embryologic connection btwn lumen of the deveoping intestine and the yolk sac
rule of 2’s for Meckel’s diverticulum
2 types of abnormal lining in it (stomach and pancreas)
usually symptomatic by 2 years of age
symptoms of Meckel’s diverticulum
bleeding into the intestine
blockage of the intestine
inflammation
massively dilated colon
Hischsprung’s disease
Hirschsprung’s disease
congenital defect in intestinal innervation
can be associated w Trisomy 21
normal migration of neural crest cells from small intestine is disrupted, so a segment of distal colon exists w/o nerve cells (both Meissner and Auerbach’s)
most common in rectosigmoid, but can be entire colon
RET mutations
commonly occur in Hirschprung’s disease
RET is a tyrosine kinase that transduces growth for tissues including neural crest cells
clinical presentation of Hirschprung’s dis
failure to pass meconium
functional obstruction/bilious emesis
enterocolitis (stasis of stool leading to bacterial overgrowth/sepsis)
if feeding fine before but has problem now, think
necrotizing enterocolitis or
sepsis w/ ileus
