012315 congenital defects of bowel

Question 1

esophageal atresia

Answer 1

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

Question 2

when should bilirubin begin to decrease in newborns?

Answer 2

by day 7

Question 3

when is jaundice abnormal in newborn?

Answer 3

beyond 2-3 weeks of age
direct bilirubin over 2
total bilirubin over 12 (term)
total bilirubin over 14 (preterm)

Question 4

what is a possible cause of direct hyperbilirubinemia in infant?

Answer 4

biliary atresia

Question 5

possible causes of neonatal bile duct obstruction

Answer 5

biliary atresia
choledochal cyst
others (rare)

Question 6

when does biliary atresia typically present?

Answer 6

4-6 wks

Question 7

what can biliary atresia cause in the end?

Answer 7

cirrhosis

Question 8

pathogenesis of biliary atresia

Answer 8

likely an in utero biliary epithelial injury leading to inflam
etiology unknown

Question 9

in biliary atresia, bile duct becomes

Answer 9

fibrotic

Question 10

choledochal cyst

Answer 10

dilatation of bile duct

Question 11

pathogenesis of choledochal cyst

Answer 11

• disordered organogenesis
• pancreaticobiliary malunion
• acquired weakness
• distal obstruction

Question 12

when does choledochal cyst usually present

Answer 12

over 1 year old (75%)

Question 13

bilious (any shade of yellow or green) emesis

Answer 13

surgical emergency

Question 14

developmental defect in malrotation

Answer 14

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

Question 15

diagnostic test for malrotation

Answer 15

upper GI test used to look for location of ligament of treitz (duodenojejunal jxn), which should be to L of spine

Question 16

double bubble

Answer 16

duodenal atresia

Question 17

Meckel’s diverticulum

Answer 17

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

Question 18

rule of 2’s for Meckel’s diverticulum

Answer 18

2 types of abnormal lining in it (stomach and pancreas)

usually symptomatic by 2 years of age

Question 19

symptoms of Meckel’s diverticulum

Answer 19

bleeding into the intestine
blockage of the intestine
inflammation

Question 20

massively dilated colon

Answer 20

Hischsprung’s disease

Question 21

Hirschsprung’s disease

Answer 21

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

Question 22

RET mutations

Answer 22

commonly occur in Hirschprung’s disease

RET is a tyrosine kinase that transduces growth for tissues including neural crest cells

Question 23

clinical presentation of Hirschprung’s dis

Answer 23

failure to pass meconium
functional obstruction/bilious emesis
enterocolitis (stasis of stool leading to bacterial overgrowth/sepsis)

Question 24

if feeding fine before but has problem now, think

Answer 24

necrotizing enterocolitis or

sepsis w/ ileus

Question 25

necrotizing entercolitis is most common in

Answer 25

premature infants

Question 26

pathophysiology of necrotizing enterocolitis

Answer 26

not well known

prematurity–possibly abnormal bacteria in gut
dysbiosis
formula feeding
impaired mucosal defense (b/c premature)

Question 27

end result of necrotizing enterocolitis

Answer 27

ischemia, necrosis, bacterial translocation into systemic circulation

Question 28

diagnosis of necrotizing enterocolitis

Answer 28

abdominal distension
feeding intolerance/emesis
rectal bleeding
abdominal wall erythema
temperature instability/apnea/bradycardia
penumatosis on XR (air in abdominal wall-implies there’s migration of bacteria)

Question 29

anorectal malformations

Answer 29

no opening or opening to wrong spot