Congenital Defects of the Bowel Flashcards Preview

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Flashcards in Congenital Defects of the Bowel Deck (43)
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1
Q

Describe the anatomy of the most common type of tracheo-esophageal atresia

A

85%:

  • upper esophagus ends in blind pouch,
  • lower esophagus attached to trachea
2
Q

Tracheoesophageal fistula:

associated with what other congenital anomalies?

A

20% assoc with VACTERL:

Vertebral

Anorectal

Cardiac

TEF

Renal

Limb

3
Q

Tracheoesophageal fistula

-clinical presentation for dx (4)

A
  1. prenatal polyhydramnios
  2. excessive salivation (‘mucousy’ baby)
  3. feeding intolerance
  4. failure to pass NG/OG tube
4
Q

Physiologic Jaundice in newborns

-why? mechanisms (3)

A
  1. decreased RBC half life of newborns
  2. Newborn liver has lower ability to conjugate bilirubin
  3. reduced enterohepatic circulation
5
Q

Neonatal Jaundice is abnormal when:

  1. jaundice lasts beyond ? age
  2. direct bilirubin >?
  3. (term) total bilirubin > ?
  4. (preterm) total bilirubin > ?
A
  1. beyond 2-3 weeks old
  2. >2mg/dL
  3. >12 mg/dL
  4. >14 mg/dL
6
Q

Neonatal Bile Duct obstruction

-what are the 2 main causes?

A
  1. BIliary atresia
  2. choledochal cyst
7
Q

Biliary atresia

  • when do babies typically present?
  • presenting symptoms (3)
A
  • typical presentation 4-6 weeks old
    1. Jaundice
    2. ahcolic, pale stool (no bile in gut)
    3. Dark urine (bilirubinemia)
8
Q

Biliary atresia

-what’s abnormal on blood test?

A

-conjugated hyperbilirubinemia

9
Q

Biliary atresia

  • describe natural progression of disease
  • life expectancy w/o tx
A
  1. Progressive obliteration of extrahepatic biliary sructures
  2. by 12 weeks–cholestasis, neocholangiogenesis, hepatocellular injury
  3. eventually: cirrhosis, portal HTN, end stage liver disease

Death <2 years old. Require Kasai procedure and/or transplanation

10
Q

Biliary atresia

  • etiology
  • genetic inheritance?
A
  • unknown, but likely an in utero biliary epithelial injury that leads to inflammation.
  • possible infectious and toxic stimuli
  • probably not genetic
11
Q

Biliary atresia

-what do you see on liver biopsy, and what’s happening?

A

Neocholangiogenesis (bile duct proliferation)

  • multiple bile ducts try to proliferate inside liver, but lack of bile ducts leading out of liver, so liver is damaged by bile back pressure.
  • use CK19 stain to visualize
  • eventually: cirrhosis (you see bridging fibrosis)
12
Q

Biliary atresia

  • describe surgical tx
  • Prognosis after surgery (3 groups)
A

Kasai procedure (hepatoportoenterostomy):

  1. Cut small intestine and attach distal end to liver at the porta hepatis (where the common hepatic duct emerges) to allow gut entry of bile
  2. Connect the remaining end of intestine back into distal intestine (forming a ‘Y’)

Prognosis:

1/3 good long term result

1/3 progressiv liver disease

1/3 short term failure (need liver transplant)

13
Q

Biliary atresia

-give what to patients after Kasai procedure? (3)

A
  1. DEAK vitamin supplementation (malabsorption of fat soluble)
  2. ursodexycholic acid
  3. ampicillin prophylaxis for cholangitis
14
Q

Jaundiced infant, with elevated direct bilirubin.

what’s your differential? (3)

A
  1. cholelithiasis/choledocholithiasis
  2. bile plug syndrome
  3. choledochal cyst

other unlikely: infection, tumors

15
Q

Choledochal cysts

-what congenital anatomic variant is much more common in people with a choledochal cyst, and why?

A

-Long common channel for common bile duct and pancreatic duct.

A distal blockage can lead to pancreatic enzymes flowing up the common bile duct and causing cyst formation.

16
Q

Choledochal cysts

-most feared complication

A

-Biliary adenocarcinoma (2.5-15% incidence)

17
Q

Choledochal cysts

  • most common symptoms for pts >1 year old: (3)
  • late complications
A
  1. pain
  2. intermittent jaundice
  3. mass
  4. cirrhosis, portal HTN
  5. biliary adenocarcinoma
18
Q

Choledochal cysts

  1. best test to dx
  2. most common tx
A
  1. Ultrasound
  2. Remove bile duct/cyst, attach intestine directly to liver

(hepaticojejunostomy, hepaticoduodenostomy)

19
Q

You see an infant vomiting yellow/green material.

Think what?

A

Bilious emesis is a surgical emergency!

20
Q

Malrotation of gut:

-what is the normal embryologic process, and what happens with malrotation?

A
  1. normal: GI tract rotates 270 degrees counterclockwise
  2. malrotation: Gut twists on itself, causing volvulus–lack of mesenteric blood flow means twisted gut segment can die
21
Q

What are Ladd bands, and what’s their danger?

A

Ladd bands: fibrous peritoneal tissue that connects cecum to abdominal wall.

In malrotation, Ladd bands cross the duodenum and can cause duodenal obstruction

22
Q

Malrotation of gut:

  • How to dx?
  • describe surgical tx
A

Imaging: use Xray with barium swallow.

If ligament of Treitz (duodenojejunal junction) is right of spine, suspect malrotation

-Ladd’s procedure: untwist bowel, cut Ladd’s bands

23
Q

Duodenal atresia

clinical presentation (3)

A
  1. polyhydramnios in utero (no swallowing of amniotic fluid)
  2. ‘double bubble’ sign
  3. bilious vomiting
24
Q

Duodenal atresia

-assoc with what other congenital problem(s)?

A
  • Down’s syndrome
  • also other cardiac, genitourinary, anorectal abnormalities
25
Q

Jejunoileal Atresia

  • pathogenesis
  • what are 2 possible causes?
A
  • in utero vascular disruption leads to ischemic necrosis of fetal intestine. Gaps in intestine result.
    1. Inherited thrombophilia–spontaneous clots may cause ischemia to gut
    2. maternal use of vasoconstrictive meds–eg pseudoephedrine, cocaine, nicotine
26
Q

Duodenal atresia:

  • pathogenesis
  • during what weeks?
A
  • In utero, duodenaum passes through a solid phase, then lumen opens during weeks 8-10
  • insult during that time can result in duodenal atresia
27
Q

Meckel’s diverticulum

-is this a ‘true’ diverticulum? why?

A
  • Yes, b/c it contains all 4 layers of the bowel wall:
    1. mucosa
    2. submucosa
    3. muscularis propria
    4. serosa
28
Q

Meckel’s diverticulum

-pathogenesis

A

-failure of the vitelline duct to involute. Vitelline duct connects GI lumen with yolk sac in utero

29
Q

Meckel’s diverticulum

-rule of 2’s (5)

A
  1. occurs in 2% of population
  2. 2 types of abnormal lining (stomach and pancreas)
  3. located within 2 feet of ileocecal valve
  4. 2 inches in length
  5. symptoms by age 2
30
Q

Meckel’s diverticulum

-symptoms: (3)

A
  1. bleeding
  2. blockage of intestine
  3. inflammation

most cases are asymptomatic

31
Q

Hirschsprung’s disease

  • pathogenesis
  • associated with what congential problem(s)?
A
  • failure of neural crest cells to migrate to colon wall to form enteric nervous system. The segment of colon w/o neural cells lacks both Meissner’s and Auerbac’s plexuses.
  • Loss of motility at the junction between normal and aganglionic segments.
  • assoc with Down’s syndrome
32
Q

Hirschsprung’s disease

-specific genetic mutation

A

RET mutations are most common.

RET is a receptor tyrosine kinase that transduces growth/differentation signals.

33
Q

Hirschsprung’s disease

-what invasive test to dx?

A

Suction Rectal biopsy

-special biopsy that takes all layers of gut wall to search for ganglion cells

34
Q

Hirschsprung’s disease

-clinical presentation (3)

A

typically newborn:

  1. failure to pass meconium
  2. bilious emesis
  3. enterocolitis (life threatening)
35
Q

Necrotizing enterocolitis

  • classic presentation
  • classic population
A

-classically a premature infant presents a few weeks after birth with abdominal distention and increased difficulty breathing

36
Q

Necrotizing enterocolitis

-what are 3 significant factors in its pathogenesis?

A
  1. prematurity
  2. dysbiosis (alteration of normal gut flora)
  3. formula feeding (you should feed infant human milk)
37
Q

Necrotizing enterocolitis

-clinical presentation (6)

A
  1. abdominal distention
  2. feeding intolerance/emesis
  3. rectal bleeding
  4. abdominal wall erythema
  5. temp instability/apnea/bradycardia
  6. pneumatosis on xray (gas cysts in bowel wall)
38
Q

Necrotizing enterocolitis

-list stages of disease and their characteristic symptoms

A

Stage 1: feeding intolerance

Stage 2: pneumatosis intestinalis (gas cysts in colon wall)

Stage 3: ascites, perforation, peritonitis

39
Q

Necrotizing enterocolitis

  • mortality rate
  • after tx, there is increased risk of what? (3)
A
  • mortality 20-30%
  • Increased risk of:
    1. short gut syndrome (after removing bowel)
    2. neurodevelopmental delay
    3. bronchopulmonary dysplasia
40
Q

Anorectal malformation

-associated with what congenital disorders? (2)

A
  1. Down’s
  2. VACTERL complex

vertebral, anorectal, cardiac, TEF, renal, limb

41
Q

VACTERL association

A

vertebral

anorectal

cardiac

TEF

esophageal atresia

renal

limb

42
Q

Anorectal malformation

  • pathogenesis
  • how do males and females typically present differently?
A
  • abnormal descent of urorectum–hindgut fails to descend to anus.
  • males: more common “high” malformations–rectovesicular or rectourethral fistulas
  • females: more common “low” malformations to perineum/vestibule. Or anteriorly displaced anus
43
Q

Anorectal malformation

-symptoms after surgical treatment

A

100% will have periodic constipation. Anorectal region is missing the nerves that make rectum relax in response to rectal distention.