Flashcards in 26. Congenital defects of the bowel Deck (44):
What is the key presentation that can indicate malrotation (medical emergency)?
Bilious emesis (yellow/green)
When in devo does the gut extend out of the abdomen, and how does it rotate?
Twists 90 degrees CCW while hernitated, and an additional 180 decrees CCW when back in the abdomen
What fixes the SI at the duodenal jejunum?
Ligament of Treitz
What are bands that cross the duodenum and can cause obstruction with midgut volvulus?
What will be seen on abdominal x-ray with an NGT in when there is midgut volvulus?
Where should the ligament of Treitz be located on abdominal X-ray?
To the left of the patient's spine at the duodenojejunal junction
What is the Ladd's procedure?
Treatment for midgut volvulus
- untwisting of the bowel, removal of the Ladd's bands, widening of the mesentery
- Put the small bowel on the right and colon on the left
- Appendectomy to prevent future confusion with appendicitis
What is the classic sign for duodenal atresia on a prenatal US?
Double bubble sign, polyhydraminos
What is the pathogenesis of duodenal atresia?
Failure of recanalization--duodenum passes though solid phase but should have reopening of the lumen between weeks 8 and 10
Embryological insult during the recanalization period (weeks 8-10) can result in: (3)
1. Duodenal stenosis
2. Duodenal web
3. Duodenal atresia
What causes the double bubble sign?
Dilated stomach and proximal duodenum resulting from obstruction
What are the two things that should indicate duodenal atresia within a few hours of birth?
Vomiting that is clear or bilious
Double bubble sign on X-ray
What are the two possibilities for level of obstruction with duodenal atresia and which one is more common?
Pre or post-ampullary
80% are post-ampullary, resulting in bilious emesis
What genetic defects/congenital abnormalities is duodenal atresia associated with?
Trisomy 21 ***
What are the steps for tx of duodenal atresia?
R/o other causes with physical exam and echo
Duodenoduodenostomy: anastomosis of proximal to distal duodenum
What is the pathogenesis of jejunoileal atresia?
In utero vascular disruption leads to ischemic necrosis of the fetal intestine
Necrotic intestine is reabsorbed, leaving blind proximal and distal ends, often with a gap in the mesentery
What are risk factors for development of jejunoileal atresia?
- Inherited thrombophilia leading to spontaneous thormbosis
- Maternal use of vasoconstrictive medications may disrupt the mesenteric blood flow: pseudoephedrine, cocaine, and nicotine
- Rare familial inheritance
What causes the low birth weight and prematurity in jejunoileal atresia?
Congenital anomalies associated with jejunoileal atresia?
Unlike duodenal atresia, not commonly associated with extraintestinal anomalies
Treatment of jejunoileal atresia
Surgery: explartory lapartomy, primary anastomosis
**long term issues depending on the intestinal length
What can be used for a child that is hard to get an IV in?
IO line (intraosseous)
What is a congenital disease in intestinal inntervation? More common in what gender?
Hischsprung's disease is associated with what congenital disorder?
Trisomy 21 (downs syndrome)
What is the MC genetic mutation to be associated with Hirschsprung's disease?
RET mutations: RET is a receptor tyrosine kinase that transduces differentiation signals in many developing tissues, including neural crest cells
What is the pathogenesis of Hirschsprung's disease?
Normal migration of neural crest cells from the SI to the cecum is disrupted (usually serves to establish the enteric nervous system)
**leads to loss of both the Meissner/submucosal and Auerback/myenteric plexus, or aganglionosis
What happens in the aganglionated segment of the bowel in Hirschsrung's disease?
Peristalsis is absent and results in a functional obstruction
Where is the most common location to have Hirschprung's disease?
What is the clinical presentation of Hirschsrung's disease in the newborn period?
1. Failure to pass meconium within 24 hr
2. Functional obstruction and bilious emesis
What is enterocolitis?
Who is more likely to get enterocolitis?
Life threatening complication of bacterial overgrowth, leads to sepsis
More common in patients with Down syndrome
What is the tx for Hirschsprung's disease?
Surgical resection of the aganglionated segment
Anastomosis of the normal colon to the rectum
Who gets necrotizing enterocolitis
**occurs in 10% of infants that weigh <1,500 gm at birth
**infrequent in term infants
What are two things that are protective against necrotizing enterocolitis?
What characteristics are used for the diagnosis of necrotizing enterocolitis?
Feeding intolerance and emesis
Rectal bleeding (inflammation of the mucosa)
Abdominal wall erythema
Pneumatosis on Xray
What is pneumatosis (seen with necrotizing enterocolitis?
Gas within the bowel wall
Occurs as a result of gas produced by bacteria within the serosal and muscularis layers of the bowel
What are risk factors for necrotizing enterocolitis?
Microbial bowel overgrowth
impaired mucosal defense
Circulatory instability of the intestinal tract
Medications that cause intestinal mucosal injury or enhance microbial overgrowth
What are the components of tx of necrotizing enterocolitis?
Broad spectrum antibiotics: ampicillin, gentamycin, ceftriaxone, metronidazole
Bowel rest: NPO, TPN
What are the indications for surgery with necrotizing enterocolitis?
- Pneumoperitoneum--> free air
- Clinical deterioration
- Discolored abdomen, fixed loop, and obstruction
What will be seen on histology with necrotizing enterocolitis?
Epithelial layer is absent, villi are necrotic, hemorrhage and some inflammation
What are the two genetic anomalies that anorectal malformations are associated with?
What is VACTERL complex
Limb anomalies (radius)
What happens in anorectal malformations?
Abnormality of caudal descent of the urorectum: failure of descent of the hindgut to anus or the fusion of urorectal ridges to the walls of the cloaca
The antorectal malformations in males are most often ___ with rectovesicular or rectourethral fistula
Females have ___ malformations to the perineum or vestibule
What is important in evaluation of a patient with anorectal malformation?
Get ECHO, renal US, do good physical exam