Gastroenterology

Question 1

Most common complication medical NEC

Answer 1

strictures

Question 2

Reducing volvulus = Ladd’s procedure

Answer 2

turn bowel COUNTERCLOCKWISE. remove appendix, separate Ladd’s bands that connect intestine to mesentery, situate bowel in abdomen with cecum in LLQ, duodenum on R

Question 3

Risk factors for NEC

Answer 3

indomethacin, postnatal steroids, vasopressors, mechanical ventilation / surfactant, maternal chorio

Question 4

Gastroschisis risk factors

Answer 4

YOUNG maternal age, smoking, alcohol, illicit substance use, OTC vasoactive meds, salicylates

Question 5

Gastroschisis concurrent anomalies?
Genetic causes?

Answer 5

10% have GI anomalies (intestinal atresia/stenosis). IUGR affects 20-60%.
Gene polymorphisms of endothelial nitric oxide synthase, intracellular adhesion molecule 1, atrial natriuretic peptide

Question 6

Omphalocele associate anomalies

Answer 6

50% have cardiac, urogenital, brain, spina bifida

Question 7

OEIS syndrome

Answer 7

omphalocele, cloacal exstrophy, imperforate anus, spinal defects

Question 8

Syndromes associated with omphalocele

Answer 8

T13, 18, Beckwith Wiedemann. OEIS

Question 9

Recurrence risk of neonatal hemochromatosis in subsequent pregnancies?

Answer 9

90%. Giving IVIG at 18 weeks significantly decreases risk

Question 10

Gastric pH is increased in neonates due to ______

Answer 10

decreased HCl secretion

Question 11

Polyhydramnios occurs in ______ of fetuses with jejunal atresia. Is less common in fetuses with ileal atresia

Answer 11

1/3

Question 12

What atresias are more common (in decreasing order)

Answer 12

Distal ileum > proximal jejunum > distal jejunum > proximal ileum

Question 13

Schwachman Diamond Syndrome (genetic)

Answer 13

rare AR d/o (1 in 75k)
90% of cases associated with mutation on chromosome 7q11
Important role in maturation of 60s ribosomal subunit and ribosomal assembly

Question 14

Schwachen Diamond clinical presentation

Answer 14

infancy - BM failure (neutropenia, anemia, thrombocytopenia), pancreatic dysfunction, recurrent infections, skeletal abnormalities. Neutropenia is most common hematologic abnormality. Increased risk of myelodysplastic syndrome and leukemia

Question 15

Pathophysiology of biliary atresia?

Answer 15

viral triggered immune reactions during development

Question 16

Meconium plug is due to _____?

Answer 16

functional immaturity and hypo-motility of COLON - immaturity of myenteric plexus nerve cells (meconium ILEUS involves distal ileum).

Question 17

Barrier defenses of GI system?

Answer 17

adaptive and innate
Secretory IgA, intestinal mucins, antimicrobial peptides, pathogen recognition receptors, immune cells

Question 18

Heme oxygenase converts _____

Answer 18

heme –> biliverdin
Biliverdin reductase converts biliverdin to bilirubin

Question 19

Neonatal hemochromatosis

Answer 19

iron deposited in liver and other tissues –> stillbirth. Causes IUGR, preterm birth. Liver failure, cardiac impairment. Normal/elevated LFTs, low fibrinogen, anemia, thrombocytopenia, high ferritin

Question 20

HLH

Answer 20

abnormally hyper-activated T-cells and macrophages. But also have neutropenia and low natural killer cell counts.

Dx: finding hemophagocytosis in samples of bone marrow, spleen, or lymph node

Question 21

When does gastric acid production reach adult levels? What are they at birth?

Answer 21

3 months of age
Birth: gastric pH is neutral to alkaline (alkaline amniotic fluid)

Question 22

Benefit of medium chain fatty acids?

Answer 22

can directly enter portal venous system from enterocyte

Question 23

Microcolon associations?

Answer 23

IDM, maternal hypothyroidism, maternal toxemia, prematurity

Question 24

Esophageal duplication cyst complication?

Answer 24

can become malignant in future

Question 25

Omphalocele (risk factors)

Answer 25

ADVANCED maternal age, 30% have abnormal karyotype (T13, 18, 21). 50-70% of affected patients have associated congenital anomalies, 10% B-W syndrome (omphalocele, gigantism, macro glossia, hypoglycemia 2/2 pancreatic hyperplasia)

Question 26

Omphalocele genetic causes

Answer 26

pituitary hemobox 2, insulin-like growth factor 2, cyclin-dependent kinase inhibitor 1C, methylenetetrahydrofolate reductase gene polymorphism (677C-T)

Question 27

Most common complication of Hirschsprung’s disease

Answer 27

acute bacterial enterocolitis

Question 28

Causes of duodenal vs jejunal / ileal atresias

Answer 28

Duodenal: failure to re-canalize during 8-10 weeks gestation (obliterated during 6-7 weeks)
Jejunal/ileal: vascular accident

Question 29

MCC abdominal flank mass

Answer 29

hydronephrosis

Question 30

Meconium plug syndrome risk factors

Answer 30

IDM, mag sulfate, CF

Question 31

Innate immune system in GI tract

Answer 31

Intestinal mucins: secreted by goblet cells, thick physical bacteria
Secretory IgA: binds to bacteria, prevent from penetrating epithelial layer
Antimicrobial peptides: produced by Paneth cells, but also goblet and epithelial cells
Pathogen recognition receptors: on surface or in cytoplasm of epithelial cells
Immune cells: dendritic, macrophages, NK cells, NK T- cells, gamma- T cells

Question 32

Cellular risk factors for NEC

Answer 32

NEC risk factors
Loose tight junctions
Thin goblet cell secretions
Few paneth cells (for antimicrobial peptides), decreased IgA, increased inflammatory cytokines, altered TLR4 signaling

Question 33

HLH cell difference compared to hemochromatosis

Answer 33

HLH has NEUTROPENIA and low natural killer cell counts (compared to neonatal hemochromatosis)