Peds GI Disease

Question 1

Understand the anatomic features and pathogenesis of Tracheo-esophageal fistula

Answer 1

Connection between distal esophagus and trachea. Proximal esophagus ends in blind pouch. Presents with choking with feeds and inability to swallow oral secretions. Can result in aspirations/infection

Pathogenesis: Failure of normal separation of intestinal and respiratory tracts (usually have esophageal atresia)

Prenatal – Polyhydramnios (because fetus cannot swallow amniotic fluid)

Question 2

Understand the anatomic features and pathogenesis of Infantile hypertrophic pyloric stenosis

Answer 2

Causes narrowing of antrum and obstruction at the level of the pylorus. Proximal stomach becomes dilated. Presents around 3rd week of life with non-bilious, projectile vomiting, associated with upper abdominal mass (olive shaped)

Pathogenesis: Hypertrophy and hyperplasia of smooth muscle in gastric wall at pylorus.

Both genetic and environmental factors play a role.

Question 3

Understand the anatomic features and pathogenesis of Meckel diverticulum

Answer 3

Small blind pouch protrudes from intestines, often in distal ileum. Usually 2-3 cm. Often contains gastric or pancreatic tissue

Usually asymptomatic. Presents about 2 years of age, obstruction (intussciception), bleeding and inflammation

Pathogenesis: Abnormal remnant of vitelline duct (connection between yolk sac and intestine). A failure to obliterate during development.

Question 4

Understand the anatomic features and pathogenesis of Omphalocele vs Gastroschisis

Answer 4

Omphalocele: Portion of intestines outside abdominal wall. Intestines contained within peritoneal and amniotic covering. Caused by failure of intestines to return to abdomen following physiological herniation (6-10wks development)

Gastroschisis: Portion of intestines outside of abdominal wall. NOT contained by amniotic covering. Caused by defect in abdominal wall that allows herniation with increased intra-abdominal pressure

Question 5

Understand the anatomic features and pathogenesis of Intestinal malrotation

Answer 5

Intestines do not assume normal position in the abdomen. Can cause midgut volvulus (obstruction).

Usually asymptomatic, but can present with bilious vomiting due to obstruction.

Caused by abnormal rotation (during weeks 6-10 of development) and fixation of tract

Question 6

Understand the anatomic features and pathogenesis of Gastrointestinal duplications/cysts

Answer 6

Saccular/cystic or tubular structures which contain normal bowel layers and may communicate with other segments of bowel

Often asymptomatic. Presents with cystic mass or intestinal obstruction

Most commonly duplicates in small bowel

Question 7

Understand the anatomic features and pathogenesis of Intestinal stenosis/atresia

Answer 7

Portion of bowel us narrowed, or ends in a blind pouch.

Most commonly in duodenum, frequently associated with Down Syndrome.

Presents prenatally as polyhydramnios or postnatally as obstruction with bilious vomiting

Etiology unknown

Question 8

Understand the anatomic features and pathogenesis of Imperforate anus/rectal agenesis

Answer 8

Opening of anus is missing or blocked. In worse cases, the lower portions of the bowel may be missing entirely.

Often coexist with fistula into bladder, urethra or vagina. Associated with other anomalies

Question 9

Understand the underlying developmental abnormality in Hirschsprung Disease

Answer 9

Defect of the enteric nervous development often caused by mutation in RET receptors or ligand and/or endothelin receptor genes. Both Auerbach and Meissner plexi fail to form, resulting in a portion of bowel that has not ganglion cells. Lack of ganglion cells prevents normal peristalsis and the portion of bowel cannot propel stool through bowel = secondary dilation of the proximal segment of colon called congenital megacolon

Question 10

Understand the predisposing factors and proposed pathogenesis of Necrotizing Enterocolitis

Answer 10

Complication of prematurity which develops within the first 7-10 days after the bowel wall. Invasion of bacteria flora combined with immune immarturity and ischemia leads to gas gangrene and perforation with peritonitis.

Most commonly in terminal ileum, cecum and right colon.

Commonly presents in premature babies as feeding intolerance, abdominal distension and bloody stools

Treated with bowel rest (NPO) and antibiotics. Surgical resection if refractory.

Question 11

Compare and contrast allergic and reflux esophagitis

Answer 11

Allergic: Result of immune reaction to dietary allergens. More severe eosinophilic intraepithelial infiltration with submucosal involvement that may include fibrosis. NO response to acid-blocking drugs. Treated with dietary modifications and steroids

Reflux: Result of poor gastroesophageal sphincter function, allowing gastric acid to reach the esophagus and damage epithelium. Respond to acid blocking drugs. Mild eosinophilic intraepithelial infiltrate