Congenital Abnormalities Within GI Tract Flashcards
Atresia vs fistula vs duplications
Atresia
- congenital narrowing of blood vessels/GI tract
- agenesis = complete absence
Fistulae
- congenital abnormal connection between two hollow spaces (usually blood vessels, intestines or other hollow organs)
Duplications
- congenital splitting/coupling of two hollow organs/blood vessels and/or intestines
generally, require prompt surgical repair and are incompatible with life
Secondary causes from fistula of esophagus
Usually fistula results in connection of esophagus to the trachea which causes
- aspiration
- suffocation
- pneumonia
- fluid/electrolyte
Development abnormalities of the esophagus are also associated with what kind of congenital diseases?
Heart defects
Genitourinary malformations
Neurologic genetic disorders
Where in the intestines does atresia occur at the most often?
Duodenum
Imperforate anus
Most common form of congenital intestinal atresia
- is due to the cloacal diaphragm to involute
Stenosis
Incomplete atresia in which the lumen is markedly reduced as a result of fibrosis thickening of the lumen wall
- can result in partial or complete obstruction
Can involve any part of the GI tract, but most commonly hits the esophagus and small intestine
Diaphragmatic hernia
Incomplete formation of the diaphragm which allows for the abdominal viscera to herniate into the thoracic cavity
- often causes pulmonary hypoplasia and in severe cases, incompatible with life
Omphalocele
Abdominal musculature incompletely closes, which results in the abdominal viscera to herniate into a ventral membranous sac
Requires surgical repairment and roughly 40% of infants that have this also have other compounding birth defects
Gastroschisis
Similar to omphalocele except that all layers of the abdominal wall including peritoneum and skin are affected
- not just abdominal viscera
Is more dangerous and is surgically correctable
Ectopic tissues
Developmental arrest and movement of site specific tissues outside of normal site area specific.
- most frequent ectopic gastric mucosa = upper third of the esophagus (causes “inlet patch”)
Other areas are
- pancreatic tissues in the esophagus or stomach
- gastric heterotopia mucosa in the small bowel or colon
gastric heterotopia often causes occult blood less due to peptic ulcerations due to acid secretion
Meckel diverticulum
A blind outpouching of the alimentary (GI) tract in the ileum
- contains all layers of bowel wall and the lumen of the bowel
Results from failed involution of the Vitelline duct (connects developing duct to yolk sac)
*most common type of diverticulum
“Rules of 2’s” for meckel diverticulum
2% occurrence rates
Generally present within 2 feet of ileocecal valve
Are approximately 2 inches long
2x as common in males
Most often symptomatic by age 2 (if they ever become symptomatic)
What does meckel diverticulum often mimic if it becomes symptomatic?
Acute pancreatitis
- this is because the ileum is in the same region as the pancreas
Congenital hypertrophic pyloric stenosis epidemiology
Occurs in 1:300-900 live births
3-5x more common in males
Is highly genetic (monozygotic twins have a 200x increase in risk; dizygotic = 20x)
Is correlated with Turner syndrome (trisomy 18)
Antibiotics erythromycin and azithromycin exposure in newborns increases risk as well
Congenital hypertrophic pyloric stenosis pathogenesis
Occlusion of the pyloric sphincter preventing food to leave stomach due to extreme hypertrophy of the pyloric muscularis PROPRIA layer -> small intestines
- looks like a firm ovoid abdominal mass on imaging
Appears between 3-6 weeks old as new-onset regurgitation projectile nonbilious vomiting with dehydration and weight loss
- may also show left -> right visible hyperperistalsis (can see the stomach trying to push the food through the pyloric stenosis)
Treatment = surgical intervention cures
