Pediatric Gastrointestinal Pathology Flashcards
Are atresias and stenoses more common in foregut or hindgut?
foregut
Esophageal atresia occurs most often in association with a _____ to the trachea
fistula
85-90% of atresias have a _______ and a _____ between the lower part of the esophagus and trachea
blind upper esophageal segment and a fistula
Clinical presentation of atresia and fistula
aspiration, regurgitation, respiratory distress with initial feeds, absence of GI gas pattern on x ray, 50% of children have other anomolies, trisomy syndromes, VATER association
Where do duodenal stenoses tend to occur?
proximally near the ampulla of vater
Etiologies of duodenal stenoses
- web; from failure of proper recanalization during development
- annular pancreas: secopancreasnd portion of duodenum completely or partially surrounded by
Clinical presentation of duodenal stenosis
vomiting at birth, bilious if distal to the ampulla, double bubble xray
Are jejunoileal atresias more often single or multiple?
85% single
Etiologies of jejunoileal atresias
intrauterine vascular accidents, volvulus, hernias, necrotizing enterocolitis
Clinical manifestation of jejunoileal atresia
- proximal = vomiting
2. distal = distension and dilated radiographic loops
How are anorectal atresias classified?
high = above levator sling and associated with GU fistulae low = associated with perineal fistulae
2 gastric wall defects
- omphalocele: covered by amniotic sac, due to failure of complete fusion of umbilical ring during withdrawal of intestine
- gastroschisis: complete failure of formation of peritoneum, muscle, and skin of abdomen
Short Bowel Syndrome pathogenesis
loss of bowel surface, reduced reabsorption, nutrient deficiency, diarrhea
Most common indication for bowel transplant in children
short bowel syndrome
Etiologies of SBS in younger children
congenital gastroschisis, voluvulus, atresia (60%) or NEC (40%)
Etiologies of SBS in older children
volvulus, trauma, neoplasia
GI duplication
development of a duplication of a segment of GI tract –> usually in mesenteric side of bowel
What is the most common site of GI duplication?
terminal ileum –> usually share wall but do not communicate with intestine
GI diverticuli are mostly located on which side of the bowel?
antimesenteric
Pathogenesis of GI diverticuli
failure to close vitelline duct –> most common is meckel’s diverticulum
By what week of development is the vitelline duct usually obliterated?
10th week
What is inside a GI diverticulum?
50% contain gastric mucosa –>tend to be symptomatic because of acid damage –> rectal bleeding
Neurenteric remnant or cyst
originate form dorsal midline GI tract and attach or pass through vertebrae and spinal cord
Most common location for neurenteric remnant
cervical/lumbar spine
clinical signs of neurenteric remnant
dorsal cutaneous hypertrichosis or hyperpigmentation + GI obstruction, respiratory distress, and CNS paralysis/infections/chemical meningitis
Category of disorders characterized by signs and symptoms reflecting physical obstruction to luminal flow without true mechanical obstruction
pseudo-obstruction
Most frequent primary enteric psuedo-obstruction
Hirschsprung disease
Secondary etiologies of pseudo-obstruction
chagas disease, toxic megacolon, dystrophies, etc
2 classes of primary pseudo-obstruction
enteric neuropathies and visceral myopathies
The enteric nervous system arises mostly from the _____ neural crest cells which populate the gut in a cranio-caudal fashion.
vagal
Failure of normal migration of enteric neural crest cells results in _____
aganglionisis
Pathophysiology of aganglionosis
No neural crest miration = no ganglion = no propulsion in the intestine
Hirschsprung disease incidence
1/5000
Dx of Hirschsprung disease
finding of absence of ganglion cells in rectal biopsy
Which 2 genes are most associated with Hirschsprung?
- ret in 50% of family and 15% of sporadic
2. 10% down syndrome
Where is Hirschsprung usually located?
usually distal and limited but rarely exists in the cranial intestine
Most common GI emergency in newborns
necrotizing entercolitis
T/F most infants with NEC are premature
T –> 90% premature and most very low birthweight
Most important contributing factors to NEC
intestinal ischemia, intestinal immaturity, bacterial colonization of gut, enteral feeding
Clinical signs of NEC
first 2 weeks of life: abdominal distension, bloody stools, apnea, gas in bowel wall (pneumatosis)
Intussusception
results from invagination of one intestinal segment into the other
Most common cause of intestinal obstruction in childhood
Intussusception
Cystic fibrosis is AD/AR
recessive –> 1/3200 births
Primary cystic fibrosis defect
CFTR chloride chanel
GI effect of CF
thick mucus, decreased ciliary clearance, reduced Cl- secretion, less water, dilated glands, meconium ileus, pancreatic atrophy
meconium ileus
obstruction of intestinal lumen by viscid meconium –> most cases occur in patients with CF
