Path: Congenital, Esophagus, Stomach Flashcards
absence of the esophagus (rare)
agenesis
incomplete development of the esophagus
atresia
usually associated with a fistula connecting the upper and lower esophageal pouches to a bronchus or the trachea
atresia
- occurs most commonly at or near the tracheal bifurcation
what does intestinal atresia frequently involve?
duodenum
incomplete form of atresia in which the lumen is markedly reduced in caliber as a result of fibrous thickening of the wall
stenosis
- can be acquired as a consequence of inflammatory scarring, such as chronic gastroesophageal reflux
when incomplete formation of the diaphragm allows the abdominal viscera to herniate into the thoracic cavity
diaphragmatic hernia
when closure of the abdominal musculature is incomplete and the abdominal viscera herniate into a ventral membranous sac
omphalocele
similar to omphalocele, except it involves all of the layers of the abdominal wall, from peritoneum to the skin
gastroschisis
where is the most common site of ectopic gastric mucosa?
inlet patch (upper third of the esophagus)
found in the esophagus or stomach, like inlet patches, these nodules are most often asymptomatic but they produce damage and local inflammation
ectopic pancreatic tissue
small patches of ectopic gastric mucosa in the small bowel or colon, may present with occult blood loss due to peptic ulceration of adjacent mucosa
gastric heterotopia
blind outpouching of the alimentary tract that communicates with the lumen and includes all three layers of the bowel wall
true diverticulum
what are the two most common forms of atresia?
- esophageal atresia
- imperforate anus (most common intestinal atresia), due to failure of cloacal diaphragm to involute
what is the most common true diverticulum? where does it occur?
Meckel diverticulum, occurs in the ileum
occurs as a result of failed involution of the vitelline duct, which connects the lumen of the developing gut to the yolk sac
- solitary diverticulum extends from the anti-mesenteric side of the bowel
Meckel diverticulum
what are the “rule of 2’s” of Meckel diverticula?
- 2% of population
- present within 2 feet of the ileocecal valve
- are approx 2 inches long
- twice as common in males
- more often symptomatic by age 2
the mucosal lining of Meckel diverticula may resemble what?
normal small intestine, but ectopic pancreatic or gastric tissue may also be present
- the latter may secrete acid, causing ulceration of adjacent small intestinal mucosa
3-5 times more common in males, occurs one in every 300-900 live births
- monozygotic twins have 200-fold increased risk if one twin affected
- dizygotic twins have 20-fold increased risk
- Turner syndrome and trisomy 18 have increased risk
- erythromycin or azithromycin in the first 2 weeks of life has been linked to increased incidence
pyloric stenosis
presents between the third and sixth weeks of life as new-onset regurgitation, projectile, non-bilious vomiting after feeding, frequent demands for refeeding
congenital hypertrophic pyloric stenosis
when does pyloric stenosis present in adults?
- surgical splitting of the muscularis (myotomy)
- can be acquired as a consequence of antral gastritis or peptic ulcers close to the pyloris
10% of cases occur in children with Down syndrome (genetic component present in nearly all cases)
- results when neural crest migration from cecum to rectum is arrested prematurely or when the ganglion cells undergo premature death
Hirschsprung disease (congenital aganglionic megacolon)
what is the result of “aganglionosis” in megacolon?
the distal intestinal segment lacks both the Meissner submucosal and the Auerbach myenteric plexus
- coordinated peristaltic contractions are absent and functional obstruction occurs -> resulting in dilation proximal to the affected segment
heterozygous LOF mutation in receptor tyrosine kinase RET account for majority of familial cases of what?
Hirschsprung disease
how can ganglion cells be identified using immunohistochemical stains?
Ach
- they also have characteristic morphology in hematoxylin and eosin-stains
what part of the GI tract is always affected in Hirschsprung disease?
the rectum, but the length of additional segments varies widely
how does Hirschsprung disease present in the immediate postnatal period?
failure to pass meconium
- obstruction or constipation follows, often with visible, ineffective peristalsis
what are the major threats to life in Hirschsprung disease
enterocolitis, fluid, and electrolyte disturbances, perforation, and peritonitis
what is the primary mode of treatment of Hirschsprung disease?
surgical resection of the aganglionic segment, followed by anastomoses of the normal proximal colon to the rectum
how does acquired megacolon happen?
Chagas disease, obstruction by neoplasm or inflammatory stricture, toxic megacolon complicating ulcerative colitis, visceral myopathy, or in association with functional psychosomatic disorders
what develpps from the cranial portion of the foregut and is recognizable by the third week of gestation?
esophagus
high amplitude contractions of the distal esophagus that are due to loss of the normal coordination of inner circular layer and outer longitudinal layer smooth muscle contractions
nutcracker esophagus
repetitive, simultaneous contractions of the distal esophageal smooth muscle
diffuse esophageal spasm
what is present in many patients with nutcracker esophagus or diffuse esophageal spasm?
lower esophageal sphincter spasm
esophageal dysmotility may result in development of small diverticulae where?
immediately above the lower esophageal sphincter
impaired relaxation and spasm of the cricopharyngeus muscle after swallowing can result in increased pressure within the distal pharynx and development of what?
Zenker diverticulum
- are uncommon, but typically develop after age 50 and may reach several centimeters in size
fibrous thickening of the submucosa and is associated with atrophy of the muscularis propria as well as secondary epithelial damage
esophageal stenosis
- due to inflammation and scarring that may be caused by chronic gastroesophageal reflux, irradiation, or caustic injury
idiopathic ledge-like protrusions of mucosa that may cause obstruction
- typically occur in women older than 40 and can be assoc with gastroesophageal reflux, chronic graft v. host disease, or blistering skin diseases
esophageal mucosal webs
what might accompany webs in the upper esophagus?
iron-deficiency anemia, glossitis, and cheilosis (spoon nails) as part of the Paterson-Brown_Kelly or Plummer-Vinson syndrome
semi-circumfrential lesions that protrude less than 5mm, have a thickness of 2-4mm, and are composed of a fibrovascular connective tissue and overlying epithelium
esophageal webs
what is the main symptom of esophageal webs?
nonprogressive dysphagia associated with incompletely chewed food
circumferential, thicker, and include mucosa, submucosa and occasionally hypertrophic muscularis propria
esophageal rings aka Schatzki rings
what are esophageal rings called when they present in the distal esophagus, above the gastroesophageal junction, and are covered by squamous mucosa?
A rings
what are esophageal rings called when they present at the squamocolumnar junction of the lower esophagus, and may have gastric cardia-type mucosa on their undersurface?
B rings
triad of incomplete LES relaxation, increased LES tone, aperistalsis of the esophagus
achalasia
what are the symptoms of achalasia?
dysphagia for solids and liquids, difficulty belching, and chest pain
does achalasia warrant surveillance endoscopy?
no, there is not considered great enough risk for esophageal cancer
what is the result of distal esophageal inhibitory neuronal (ganglion cell) degeneration?
primary achalasia
what does primary achalasia lead to?
increased tone, inability to relax the LES, and esophageal aperistalsis
- degenerative changes in the extraesophageal vagus nerve or the dorsal motor nucleus of vagus nerve
Trypanosoma cruzi infection causes destruction of the myenteric plexus, failure of peristalsis, and esophageal dilation
secondary achalasia due to Chagas disease
the association of HSV1 infection, linkage of immunoregulatory gene polymorphisms, and occasional coexistence of Sjogren syndrome, or autimmune thyroid suggests what?
achalasia may also
