GIT Flashcards
Why is Meckel’s diverticulum a true diverticulum?
It contains all 3 layers of mucosa, submucosa, and muscularis
Rule of 2s of Meckel’s
2% of population, within 2 feet of ileocecal valve, 2x more in males, most often symptomatic by age 2
Associations of pyloric stenosis
Turner syndrome, trisomy 18, erythromycin/azith exposure in 1st 2 weeks of life
The normal segment in Hirschsprung’s
The dilated segment (whereas the constricted is aganglionic)
Functional disorder of the esophagus is associated with this diverticulum above the UES
Zenker’s diverticulum (pharyngoesophageal)
Anatomic obstruction of the esophagus because of mucosal webs, associated with IDA, glossitis, cheilosis
Plummer-Vinson syndrome (IDA, glossitis, cheilosis, and esophageal webs)
Esophageal rings
Schatzki rings
Triad of achalasia
Incomplete LES relaxation, increased LES tone, esophageal aperistalsis
Etiology of achalasia
Distal esophageal inhibitory neuronal degeneration (parang Hirschsprung’s) in primary, Chagas disease in secondary achalasia
Definition of Barrett’s esophagus
Intestinal metaplasia of squamous epithelium + goblet cells + key endoscopic findings
Distinguishing feature between functional and obstructive (ex. from CA) dysphagia
Functional - both solids and liquids, cancer - solid first, liquid later
Proximal duodenal ulcers associated with severe burns and trauma
Curling ulcers
Esophageal, gastric, and duodenal ulcers associated with increased ICP
Cushing ulcers
Most common cause of chronic gastritis
H. pylori gastritis
Most common cause of diffuse atrophic gastritis
Autoimmune gastritis
Microbiological characteristics of H. pylori
Gram-negative, microaerophilic, urease-positive, helical bacterium
Virulence factors of H. pylori
Urease (creates NH3 from urea, elevating gastric pH), CagA toxin (associated with multifocal atrophic gastritis and consequently gastric adenoCA), flagella, adhesins
Cells targeted by autoimmune gastritis
Parietal cells (decreased HCl and intrinsic factor -> pernicious anemia)
Unique sequelae of H. pylori gastritis
MALToma
Unique sequelae of autoimmune gastritis
Carcinoid (due to endocrine cell hyperplasia)
Location of H. pylori gastritis
Antrum (vs body for autoimmune gastritis)
Characteristics of gastric ulcers
Occurs with meals and associated with gastric adenoCA
Characteristics of duodenal ulcers
Relieved by meals, nocturnal awakening, NOT associated with gastric adenoCA
Morphological feature that will make you suspect malignancy in gastric ulcers
Heaped up margins
Hypoproteinemia due to protein-losing enteropathy from hypertrophic gastropathy
Menetrier disease
Triad of Zollinger-Ellison
Pancreatic islet cell tumor (gastrinoma), gastric hypersecretion, and intractable PUD
Most common site of extranodal lymphoma
Stomach (MALTomas due to H pylori gastritis)
Most important prognostic factor of GI carcinoids (most commonly found in small intestines)
LOCATION (if midhut, tends to be multiple and aggressive)
Cytogenetic origin of GIST
Interstitial cells of Cajal (muscularis propria)
Most common cause of intestinal obstruction
Hernia
Most common cause of intestinal obstruction in children
Intussusception
Two types of ischemic bowel disease
Mural (mucosa and submucosa) and transmural (involves all three layers, most commonly due to arterial occlusion
Hallmark of malabsorption syndromes
Steatorrhea
Cell-mediated immune enteropathy on exposure to gliadins (in gluten)
Celiac disease
Most sensitive morphologic indicator in celiac disease
CD8 cytotoxic T cells in villus
Most sensitive serologic indicator in celiac disease
Antibodies vs transglutaminase
Most common malignancy associated with celiac disease
Enteropathy-associated T cell lymphoma
Two kinds of inflammatory bowel disease
UC and Crohn’s disease
Bowel wall involvement of Crohn’s vs UC
Crohn’s - transmural (full thickness), UC - mural only (up to submucosa)
Organ involvement of Crohn’s vs UC
Crohn’s - any part of the GI tract (SKIP LESIONS), UC - colon and rectum (UU lang!)
Hallmark of Crohn’s
Noncaseating granulomas and Paneth cells in L colon
Uniquely found only in UC but not Crohn’s
Toxic megacolon
Most common site of diverticulum
Sigmoid
In adenomatous polyps, the single most important factor that relates to malignancy risk
SIZE (>4 cm)
If the degree of dysplasia in a GI polyp extends to the lamina propria and muscularis mucosa, then it is…
Intramucosal CA (beyond that, invasive CA)
This colonic polyp is more commonly found in the R colon and is characterized by elephant feet glands and high malignant potential
Sessile serrated adenoma (vs L colon for hyperplastic polyp)
Rare, AD d/o with multiple hamartomatous polyps and mucocutaneous hyperpigmentation with arborizing networks
Peutz-Jegher
Syndrome of multiple colorectal adenomas as teenagers
FAP (mutation in APC of Ch5, more than 100 polyps and develop colonic adenoCA by age 30) BECAUSE TEENS LIKE TO FAP
Familial clustering of colorectal, endometrial, gastric, ovarian, ureter, brain, small bowel, HBT, pancreas, and skin CA
HNPCC or Lynch syndrome (mutation in MSH2 and MLH1) because they’ll lynch you from head to toe
T or F NSAIDs are protective vs adenoCA of the colon
TRUE
Causes pseudomyxoma peritonei
LAMN (low grade appendiceal mucinous neoplasm)
