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30 Cards in this Set
- Front
- Back
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Peptic ulcer:
What is it? Complications? |
Break in mucosa greater than 5mm, with depth to sub-mucosa
Complications: Bleeding Perforation Stenosis (narrowing) Malignancy (can present as ulcer) |
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Causes of duodenal ulcers.
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Mostly H pylori, some due to NSAIDs (10%)
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Causes of gastric ulcers.
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Mostly H pylori, A LOT more due to NSAIDs (30%), some due to cancers (10%)
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Parietal cells are found in the ____ of the stomach.
Where in the gland are they located? What do they secrete? |
Parietal cells found in CORPUS
Parietal cells located near apex of gland secrete HCl and IF |
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Chief cells are found in the ____ of the stomach
Where in the gland are they located? What do they secrete? |
Chief cells located in corpus of stomach
Located near basal aspect of gland Secrete pepsinogen |
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Surface mucus cells:
Apical/Basal Secretions |
Apical
Secrete mucus and HCO3- (protect stomach from being digested by HCl) |
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Neuroendocrine cells:
Subtypes, their location and secretions Apical/basal |
All neuroendocrine cells are basal (but not as basal as chief cells) in gland
G Cells: Gastrin, in antrum D Cells: Somatostain, everywhere ECL (enterochromaffin-like) cells: histamine; corpus |
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Parietal Cells:
What structural changes occur when going from resting to active form? |
Tubulovesicles-->Canaliculi to increase surface area for HCl to release from
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What stimulates parietal cells to secrete acids?
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1) vagal nerve stimuln (think, smell, see food) Ach
2) H2-receptor receives histamine from ECL cell (ECL cells release histamine in response to vagal stimulation as well) |
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Cephalic vs Gastric Phase of Gastric Secretion
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Cephalic: think, see, smell food (cholinergic, vagus)
Gastric phase: eat food; amines and distention-->secrete gastrin from G cells-->acid release |
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Events of intestinal phase of gastric secretion.
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Fat in duodenum stimulates multiple GI peptides (SOMATOSTATIN)-->inhibits gastrin and acid secretion
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Pre-epithelial defenses of stomach
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Mucus
Bicarb |
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Epithelial defenses of stomach
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Apical barrier of tight jns to prevent H+ back diffusion
Restitution/replication: should stomach lining be injured, neighboring cells will flatten out and adjacent cells divide to fill in gap (regulated by EGF, TGFalpha, trefoil peptides) |
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Subepithelial defenses of stomach
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Blood flow (lack of blood flow will result in ulcers!)
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Why do NSAIDs result in peptic ulcers?
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NSAIDs inhibit production of prostaglandins. Prostaglandins are essential to gastroduodenal defense mechanisms (pre-epith, epith, and subepith!)
More specifically: Direct injury Indirect injury via COX-inhibition and anti-platelet effects |
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Duodenal ulcers:
Pathophys |
Inc'd basal acid output
Inc'd peak (digestive) acid output Inc'd meal-stimulated acid output Lose negative feedback (somatostatin secretion) |
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Key difference between duodenal and gastric ulcers.
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Gastric ulcers have normal or low acid secretion.
Duodenal ulcers have elevated acid secretion. |
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H. pylori:
Gram -/+ Virulence factors |
Gram (-)
Virulence factors: VacA (vacuolating cyotoxin) cag pathogenicity genes--inserts into gastric epithelial cells causing release of pro-inflammatory cytokines |
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H. pylori:
Risk factors Age of transmission Method of transmission |
Inc'd age, poverty, overcrowding, foreign-born (developing countries)
Transmission during childhood Transmission: oro-fecal |
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H. pylori infection:
Patient effects |
100% get chronic superficial gastritis
Of these pts: 10% develop peptic ulcer dz 20% atrophic gastritic-->1-2% carcinoma <1%-->lymphoma so, 70% remain with chronic superficial gastritis (ASYX) |
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H. pylori:
Pathophysiology Effects on gastric physiology |
Direct cell damage
Degrades mucus Induces immune response in gastric mucosa f/x on gastric physio: Dec'd somatostatin, inc'd gastrin |
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SNPs affecting inflammatory response to H. pylori.
Associated outcome with SNPs. |
High IL-1beta and TNF-alpha-->gastric cancer
Normal/Low IL-1beta & TNF-alpha-->duodenal ulcer |
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Rapid urease test
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H pylori test
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H. pylori:
Dx |
Stool antigen
Urea breath test--pt swallows radio-labeled urea, if have h. pylori, urea will be split into CO2 and can be measured (will be radioactive) Don't do serology (Ab's): it's lame. |
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NSAID:
Examples Sites of ulcerations What other damage can they cause to these areas? |
ASA, ibuprofen, naprosyn
Sites of ulceration: Stomach > duodenum >> intestine Can also cause erosions, petechiae, hemorrhages, occult bleeding (manifests as anemia); OFTEN ASYX |
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NSAID injury risk factors.
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Old people that take many drugs
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Gastrinoma:
What is it? Associated diseases Presentation |
Tumor that secretes gastrin
Assocd w/MEN I (parathy, panc, pit) Up to 50% mets at presentation! Presentation: SEVERE ulceration, +/- diarrhea |
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Zollinger-Ellison Syndrome:
What is it? |
Gastrinoma!
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Stress-induced ulcers:
Pathophys |
Common in pts in ICU
Head is being shunted to brain, results in chronic ischemia of stomach-->ulceration |
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Acid inhibition treatment:
DU vs GU |
DU: 1qd x 4 weeks
GU: 1 qd x 8 weeks |
