Flashcards in Peptic Disease Deck (37)
How do prostaglandins inhibit acid secretion?
they target a receptor on the serosal surface of the parietal ell. Throuh a G protein on adenylate cyclase, causing a decrease in cAMP.
What chemical induces acid secretion in the cephalic phase?
The arrival of food and acid in the small bowel trigger the release of what two chemicals? What do they do together?
CCK and Secretin are secreted upon arrival of food in the small bowel, and they feedback to inhibit acid secretion in the stomach.
What prevents the stomach from being degraded and destroyed by it's own acidity and enzymes?
the mucous-bicarbonate layer which causes a ph gradient on the surface.
What is Peptic Ulcer Disease?
a defect in GI mucosa extending through muscularis mucosae
What are symptoms of peptic ulcers?
epigastric burning, may be nocturnal or relieved with food.
May be asx (common with NSAIDS and elderly)
What are risk factors for PUD
medicines (nsaids, asa, clopidogrel)
What chronic dz have ulcers associated with them?
icu pts on ventilators
What does h pylori produce?
urease - making it resistant to gastric acid
What is the morphology of h pylori
spiral-shaped, gram- bacteria with four to six unipolar sheathed flagella.
What is the mechanism of h pylori?
secretes factors, a peptide, and LPS, which are cehmotactic for neutrophils and monocytes. heat, acid and alkali stable. the inflammatory cells, once recruited, will then release oxygen radicals, prostaglandins, interleukin, and tumor necrosis factor that will fruther promote additional inflammation.
What are high risk factors for nsaid gi toxicity?
history of a previously complicated ulcer,
over 65 yo
high-dose nsaid therapy
previous history of uncomplicated ulcerconcurrent use of aspirin, glucocorticoids or anticoagulants
What are some causes of pud
increased vagal activity
parietal cell hyperplasia
acid erosive injury
what are complicatoins of pud
bleeding - hematemesis, melena, anemia
gastric outlet obtruction (vomiting 3-4 hrs post eating)
What is a dz that causes pud?
how can we tx pud?
anti-secretory agents-h2 blockers ppis
eradicate h pylori
avoid smoking, nsaids and asa
What are tests for h pylori?
urea breath test. (no bismuth, ppi or abs)
fecal antigen test using mab
is pud or erosive gastritis more superficial
what does the "blood under plastic wrap" refer to?
hemorrhagic gastritis with multiple subepithelial hemorrhages without any visible breaks in mucosa.
what is associated with acute hemorrhagic gastritis
alcohol, non-steroidal, anti-inflammatory agents, bile reflux, trauma, burns, sepsis, shock
how do you present with acute hemorrhagic gastritis
abd discomfort, pain heartburn n/v hematemesis (can be massive)
What is the main cause of chronic gastritis?
what does nichols say about h pylori gastritis?
common, increasing with age, severe in antrum, lymphocytic infiltration, with germinal centers and neutrophils (which make it active). leads to gastric adenocarcinoma
What stain detects h pylori?
What is the most important toxin assocaited with h pylori?
cytotoxin-associated gene A - CagA protein
what does CagA protein do?
It's the h pylori toxin that degreades p53. Activates pathways to cell proliferatoin and messes up cell polarization.
How does CagA get into cells?
It's injected by type IV secretion sytem t4ss pilus structure
If you have g-cell hyperplasia, do you have AI gastritis or h pylori?
Describe the gross appearance of ulcers
round, deep, punched out