B5.032 - Gastric Ulcer Flip Flashcards
normal pH of the stomach
1-2
common symptoms of a gastric ulcer
epigastric abdominal pain location of the pain is important but one of the main characteristics is periodicity can present with bleeding or perforation
why do ulcers develop
bodys defenses have been overwhelmed levels of acid and pepsin in the stomach overwhelm mucosal defense mechanisms
describe pepsin
proteolytic at an acidic pH helps break down things
describe acid secretion
ACh from gastrin neurons –> M3 receptors –> intracellular calcium gastrin from antral G cells –> CCK2 receptors –> intracellular calcium histamine from oxyntic ECL cells –> H2 receptors –> cAMP pathway
summarize acid secretion
what is the main inhibitory mechanism againts acid secretion
somatostatin
main risk factors for gastric ulcers
Hp infection - most
NSAID use
ZEZ
why does H pylori cause ulcers in stomach and not other places
stomach mucosa has specific receptors for H pylori
doesnt invade gastric cells but attaches itself to receptors expressed itself on the gastric surface
H pylori causes inflammation that leads to increased secretion, which the bacteria use as a source of nutrients
why does H pylori lead to a gastric ulcer in some but duodenal in others
antral gastritis causes decreased production of somatostatin that leads to increased production of gastrin and acid secretion, which then leads to a duodenal ulcer
how do NSAIDs cause gastric ulcers
decreased mucus production by inhibiting COX 1 enzyme with reduced prostaglandin secretion
procedure of choice for diagnosis of gastric ulcer
EGD
radiography has limited role
CT is diagnostic modality of choice when perforation suspected
describe proton pump inhibitors
a true love bond between sulfenamide in PPI and cysteine in H+K+ATPase
what types of surgical treatments could work for ulcers
vagotomy
distal gastrectomy
what will happen when the body starts producing excess gastrin
the basal and maximal acid output iwll increase
ulcers will develop in unusual locations
what is ZE
a tumor gastrinoma produces excess gastrin that causes excessive gastric acid to be produced and cause ulcerations
what is mastocytosis
mast cells produce excessive histamine to increase gastric acid production
primary gastric cells to secrete acid
parietal cells
neurogenic control of acid secretion
vagus nerve via acetylcholine
primary gastric cells to secrete somatostatin that inhibits gastric acid
D cells in pylorus
primary gastric cells to secrete pepsin
cheif cells
primary gastric cells to secrete histamine
ECL cells
final common pathway to secrete acid
H+K+ATPase
how to you treat gastric ulcers
treat or remove offending agent
reduce acid production
what are 3 ways we block acid secretion
histamine receptor type 2
PPIs
vagotomy and/or distal gastrectomy
