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Flashcards in Pathophysiology of Stomach Deck (19):
1

Pathophysiology/sx of gastroparesis

  • delayed gastric emptying ==>
  • early satiety
  • epigastric fullness
  • pain
  • bloating
  • nauseau
  • vomiting

2

Causes of gastroparesis

  • post-surgical states
  • endocrine disorders (diabetes, hypothyroidism)
  • muscular disorders
  • systemic sclerosis
  • drugs**
    • narcotics
    • TCADs
    • clonidine
  • vagal n. dysfxn**
    • most common: secondary to autonomic damage from diabetes
  • post-viral**
    • norwalk
    • rotavirus

3

Epidemiology of Helicobacter pylori gastritis

  • @ developed countries: age-related prevalence
  • correlated w/socioeconomic status and crowded living conditions
  • many people are infected by H. pylori, but not everyone develps peptic ulcer disease 

4

Pathophsyiology of H. pylori

  • H. pylori = gram-neg. rod that produces abundant urease ==> ammonia ==> higher local pH
  • escapes gastric juice by colonizing surface epithelium
  • virulence factors:
    • adhesins
    • phospholipase
    • cytotoxins
    • cytokines
    • urease
    • CagA
  • elicits robuts inflammatory response ==> damage to epithelium/mucosal layer

5

Testing for H. pylori infection

  • mucosal biopsy
    • histological demonstration
    • CLO test = detects presence of urease
      • blood in stomach, PPI use, or H2 antagonists  ==> often false negative rapid urease
  • blood antibody tests
    • IgG ELISA ab test
    • ==> false positives due to low prevalence 
    • cannot be used to corfirm infection eradication
  • urea breath test (UBT)
  • stool antigen test
    • **most commonly used to determine eradication

6

Phenotypic forms of H. pylori gastritis

  1. mild, diffuse chronic active superficial gastris ==> no sx/disease
  2. antral predominant gastritis + spared gastric body ==> high levels of acid secretion ==> duodenal ulcer
  3. mutifocal atrophic gastritis ==> low acid secretion ==> gastric ulceration OR gastric metaplasia/dysplasia ==> gastric adenocarcinoma

7

H. pylori treatment

  • First line:
    • proton pump inhibitor (antibiotics work better at a more neutral pH)
    • amoxicillin 1 gm
    • clarithromycin 500 mg
    • all 2x/day for 7-14 days
  • after failure of first line = "classical quadruple therapy"
    • PPI
    • bismuth
    • tetracycline
    • metronidazole

8

Ulceration definition

  • lesion greater than 5mm in diameter w/depth that breaches muscularis mucosa

9

Pathophysiology of NSAID-induced injury

  • NSAIDs ==> prostoglandin depletion
  • pts w/prior ulcer disease and elderly @ increased risk
  • gastric or duodenal (less common) ulcers

10

COX-2 selective antagonists relation to ulcers

  • developed to decrease gastro-duodenal damage b/c do not inhibit PG formation @ GI tract
  • ==> fewer ulcers and complications
  • **removed from market b/c increased risk of myocardial infarction

11

Pathophsyiology of Peptic Ucler Disease

  • occur when gastroduodenal mucosal defenses are unable to protect epithlium from acid and proteases
  • predisposing factors: H. pylori infection, NSAID use.

12

Clinic manifestations of peptic ulcer disease

  • burning epigastric pain
    • may awaken patient from sleep
    • relieved by antacids
    • intermittent pain

13

Common complications of ulcers

  • bleeding (30% of PUD pts)
  • anemia
  • perforations/penetration
    • penetration ==> another structure (liver, pancreas)
    • perforation ==> peritoneum
  • obstruction <== edema surrounding ulcer or scar tissue
    • nausea, vomiting, early satiety

14

Most common gastric neoplasms

  • adenocarcinoma
  • gastric polyps
  • stromal tumors/GIST
  • neuro-endocrine tumors
  • lymphoma

15

Characteristics of gastric adenocarcinomas

  • histologic = diffuse vs. intestinal
    • diffuse = less common
      • signet-ring cells
      • excess mucin production
    • intestinal = glandular
      • assoc. w/atrophic gastritis & intestinal metaplasia
  • prevalence: becoming less common in US
  • closse association w/chronic H. pylori gastritis
  • overall 5-year survival = 10%

16

Characteristics of gastric polyps

  • 3 types: adenoma, hyperplastic, and fundic gland
  • hyperplastic = most common
    • assoc. w/hypergastrinemia
    • autoimmune body gastritis
    • no risk of transformation to adenocarcinoma
  • adenoma = poses cancer risk
  • fundic glad = most likely benign

17

Stromal tumors

  • benign = leiomyomas & lipomas
  • malignant = leimyosarcoma & lipsarcoma
  • location: submucosal, subserosal or both="dumbbell" configuration
  • larger tumors assoc. w/abdominal pain or GI bleeding
  • GIST (GI stromal tumors)
    • express c-KIT = transmembrane tyrosine kinase
    • good response to imatinib (tyr. kinase inhibitor)
    • arise from interstitial cells of Cajal (GI pacemakers)

18

Characteristics of neuro-endocrine tumors

  • carcinoid tumors arise from enterochromafin or enterochromaffin-like cells
  • carcinoid tumors of stomach = relatively rare
    • usually fundus or body
    • sporadic
    • carcinoid tumor in pts w/achlorhydria secondary to atrophic gastritis
      • high levels of gastrin
  • second-most common cause of duodenal tumor after adenocarcinoma

19

Characteristics of lymphoma

  • strong assoc. w/ H. pylori infection and primary gastric B-cell lymphoma