Wk2 Gastric Pathology Flashcards
Two normal damaging forces of gastric mucosa:
- Gastric acid
2. peptic enzymes
Six normal defensive forces of gastric mucosa:
- surface mucous secretion
- bicarb secretion into mucous
- mucosal blood flow
- apical surface transport
- epithelial regeneration
- elaboration of prostaglandins
Seven main mechanisms of gastric mucosal injury:
- H. pylori
- cigarette smoke
- alcohol
- NSAIDs
- Aspirin
- gastric hyperacidity
- duodenal gastric reflux
loss and necrosis of surface epithelium, confined to the lamina propria, i.e. mucosa
mucosal erosion
necrotizing process extends beyond the mucosa into the submucosa and even into and through the muscle wall
mucosal ulcer
Most common finding in H. pylori gastritis:
active chronic gastritis
antrum —> fundus
Two complications of H. pylori infection:
- MALT lymphoma
2. gastric adenocarcinoma
How do humans acquire H. helmannii gastritis?
letting dogs lick your face
Stain to help visualize H. pylori?
diff quick blue
Dx test for active H. pylori:
H. pylori stool antigen
urea breath test
rapid urease test on fresh tissue biopsy
Pathogenesis of autoimmune gastritis:
CD4+ T-cell mediated destruction of parietal cells
chief cells also lost during destruction of the gastric glands (“bystander damage”).
Antibodies to parietal cells and intrinsic factor are also produced as part of the autoimmune response, but are not pathogenic (can be used as a diagnostic test).
Findings in autoimmune gastritis:
Decreased gastric acid secretion (achlorhydria).
Compensatory hypergastrinemia and hyperplasia of antral gastrin-producing G cells
endocrine cell hyperplasia in the fundus and body of the stomach.
Vitamin B12 deficiency due to loss of secreted intrinsic factor (pernicous anemia with increased RBC MCV).
Reduced serum pepsinogen I concentration.
Inflammatory mucosal damage
atrophy of the gastric mucosa in the body and fundus with sparing of the antrum and cardia
Causes of chronic reactive gastropathy:
chemical mucosal injury
NSAIDs
aspirin
bile reflux
alcohol ingestion
Two common causes of peptic ulcer disease:
- H. pylori
2. NSAIDs
Three complications of PUD:
Bleeding
perforation
obstruction
eosinophilic inflammation
usually multiple GI sites
maybe food or other allergy
eosinophilic gastritis
characterized by marked intraepithelial inflammation (CD8+ T cells).
Can be seen as an isolated finding, or in patient’s with either co-existing celiac disease or in patients with co-existing ________/collagenous colitis
lymphocitic gastritis
granulomatous inflammation.
Most cases are secondary to an underlying disorder, such as Crohn’s disease, sarcoidosis, mycobacterial or fungal infections.
granulomatous gastritis
excessive secretion of transforming growth factor alpha (TGF-α).
marked diffuse hyperplasia of the foveolar epithelium of the body and fundus of the stomach
protein losing enteropathy and hypoproteinemia, with diarrhea, weight loss, and peripheral edema
Some cases of are associated with an infection (e.g. CMV in children).
Patients are also at risk for gastric adenocarcinoma.
Menetrier’s disease
Caused by gastrin secreting tumors:
Zollinger-Ellison syndrome
exaggerated mucosal response to chronic gastritis:
hyperplastic polyp
associated with PPI
increased gastrin in response to decrease acid
cystic fundic gland polyp
Neoplasm morphologically similar to other GI adenomas:
gastric adenoma
Mesenchymal polypoid proliferation
stromal spindle cells
small blood vessels,
inflammatory cells, particularly eosinophils.
middle aged females
inflammatory fibroid polyp
Risk factors for gastric adenocarcinoma:
- Chronic gastritis, H. pylori gastritis and autoimmune gastritis (intestinal metaplasia-dysplasia-carcinoma sequence).
- Dietary carcinogens (nitrosamines, smoked foods).
- Menetrier’s disease.
- Diets lacking in fruits/vegetables (antioxidants).
- familial adenomatosis polyposis (FAP).
can present as a polypoid invasive mass or invasive ulcer. Microscopically, tumor shows glandular differentiation.
Intestinal type gastric adenocarcinoma
involvement and thickening of the gastric wall (mucosa, submucosa, and muscularis propria).
signet-ring cells
involvement of the gastric wall
rigidity and a leather bottle appearance (linitis plastica).
Diffuse type gastric adenocarcinoma
Tumor that differentiates towards interstitial cells of Cajal:
GIST
Key genetic mutation of GIST tumors:
KIT tyrosine kinase
Tx for GIST:
Why?
imatinib (Gleevec)
tyrosine kinase inhibitor
Most common RF for MALT lymphoma?
H. pylori
Tx for MALT lymphoma:
antibiotics
Tumors from endocrine cells of GI tract:
carcinoid
**now called neuroendocrine
Test for neuroendocrine tumors:
24 hour urinary 5-hydroxyindoleacetic acid (5-HIAA), a metabolite of seratonin
inflammation of the thin, mesothelial covered layer of tissue that lines the abdominal cavity
peritonitis
Causes of peritonitis:
bacteria
bile
acute hemmorrhagic pancreatitis
foreign material
endometriosis
accumulation fo fluid in peritoneal cavity
ascites
By far most common cause of ascites:
cirrhosis –> portal hypertension
Common complication of ascites:
spontaneous bacterial peritonitis
Two types of ascites:
transudative (hypoalbuminemia, cirrhosis)
exudative (infection, malignancy)
Two most common causes of malignant ascites:
ovarian carcinoma
pancreatic carcinoma
a dense fibrosing process that can result in renal failure due to ureteral obstruction
idiopathic retroperitoneal fibrosis
foveolar hyperplasia
mucin depletion
vascular congestion
edema
lamina propria fibrosis
Chronic reactive gastropathy
