EXAM #1: PATHOLOGY OF THE STOMACH Flashcards
What is the definition of gastritis?
Acidic damage causing superficial inflammation of the gastric mucosa
What is the underlying cause of acute gastritis?
Imbalance of mucosal defenses and acidic environment
What are the three major mucosal defenses?
1) Mucin layer
2) Bicarbonate secretion
3) Normal blood supply
Normal blood supply delivers nutrients and removes acid*
What wall layer does acute gastritis NOT penetrate through?
Muscularis mucosa
What causes acute gastritis?
1) NSAIDs (esp Aspirin) b/c of decreased PGE2
2) Alcohol
3) Chemotherapy
4) Increased ICP–>vagal stimulation that increases acid production
5) Severe burns–>hypovolemia causing decreased blood flow
6) Shock–>decreased blood flow
Describe the morphology of mild acute gastritis.
- Hyperemia and edema
- Neutrophils above BM
Describe the morphology of severe acute gastritis.
Erosion of entire mucosal thickness and hemorrhage
What are the clinical features of acute gastritis?
Hematemesis*
Melena
*Especially in alcoholics
What is the definition of chronic gastritis? What does chronic gastritis lead to?
Chronic inflammatory changes of the gastric mucosa leading to:
- Mucosal atrophy
- Intestinal metaplasia
What at patients with chronic gastritis at risk for?
Progression to gastric carcinoma
What is the most common cause of Chronic Gastritis?
H. pylori
What are the characteristics of H. pylori?
Gram negative
Bacillus
S-shaped
Is H. pylori motile or non-motile?
Motile–contains a flagella
What enzyme allows H. pylori to survive in the gastric mucosa?
Urease
What allows H. pylori to bind to the epithelial surface of the stomach? What is the most common site of infection?
- Adhesins
- Antrum
What factors associated with H. pylori induce the production of cytokines?
CagA
VacA
These are proinflammatory peptides associated with some strains of H. pylori
There are divergent responses to H. pylori infection. When H. pylori causes disease, what is the most common outcome?
- Increased acid
- Increased gastrin
Leading to DUODENAL ULCER disease
What is the less common scenario that occurs with H. pylori infection?
- Decreased acid
- Increased gastrin
Leading to a high risk of GASTRIC CARCINOMA
What is autoimmune gastritis?
Gastritis that results from autoantibodies to parietal and IF cells
What are the consequences of IF antibodies?
Pernicious anemia and megaloblastic anemia (B12 deficiency)
What cancer are patients with autoimmune gastritis most at risk for?
Gastric carcinoma
What does achlorhydia distinguish between?
Autoimmune gastritis can lead to achlorhydia, H. pylori does NOT
Which primary cause of Chronic Gastritis can lead to Lymphoma and PUD?
H. pylori
Which primary cause of Chronic Gastritis can lead to Endocrine tumors?
Autoimmune gastritis
Structurally, what is the definition of an ulcer?
Involvement/ disruption of the muscularis mucosa
What are is the classic presentation of a gastric ulcer?
Epigastric pain that is worse with eating
How do you diagnose a gastric PUD?
1) Imaging
2) Endoscopy
Note that you need endoscopy for gastric ulcer, but NOT duodenal–these are NEVER cancerous
What is the most common cause of duodenal ulcers?
H. pylori (70%)
What are the proinflammatory cytokines induced by H. pylori will activate and recruit neutrophils?
IL-8
Note that this is especially seen with CagA and VacA
How does H.pylori induced gastric acid secretion effect the duodenum?
Increased gastric acid secretion leads to decreases duodenal bicarbonate (protection)
What is Zollinger-Ellison Syndrome?
Gastrinoma in the pancreas that drives HCl secretion in the stomach
What is the worst complication of an ulcer?
Perforated ulcer leading to:
1) Peritonitis
2) Sepsis
3) Death
Describe the morphology of a benign gastric ulcer. Where do these ulcers most commonly occur?
“Punched out” lesions along the Lesser Curvature (in the antrum)
What are the characteristics of a malignant gastric ulcer?
Irregular with raised borders
What is the major/ most common complication of PUD?
Bleeding
What is a stress ulcer?
Multiple ulcers seen in the face of shock
*Caused by decreased gastric blood flow
What is the morphologic feature of stress ulcers?
Multiple small ulcers
What is a Curling Ulcer?
Stress ulcer associated with extensive burns
Hypovolemia–>decreased blood flow
What is a Cushing Ulcer?
Increased ICP leads to stress ulcer formation
ICP–> increased vagal stimulation–>increased ACh release–>increased acid secretion
What is a Gastric Polyp?
Mass lesion in the stomach above the mucosa
What are the two major types of Gastric Polyps?
1) Hyperplastic or inflammatory polyp
2) Adenomatous polyps
What is a gastric carcinoma? What stage is gastric carcinoma when it is typically found?
Malignant proliferation of gastric surface epithelial cells
–>Late stage (poor prognosis)
What are the two major types of Gastric Carcinoma?
1) Intestinal
2) Diffuse
Describe the morphology of an intestinal-type gastric carcinoma.
- Large
- Irregular
- Heaped-up margins
Where are intestinal-type gastric carcinomas typically found?
Found in the antrum of the stomach along the lesser curvature
What are the major risk factors for gastric carcinoma?
1) H. pylori
2) Autoimmune gastritis
3) Nitrosamines in smoked foods (Japan)
4) Blood type A
Describe the morphology of a diffuse-type gastric carcinoma.
Signet ring cells that diffusely infiltrate the gastric wall
What is linitis plastica?
Desmoplasia–fibrosis– of the gastric wall in response to diffuse carcinoma that causes a THICKENING of the wall
How does gastric carcinoma typically present?
Late with:
- Weight loss
- Abdominal pain
- Anemia
- Early satiety
What is the prognosis for Gastric Carcinoma?
Poor–not found until late stage with less than 10% 5-year surivial
What is a Virchow node?
Involvement of the sentinel supraclavicular node with cancer
What is a Sister Mary Joseph nodule?
Gastric carcinoma to periumbilical area
What is a Krukenburg Tumor?
Metastatic diffuse-type gastric carcinoma to the ovaries
What is the Lymphoma associated with H. pylori infection?
MALToma
How is MALToma treated?
Treat the underlying H. pylori infection
What is a Gastrointestinal Stromal Tumor?
Neoplastic proliferation of mesenchymal cells i.e. “Cells of Cajal”
What is a Carcinoid Tumor?
Neoplastic proliferation of gastric neuroendocrine cells
What are GIST positive for?
c-KIT or CD117
What drug can be used to treat GIST?
Imatinib i.e. tyrosine kinase inhibitors