Pathophys - Stomach

Question 1

Epidemiology of H. Pylori infection

Answer 1

The most common human bacterial infection
Over 50% of the world is infected
Risks include living in a developing country, crowded conditions, being older, and somehow experiencing the bacteria via oral-oral or fecal-oral route

Question 2

Pathophysiology of H. Pylori infection

Answer 2

Has several virulence factors that help it survive the harsh stomach acid. Has urease enzyme that produces ammonia, allowing it to raise the pH locally around itself.
It also imbeds itself in the gastric mucosa and colonizes surface epithelium. It causes inflammatory responses, leading to acute neutrophilic gastritis and chronic lymphocytic gastritis.
Usually non-pathogenic, but can cause peptic ulcers, atrophic gastritis and can lead to increased risk of gastric cancer and gastric lymphoma

Question 3

Treatment of H. Pylori infection

Answer 3

Triple therapy:

PPI + clarithromycin + amoxicllin for 10-14 days

If pt fails this therapy, then do quadruple therapy:

PPI + bismuth + tetracyclin + metronidazole

Question 4

What are the causes of gastritis

Answer 4

1. Infectious: most commonly with H. pylori infection. Found in immuncompromsied patients
2. Lymphocytic: Unknown causes with extensive lymphocytic infiltration of gastic wall
3. Eosinophilic: Infiltration of gastric wall
4. Gastritis associated with systemic disease: Crohns and sarcoidosis. AIDS patients are at risk with opportunisitic organisms such as CMV
5. Autoimmune Atrophic Gastritis: autommune attack against parietal cells, IF

Question 5

Describe peptic ulcer disease pathogenesis

Answer 5

Occurs when there is a failure of mucosal integrity and thus mucosal defenses are unable to protect the epithelium from the acid and proteases of the stomach

Can be caused by H. pyloir infection or from chronic NSAID use

Question 6

Explain peptic ulcer disease treatment

Answer 6

Treatment of acute bleeding: IV resuscitation to restore intravascular volume. Acid suppression via PPI drip. Surgery

Treatment of perforation: surgery

Question 7

What are the 5 most common types of gastric neoplasms

Answer 7

1. Gastric Polyps: Probably benign but has malignant potential. Common in familial polyposis syndromes. Associated with long term PPI use
2. Adenocarcinoma: Malignant, 2nd most common cancer in the world. Assocated with H. pylori. Poor prognosis
3. Stromal Tumors and GISTs: benign. Stain positive for c-KIT
4. Neuroendocrine/carcinoid: malignant, associated with syndromes of peptide secretion
5. Lymphoma: malignant, strong association with H. pylori