GI Intro, Esophagitis, Gastritis, H. pylori

Question 1

describe GI tract colonization after birth

Answer 1

immediately after birth = E. coli and Streptococci

Question 2

describe GI tract colonization after breast feeding starts

Answer 2

breast fed =

E. coli, Streptococci, Bacteroides & Clostridium #s decline; Bifidobacterium #s remain high

Question 3

describe GI tract colonization if babies are formula fed

Answer 3

formula fed = Lactobacilli present

Question 4

describe GI tract composition at the begninng of weaning

Answer 4

beginning of weaning:

E.coli, Streptococci & Clostridium #s return to high levels

flora now similar to formula fed infants

Question 5

describe oesophagitis and name cases where it can occur

Answer 5

• oesophagitis = inflammation of the esophagus
  
  • odynophagia & dysphagia
• predominantly non-infectious (gastroesophageal reflux disease)
• infection: cancer chemotherapy, transplantation, HIV
  
  • prominent: Candida albicans, CMV, HSV

Question 6

describe esophagitis caused by Candida sp.

Answer 6

• diagnosis:
  
  • endoscopy; whitish plaques
  • double contrast oesophagram: discrete linear plaque-like lesions, upper-mid esophagus

Question 7

describe what is seen in the image

Answer 7

esophagitis caused by Candida spp.

Question 8

____ is the 2nd most common cause of esophagitis

Answer 8

HSV-1 is the 2nd most common cause of esophagitis

Question 9

describe the diagnosis of esophgitis caused by HSV-1

Answer 9

• diagnosis:
  
  • endoscopy/double contrast esophogram: multiple, small discrete, superficial ulcers (punctate, linear, stellate, or “volcano-like”)

Question 10

describe what is seen in the image

Answer 10

esophagitis caused by HSV-1

Question 11

esophagitis caused by ____ is increased in patients who had solid organ transplants

Answer 11

esophagitis caused by CMV is increased in patients who had solid organ transplants

Question 12

describe the diagnosis of esophagitis caused by CMV

Answer 12

• diagnosis:
  
  • endoscopy/double contrast esophagram: 1 or more giant (>10 cm), flat (ovoid, elongated or diamond shape) ulcers (sometimes with small satellite ulcers)

Question 13

describe what is seen in the image

Answer 13

esophagitis caused by CMV

Question 14

describe gastritis and name the causes

Answer 14

• gastritis = inflammation of stomach tissue with epigastric (sharp/burning) pain

Question 15

describe peptic ulcer disease (PUD)

Answer 15

• gastric & duodenal: lesions in mucosa in the stomach (gastric ulcers) or uppermost portion of small intestine (duodenal ulcers), presents with epigastric sharp/burning pain after eating
  
  • gastric ulcer = pain briefly after eating
  • duodenal ulcers = pain a few hours after eating
  • an endoscopy needed to differentiate

Question 16

compare gastric vs. duodenal ulcers

Answer 16

Question 17

describe the progression of gastric cancer

Answer 17

• progression:
  
  • chronic non-atrophic gastritis → atrophic gastritis → intestinal metaplasia → dysplasia
  • causes = multifactorial, H. pylori

Question 18

describe Helicobacter pylori (H. pylori)

Answer 18

• G-ve
• non spore-forming
• curved to spiral
• motile (5-6 polar flagella)
• catalase +ve, urease +ve

Question 19

H. pylori contains the enzyme urease which allows it to ____

Answer 19

H. pylori contains the enzyme urease which allows it to neutralize gastric acid and induce gastric mucosal injury by ammonia

Question 20

_____ allows H. pylori to adhere to host cells and causes inflammation

Answer 20

LPS allows H. pylori to adhere to host cells and causes inflammation

Question 21

describe the function of effectors in the pathogenicity of H. pylori

Answer 21

• effectors
  
  • actin remodeling
  • IL-8 induction, host cell growth, apoptosis inhibition

Question 22

the exotoxin produced by H. pylori is ____ which causes gastric mucosal injury

Answer 22

the exotoxin produced by H. pylori is vacuolating toxin (vacA) which causes gastric mucosal injury

Question 23

describe the most sensitive (non-invasive) test for diagnosing an H. pylori infection

Answer 23

• serology = most sensitive (non-invasive)
  
  • IgG antibodies
  • not useful for response to treatment

Question 24

describe a test to determine current infection (non-invasive)

Answer 24

• fecal antigen = determines current infxn (non-invasive)
  
  • specific, sensitive
  • used to check response to treatment

Question 25

describe the most specific test for diagnosing H. pylori infection

Answer 25

• gastric biopsy: most specific, requires endoscopy
  
  • look for presence of ulcers, cancer
  • histological changes, presence of H. pylori