Module 2: H. pylori Covert

Question 1

H. Pylori Microbiology

Answer 1

-Spiral-shaped bacteria
-po-inflammatory to gastric mucosa
-all patients with PUD are tested for H. pylori

Question 2

H. pylori tests

Invasive

Answer 2

Invasive (endoscopy, a biopsy is taken from the area of the ulcer):
-Histology (95% sensitive)
-Culture
-Biopsy (rapid) Urease: most common - ammonia of H. pylori causes color change (90% sensitive)

Question 3

Why are Biopsy rapid Urease tests often preferred?

Answer 3

-Rapid results
-easy to perform
-90% sensitive
-but must hold PPI 1-2 weeks before testing

Question 4

Which of the invasive tests is impacted by PPI?

Answer 4

Biopsy (rapid) Urease
-hold 1-2 weeks prior to test
-may cause false negative results

Question 5

A test for H. pylori was ordered for a patient. The patient is currently not able to stop PPI treatment. Which H. pylori test should be performed?

Answer 5

-Histology (gold standard) -> microscope
-or Culture of biopsy
-disadvantage: delayed results

Question 6

H. pylori tests

Non-Invasive

Answer 6

-often outpatient
-Non-invasive

-Antibody detection: ELISA or IgG antibodies
-Urea-breath-test: H.pylori breaks down labeled C-urea -> exhale labeled CO2
-Fecal-Antigen (in the stool)

-> Hold PPI for 1-2 weeks prior to testing

Question 7

Which non-invasive test should be performed on a patient who is unable to stop the PPI treatment?

Answer 7

-Antibody detection: ELISA
-Antibody detection: IgG antibodies
-disadvantage: unable to differentiate between past and current infection

Question 8

H. pylori treatment regimen
Triple therapy

Answer 8

-no macrolide exposure
-clarithromycin resistance in the are < 15% (efficacy would drop to 20% if resistance is higher than 15%)

Non-PNC allergic:
-BID PPI
-Amoxicillin 1g po BID
-Clarithromycin 500 mg po BID
-14 days

PNC-allergic:
-BID PPI
-Metronidazole 500mg po TID
-Clarithromycin 500 mg po BID
-14 days

Question 9

H. pylori treatment regimen
Quadruple therapy

Answer 9

-patient with recent macrolide exposure or clarithromycin resistance is > 15%

-BID PPI
-Bismuth subsalicylate 525 mg po 4xd
-Metronidazole 250-500 mg po 3-4xd
-Tetracycline 500 mg po 4xd or Doxycycline 100 mg po BID
-10-14 days (10d possible bc higher efficacy with this regimen)

Question 10

What has to be done after H. pylori treatment?

Answer 10

Eradication confirmation
-via urea-breath-test, fecal-antigen-test or biopsy-based test

Question 11

When should an Eradication-confirmation test be performed?

Answer 11

-4 weeks after discontinuation of antibiotics
-1-2 weeks after discontinuation of PPI

Question 12

Which drug may cause metallic taste and disulfiram reactions?

Answer 12

Metronidazole

Question 13

Which drugs may cause N/V/D

Answer 13

-Clarithromycin
-Amoxicillin

Question 14

Counseling points for Doxycycline

Answer 14

-take with water: pill esophagitis
-photosensitivity
-avoid in pregnancy/pediatrics
-avoid cations: chelation

Question 15

Counseling points for Levofloxacin

Answer 15

-tendon rupture
-QTc prolongation
-blood suger dysregualtion
-altered mental status
-avoid cations

Question 16

Counseling points for Bismuth

Answer 16

-caution in ASA allergy, bc it contains a byproduct of aspirin
-black tongue and stool (black stool can be confused as a sign of a upper GI bleed)