H. Pylori Infection Flashcards
Describe helicobacter pylori.
Slow-growing Spiral Gram-negative Flagellate Urease producing
The majority of people infected with H. pylori are symptomatic
True/false
False
Majority are asymptomatic
How does H. pylori adhere to the epithelial surface?
Using adherence molecules such as BabA, which binds to the lewis antigen on the surface of gastric mucosal cells
How does H. pylori cause damage to epithelial cells?
The release of enzymes and induction of apoptosis through binding to class II MHC molecules
What are the results of H. pylori infection?
Inflammation (gastritis and gastric intestinal metaplasia)
Peptic ulcers
Gastric cancer
What is the usual effect of H. pylori?
Antral gastritis
What are the symptoms of antral gastritis?
Usually asymptomatic
Slight dyspepsia
When chronic, causes hypergastrinaemia, this increase in acid output can led to duodenal ulceration
What type of gastritis are gastric ulcers associated with?
Gastritis affecting the body and antrum, causing parietal cell loss and reduction in acid production
What is a peptic ulcer?
A break in the superficial epithelial cells penetrating to the muscularis mucosae
Has a fibrous base and increase in inflammatory cells
What is an erosion in peptic ulcer disease?
A superficial break in the mucosa alone
Which are more common, duodenal or gastric ulcers?
Duodenal
Which areas are gastric and duodenal ulcers most commonly found?
Gastric: lesser curvature of the stomach
Duodenal: duodenal cap, with inflamed, haemorrhage or friable surrounding mucosa
What are the symptoms of peptic ulcer disease?
Epigastric pain (recurrent, burning, highly localised)
May be relieved at night
Nausea may accompany pain
Vomiting may relieve pain
Anorexia and weight loss (particularly GUs)
Epigastric tenderness
In which contexts is diagnosis done for H. pylori infection?
Active PU disease
Previous PU disease
Mucosal-associated lymphoid tissue (MALT) lymphoma
To test and treat patients under 55 without alarm symptoms
What are the methods of investigation for H. pylori?
Serological tests 13C-urea breath test Stool antigen test Biopsy urease test Histology Culture
Which antibodies do serological tests detect for H. pylori?
IgG antibodies
When are serological tests helpful and unhelpful?
Helpful for diagnosis
Unhelpful for confirming eradication as IgGs take a long time to decline
When is a 13C-urea breath test helpful and unhelpful?
Helpful for screening
Less helpful when patient has taken antibiotics in the past 4 weeks or PPIs in the past 2 weeks
When is a stool antigen test helpful and unhelpful?
Used to determine H. pylori status and to monitor efficacy of eradication therapy
Less helpful if patient has taken PPIs in the past 2 weeks
What is investigation method is used in patients with refractory H. pylori to identify the appropriate antibiotic regimen?
Culture
What is the management when H. pylori is detected?
Eradication therapy
What are the regimens for H. pylori eradication?
Omeprazole 20mg + clarithromycin 500mg + amoxicillin 1g, all twice daily for 7-14 days
Omeprazole 20mg + metronidazole 400mg + clarithromycin 500mg, all twice daily for 7-14 days
What regimen is used for H. pylori eradication in eradication failure or areas of clarithromycin resistance?
Bismuth chelate 120mg x4 daily Metronidazole 400mg x3 daily Tetracycline 500mg x4 daily A PPI 20-40mg x2 daily All for 14 days
What are the complications of peptic ulcer disease?
Haemorrhage
Perforation
Gastric outlet obstruction
