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
Which ulcers perforate more often, gastric or duodenal?
Duodenal
What surgery is usually done for an ulcer that has perforated?
Laparoscopic surgery to close the perforation and drain the abdomen
What conservative management is done for the elderly and very sick with a perforated ulcer?
Nasogastric suction
IV fluids
Antibiotics
What are the causes of gastric outlet obstruction due to a peptic ulcer?
Active ulcer with surrounding oedema
Healing of an ulcer has produced scarring
What is the main symptom of gastric outlet obstruction, and why is this caused?
Vomiting
Stomach becomes full of gastric juice and ingested food, causing vomiting
What are the characteristics of vomiting produced by gastric outlet obstruction?
Without pain Infrequent Projectile Large in volume O/E there may be a succession splash Severe vomiting causes loss of acid from stomach and hypokalaemic metabolic alkalosis
How is diagnosis made for gastric outlet obstruction?
Endoscopy
What is the management for the vomiting caused by gastric outlet obstruction?
IV fluids and electrolyte replacement
Gastric drainage with nasogastric tube
Potent acid suppression
Endoscopic dilation of the pyloric sphincter or luminal stenting
What should be done if an ulcer is recurrent?
Check for H. pylori
Rule out Zollinger-Ellison syndrome
Exclude malignancy
What is ‘dumping’?
A number of abdominal symptoms (nausea and distension associated with sweating, faintness and palpitations) that are due to ‘dumping’ of fluid contents into the jejunum, causing rapid fluid shifts
What are the possible long term complications of surgical treatment?
Recurrent ulcer
Dumping
Diarrhoea
Nutritional complications
What are the possible nutritional complications that can result after gastric surgery?
Iron deficiency - due to poor absorption
Folate deficiency - due to poor intake
Vitamin B12 deficiency - due to intrinsic factor deficiency
Weight loss - due to reduced intake
What are some H. pylori associated diseases?
Gastric adenocarcinoma
Gastric B-cell lymphoma
What can long-term use of aspirin and other NSAIDs lead to?
Mucosal damage and ulceration
What is the management for NSAID-induced ulceration?
Stop NSAIDs
Give PPIs
Start eradication therapy if H. pylori positive
What is the management for NSAID-induced ulceration if stopping NSAIDs is not possible?
Use an NSAID with less GI side-effects at the lowest dose possible
If there is no CVD risk a COX-2 inhibitor can be used
Prophylactic cytoprotective therapy e.g. PPI or misoprosol
