Peptic Ulcer Flashcards
what is an ulcer?
a deep break through the full thickness of the epithelium or mucosal surface
what are the characteristics of h. pylori?
a gram-negative spiral-shaped, flagellated, micro-aerophilic bacterium
where does h. pylori colonise? what are its effects?
- antrum of the stomach
- persistent low-grade inflammation, which can damage the epithelial lining and destroy the gastric mucosal barrier
- this promotes ulceration
how does h. pylori survive in the acidic environment of the stomach?
- produces the enzyme urease, which converts urea into water and ammonia
- the ammonia buffers hydrogen ions, raising the pH and allowing the bacterium to survive in the stomach’s acidic environment
what is the function of COX-1?
- catalyses the production of prostaglandins and thromboxane from arachidonic acid
- inhibition of COX-1 by NSAIDs can lead to gastritis + peptic ulcer disease (PUD)
what is the function of COX-2?
- catalyses the production of prostaglandins from arachidonic acid, which contributes to inflammation, pain, and fever
- NSAID inhibition of COX-2 reduces these effects
what are the risk factors for PUD?
- h. pylori
- NSAIDs
- SSRIs
- bisphosphonates
- smoking
- alcohol
- stress
what are the symptoms of PUD?
- epigastric pain
- dyspepsia
- heartburn
- nausea + vomiting
what is the investigation for PUD?
endoscopy
what is the urease (CLO) test?
- detects h. pylori by taking mucosal biopsies during endoscopy + placing them in a medium with phenol red and urea
- if urease is present, it splits urea, releasing ammonium and causing a pH-driven colour change
- the test may be falsely negative with PPI therapy
what is the urea breath test?
- the patient ingests ¹³C urea, which urease converts into ¹³CO₂, detected in the breath
- it is used for diagnosis + eradication testing
- patients must discontinue PPI therapy before testing to avoid false negatives
what is the stool antigen test?
- detects h. pylori antigens in faeces
- it is used for diagnosis + eradication testing
- patients must stop PPI therapy before testing to prevent false negatives
what is the first-line eradication therapy for h. pylori?
- 7 -day course of triple-therapy
- PPI
- amoxicillin*
- clarithromycin/metronidazole
what is the second-line eradication therapy for h. pylori?
quinolone/tetracycline
what is the management of PUD if h. pylori is negative?
4-8 weeks of full-dose PPI
why do gastric ulcers require follow-up endoscopy, but duodenal ulcers do not?
- gastric ulcers should be biopsied due to the risk of underlying malignancy
- should be reassessed after treatment with a follow-up endoscopy in 6–8 weeks to confirm healing
what are the long-term complications of PUD?
- gastric lymphoma/adenocarcinoma
- GOO
- perforation
- haemorrhage
