Peptic Ulcer Disease and Acid Reflux Flashcards
What are the two functions of acid in our stomach?
- Break down food
- Sterilise unwanted microorganisms
What are the main functions of the oesophageal sphincter?
- Prevent air from entering the oesophagus during breathing
- Prevent reflux of stomach acid into the oesophagus
Why doesn’t the acid in the stomach digest the stomach itself?
Stomach epithelial cells produce mucus with bicarbonate that buffers the acid to prevent damage.
Describe the feedback loop of acid production in the stomach
In preparation for food, G-cells make gastrin. Gastrin stimulates parietal cells to secrete acid.
High acid concentrations act on D-cells to produce somatostatin. Somatostatin inhibits G-cells.
How can Helicobacter pylori impact the feedback loop of stomach acid production to cause ulcer formation?
H. pylori can suppress the production of somatostatin, and thus G-cells continue to produce gastrin - stimulating the production of acid.
H. pylori is located in the antrum of the stomach predominantly, and the increased acid production, along with inflammation of the stomach epithelium wears down the proective mucous layer, resulting in ulcer formation.
What is the cause of ulcerative oesophagitis?
Ulcerative oesophagitis is an inflammatory process caused by gastro-oesophageal reflux disease (GORD).
It is the MOST common reason why people take antacids.
What are the two main places in which peptic ulcers form?
Comment on their tendency to progress to malignancy.
Duodenum - almost ALWAYS benign
Gastric ulcers - can be cancerous
Can you carry Helicobacter pylori without having gastritis?
No. Despite 50% of the population having H. pylori, it cannot be carried without some degree of inflammation.
Does pepto-bismol kill helicobacter?
Yes - the bismuth in pepto-bismol has been shown to kill H. pylori and promote healing of ulcer.
What are the two drug-actions that must be administered to treat peptic ulcers?
Give an example of a treatment regimen.
Peptic ulcers must be treated with acid blocker + antibiotics.
Cure rate is low if the acid is not addressed.
Example: Omeaprazole (proton pump inhibitor) + amoxycillin + clarithromycin (ABX)
How do antacids function, giving an example.
What chemical compounds might you find in them?
Antacids work by reducing the acidity of your stomach contents.
They typically contain AlOH3, MgOH3, CaCO3.
A lot is required to heal ulcers. Generally, just used to treat acute reflux.
Example: Mylanta
What are drawbacks to using antacids?
Antacids can interfere with the absorption of drugs, such as antibiotics.
Furthermore, calcium + aluminium in antacids consitpate, while aluminium loosens stool.
How do coating agents function to help reflux?
Give an example
Coating agents float on top of stomach contents to prevent the reflux of acid.
Example: Gaviscon granules
How do mucosal protective agents work to protect against acid, giving two examples.
Thickens/strengthens mucus
Example: Sucralfate - Binds epithelial growth factor
Example: Bismuth - mixes with mucus to form insoluble bismuth oxide.
How do H2 receptor antagonists function?
Give examples:
ECL cells secrete histamine. Histamine acts on H2 receptors to induce acid secretion.
Antagonism of H2 receptor prevents acid secretion through competitive inhibition.
Examples end in -tidine: Cimetidine, Raniditine.
How do proton pump inhibitors function?
Give an example.
PPI’s inhibit H+/K+ ATPases to prevent secretion of acid.
They bind to -SH groups in the ATPases, inactivating them through non-competitive binding.
Example: Omeprazole (end in -prazole)
What are the epidemiological and healing times of duodenal vs gastric ulcers
Duodenal ulcers are more common in younger people, have high acid secretion and RELAPSE QUICKLY.
Gastric ulcers are more common in older people, and are much slower to heal.
What are three antibiotics used in treatment of ulcers which never cause resistance?
- Amoxicillin
- Bismuth
- Tetracycline
What does the BID PPI-based triple therapy for helicobacter infection involve?
- Omeprazole bid (PPI)
- AMoxicillin bid
- Clarithromycin bid
Produces 85% cure rate in 7 days.
