LO's (Non-Clic) Flashcards
Name the roles of acid in our body.
- Digestion of food
- Iron absorption
- Killing pathogens
Explain how the body has adapted to stomach acid.
▪ Mucous secreting cells
○ Trap bicarbonate ions ( creating an alkaline environment )
○ Creates gel like barrier which is an important protective layer
▪ Prostaglandins locally produced
○ Stimulate secretion of mucus and bicarbonate
○ Dilate mucosal blood vessel
○ Cytoprotective effect (this is where chemical compounds protect cells from harmful agents)
Name the cells that produce HCL.
▪ Parietal cells
What do parietal cells produce?
- HCL
- Intrinsic Factor
Name the cells that produce pepsinogen.
Chief / Peptic cells
What is another name for proton pump?
▪ K+H+ATPase
Describe the process of HCL secretion by the parietal cells.
- Water and carbon dioxide combine to form carbonic acid
- Carbonic Anhydrase breaks down the carbonic acid into its constituents (CO2, OH-, H+)
- H+ is pumped out into lumen of canaliculus, and K+ is pumped into the cell by the proton pump
- Bicarbonate from the carbonic acid constituents is then pumped out into interstitial fluid and chloride is pumped into the cell by Antiport
- Cl- then transported into the lumen by channels
- H+ and Cl- combine to form HCL
Name three endogenous secretagogues in the stomach.
▪ Gastrin (Polypeptide Hormone)
▪ Acetylcholine
- Histamine
a) What cells secrete gastrin?
b) Where are they found?
A) G Cells
B) Gastric antrum, duodenum
Describe the role of gastrin in acid production and digestion.
▪ Released into the blood
▪ Stimulates secretion of acid by parietal cells through the PP
▪ Increases pepsinogen secretion
▪ Stimulates blood flow and increases gastric motility
Describe the role of acetylcholine in acid secretion.
▪ Released from neurons
Stimulates muscarinic receptor on surface of parietal cells and histamine containing cells
Describe the role of histamine in acid secretion.
▪ Mast cells lying close to parietal cell release histamine
▪ Histamine release increased by gastrin and acetylcholine
▪ Acts on parietal cell H2 receptors
What percentage of the world population are infected with H.Pylori?
50%
A) H.Pylori is a causative factor in….
B) H.Pylori is a risk factor for…
C) H.Pylori has a strong link with….
A) Gastric and duodenal ulcers
B) Gastric cancer (adenocarcinoma)C) MALT Lymphoma
Other than peptic ulcers, name 4 conditions associated with Pylori.
▪ Dyspepsia
▪ Atrophic gastritis (gastritis leading to scarring and loss of glandular cells)
▪ Iron deficiency anaemia
▪ Idiopathic Thrombocytopenia Purpura
Describe the pathogenesis of a Helicobacter Pylori Infection.
1- Flagella acts as a corkscrew allowing it to invade the protective layers and cause damage directly
2- Produces urease enzyme which produces ammonia from water and urea which neutralises gastric acid
3- Ammonia itself has a local damaging effect
4- Neutral environment (increased pH) allows the Pylori to colonise and proliferate so more ammonia
5- Leads to damage of the protective mechanisms of the mucosa
6- Increases susceptibility of damaged mucosa to the acidic environment where there is inflammation (neutrophils and inflammatory cells, with marked persistent lymphocyte penetration) and cell death
List the symptoms of an acute infection of H.Pylori (usually when this occurs the symptoms are associated with something else like gastritis etc… - but this is where the damage is being caused and where it may lead to chronic infection).
▪ Nausea
▪ Dyspepsia
▪ Malaise
▪ Halitosis
Name three factors that make it more likely to develop H.Pylori chronic infection.
▪ Smoking
▪ Heavy alcohol drinking
▪ Older
▪ Male
Name three pieces of lifestyle advice you may give a patient with GORD/Dyspepsia.
▪ Healthy eating (lower bmi is better) ▪ Weight reduction ▪ Smoking cessation ▪ Lift the head of the bed ▪ Eat within 3-4 hours before bed, and eat small frequent meals
Name 4 precipitants of GORD/dyspepsia.
▪ Alcohol
▪ Coffee
▪ Chocolate
▪ Fatty foods
A patient presents with GORD/Dyspepsia. Part of the management you advice the patient regarding lifestyle changes which he informs you they have tried yet the symptoms persisted. Describe other management options at this point.
▪ Stop NSAID’s if possible
▪ Over counter remedies:
▪ Antacids (directly neutralise acid + inhibit activity of peptic enzymes - constitute salts of magnesium and aluminium) - Example: Maalox
▪ Alignates - taken in combo with antacid (usually have antacids in them), increase viscosity and adherence of mucus to oesophageal mucosa and forms a gel layer on the top of the stomach contents which prevents constituents from irritating the oesophagus - Example: Gaviscon
▪ Simeticone - antifoaming agent (helps bloating, flatulence) - Example: Infacol
▪ Consider H.Pylori testing
What are the possible tests for H.Pylori?
▪ Urea breath test - tests for the bacteria, and can tell if it has been eardicated (give labelled urea in capsule, if there is urease then the urea will break down to ammonia and CO2 which are also labelled, the CO2 will travel through blood and be exhaled in the breath test)
▪ Stool antigen
▪ Rapid urease test (biopsy based diagnostic test, done when an endoscopy is needed)
A) Describe first-line treatment of Patients who are H.Pylori positive following testing.
B) What if allergic to penicillin?
C) If they had previous exposure to clarithromycin? (just because the more you use it the higher the risk of resistance developing)
A) 7-day twice daily course of treatment with PPI + Amoxicillin and either clarithromycin or metronidazole
B) PPI + clarithromycin + metronidazole
C) PPI + Bismuth + metronidazole + tetracycline
Name 3 PPI’s.
▪ Omeprazole
▪ Lansoprazole
▪ Esomeprazole
List the conditions where PPI’s are used.
▪ Ulcer disease
▪ Reflux oesophagitis
▪ One component of H.Pylori eradication
▪ Zollinger-Ellison Syndrome (tumours called gastrinomas in the duodenum and pancreas lead to increased secretion of gastrin which leads to the increased secretion of acid)
Describe the mechanism of action of PPI’s.
▪ Block the K+H+ATPase (proton pump) of gastric parietal cells
▪ Reduces gastric acid secretion
▪ Example: omeprazole irreversibly inhibits the PP
▪ Usually oral administration
A) Name 3 side effects of PPIs. (they are rare which is why people stay on these drugs for long time which risks masking other serious conditions).
B) What is the danger of staying on PPI’s for a long time if they don’t usually cause harm?
A)
▪ GI symptoms (diarrhea, constipation, abdo pain)
▪ Headaches
▪ Rashes
B)
▪ May mask the symptoms of gastric cancer
▪ May increase GI infections
Describe the pathophysiology of Peptic ulcers.
▪ Can be associated with infection of mucosa with H.Pylori
▪ Due to imbalance between mucosal damaging factors (acid, pepsin) and mucosal protecting factors (mucus, bicarbonate, prostaglandins, nitric oxide)
List the symptoms of peptic ulcer disease.
▪ Burning gastric pain which may be partially relieved by antacids and related to meal times
▪ DU pain - worse a night and when hungry
▪ Nausea
▪ Heartburn
▪ Flatulence
▪ Perforation/haemorrhage/bleeding
A) Once you confirmed that there is a peptic ulcer due to symptoms and endoscopy, what do you do next?
B) What if the peptic ulcer disease is NSAID associated?
C) What if the patient is Pylori negative, and no NSAID association?
A)
▪ PPI or H receptor antagonist therapy; or
▪ H.Pylori testing and eradication if the patient is positive
▪ (offer endscopy and H.pylori re-testing 6-8 weeks after initiating treatment)
B)
▪ Stop NSAIDs if possible
▪ Offer full dose of PPI or H2RA for 8 weeks
▪ If Pylori present, subsequently offer eradication therapy
C)
▪ PPI OR H2RA For 4-8 weeks
A) What is Histamine H2 receptor antagonists used for?
B) Descrine H2RA MoA.
C) Give examples of H2RA.
D)
A)
▪ Peptic ulcers
Reflux oesophagitis
B)
▪ Competitive inhibition of H2 receptors
▪ Inhibits histamine, gastrin, and acetylcholine stimulated acid production
Pepsin secretion falls -> reduced volume of gastric juice
C)
▪ Ranitidine
▪ Cimetidine
(oral, low dose available over counter)
D)
▪ Diarrhoea
▪ Constipation
- Dizziness
Name possible complications of cimetidine.
▪ Interacts with androgen receptors leading to gynaecomastia in men and decreased sexual function
▪ Inhibits cytochrome P450 slowing down the metabolism of a range of drugs including anticoaglulatns and tricyclics
Can cause confusion in the elderly
List 4 potential causes of an unhealed ulcer.
▪ Non-adherence to treatment plan
▪ Malignancy
▪ Inadvertent NSAID use
Failure to detect H.Pylori
List 4 potential causes of an unhealed ulcer.
▪ Non-adherence to treatment plan
▪ Malignancy
▪ Inadvertent NSAID use
Failure to detect H.Pylori
Describe the different views on whose job is it to ensure that we lead healthy lives (legislation and policy regarding health)?
- View spectrum
- Libertarian view = authority should be limited to ensure that members of populations enjoy natural rights - this views that the role of the state is not population welfare
- Collectivist views = utilitarian view - maximisation of utility for the population as whole should be achieved by achieving the greatest collective benefit so the well fare of some may be sacrificed if it is in the benefit of the collective
- Liberal = many states have this view now, certain individual rights should be held but also care for the individual well fare (People argue this is very paternalistic)
A) What is hiatus hernia?
B) List risk factors for hiatus hernia.
C) Describe treatment of hiatus hernia.
A) Part of the stomach pushes/slides through the hole in the diaphragm in the lower part of the chest -> compression of stomach -> acid comes up the sphincter
B) over 50, obesity, smoking
C) Symptomatic as it usually requires no intervention, weight loss, smaller meals, surgery if really bad with food coming back up and dysphagia
