H. Pylori & Gastric Disease Flashcards by MLG .

What is Heliobacter Pylori?

A gram -ve, spiral shaped, microaerophilic, flagellated bacterium carried by around 50% of the worlds population

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Where does Heliobacter Pylori colonise?

Gastric mucosa

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How does Heliobacter Pylori cause a problem?

Ammonia and other chemicals

Damages epithelial lining

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What does a Heliobacter Pylori cause?

Chronic gastritis leading to:
- In most people no significant disease

If predominant in the body -> Loss of acid, gastric atrophy and finally gastric cancer
If predominantly in the antrum -> Rise in acid -> Duodenal ulcers

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What determines the outcome of a Heliobacter Pylori infection?

Site
Environmental factors e.g. smoking
Genetic susceptibility
Bug characteristics (virulence factors)

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Define virulence factors?

Molecules produced by certain strains of a micro organism which give it an advantage at colonising or harming the host.

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In what ways can we diagnose Heliobacter Pylori infection?

Non-Invasive:

Stool Antigen Test (ELISA)
Urea Breath Test
Serology (IgG test)

Invasive (by Upper GI endoscopy):

Staining of gastric biopsy
Culture of biopsy
Rapid slide urease test

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Explain the rapid slide urease test?

Biopsy of mucosa isplaced in a medium with urea and a pH indicator

> Urease converts urea to ammonia and CO2
pH rises
Indicator changes colour

Urease is an enzyme produced by Heliobacter Pylori

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Explain the Urea breath test?

Urea tagged with an unusual isotope of carbon is breathed in
Bacteria converts to ammonia + CO2
Unusual isotope of carbon detected in breathed out CO2

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What is the best invasive vs non-invasive way of detecting Heliobacter Pylori?

Stool Antigen Test (ELISA)

Rapid slide Urease Test

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How do we eradicate a Heliobacter Pylori infection?

7 days of triple therapy:

Clarithromycin
Amoxicillin (tetracycline if penicillin allergic)
A Proton Pump Inhibitor (PPI) e.g. Omeprazole

Further 2nd line protocols should this fail

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Define Dyspepsia?

Also known as indigestion.

A condition of impaired digestion causing symptoms such as:
- Upper abdominal pain/discomfort
- Anorexia
- Bloating
- Nausea / Vomiting
- Fullness and early satiety
- Heartburn
Retrosternal pain

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How common is dyspepsia?

Around 80% of people get it occasionally with no serious underlying disease

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Define a functional disorder?

One which impairs normal function of the gut without any detectable pathology.

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Define an organic disorder:

Any disease in which there is detectable pathology. Either micro or macroscopic

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Give some examples o dyspepsia causing conditions and whether they are functional or organic?

Functional:

Psychological (psychological factors are very important in many functional disorders)
Non-ulcer Dyspepsia
IBS
Drugs

Organic:

Peptic Ulcer
Gastritis
Gastric Cancer
Coeliac Disease
Colonic Cancer

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When would an upper GI endoscopy be indicated for dyspepsia?

If it came with any of the ALARMS symptoms:

Anorexia
Loss of Weight
Anaemia
Recent Onset >55 yrs or Persistant despite Treatment
Melaena/Haematemesis or Mass
Swallowing problems (Dysphagia/Odynophagia)

Define Haematemesis?

Vomiting blood

Define Odynophagia?

PAin when swallowing

NAme a few drugs that can cause dyspepsia

NSAIDs & Steroids
Ca Antagonists
Theophyllines
Nitrates

What is the flow chart approach to dyspepsia?

Dyspepsia:

Alarms features?
> Yes = Upper GI endoscopy
No = Age?
> Over 55 = UGIE
Under 55 = Heliobacter Pylori test
> If +ve do eradication therapy and or symptom treatent with antacids (PPIs or H2R antagonists) and change lifestyle factors

What are H2R antagonists?

Histamine H2 receptor antagonists

What lifestyle factors affect dyspepsia?

Smoking
Drinking
Diet
Lack of exercise

Loss of weight is an indicator

Define Gastritis

Inflammation in the gastric mucosa

How is gastritis diagnosed?

The clincal features can be seen on endoscopy then its confirmed histologically wiht a biopsy

What are the 3 typs of Gastritis?

A - Autoimmune (attacking parietal cells -> low HCl) B - Bacterial (Heliobacter Pylori) C - Chemical (Bile/NSAIDs)

What types of peptic ulcer are more common and with who?

Duodenal over gastric Men more than women Older more than younger

What can cause a peptic ulcer?

``` Heliobacter Pylori NSAIDs Smoking In rare cases: - Zollinger-Elison Syndrome - Hyperparathyroidism - Crohn's Disease ```

What are the symptoms of a peptic ulcer?

- Epigatric pain which may be relieved by antacids (point tenderness over diffuse) - Pain at night or when hungry (more often a DU) - Back Pain (may be a penetrating DU) - Nausea or vomiting - Weight loss/anorexia If it bleeds you might get haematemesis or melaena It often appears as just epigastric pain or tenderness

How is a peptic ulcer treated?

Antibiotics if its Heliobacter Pylori Antacids: - PPIs (omeprazole) - H2 receptor antagonist (ranitidine) Stop any NSAIDs Surgery - but only if complicated

Complications of a peptic ulcer?

Acute Bleeding: - Melaena - Haematemesis Chronic Bleeding: - Iron deficient anaemia Perforate Gastric outlet Obstruction: - Oedema - Fibrotic Stricture

What is gastric outlet obstruction?

Gastric outlet obstruction is not a single entity; it is the clinical and pathophysiological consequence of any disease process that produces a mechanical impediment to gastric emptying. Clinically it appears: - Vomiting, fermented foodstuffs not bile - Early Satiety - Abdominal Distension - Weight Loss - Gastric Splash - Dehydration - Loss of HCl in vomit -> Metabolic Alkalosis

What tests can we do for gastric outlet obstruction?

Bloods: - Low Cl, Na, K - Renal Impairment Upper GI endoscopy: - Prolonged Fast First or aspirate gastric contents - Then identify if its a stricture, ulcer or cancer

How do we treat gastric outlet obstruction?

Treat the underlying cause: - If its a stricture use Endoscopic Balloon Dilatation - Otherwise it often requires surgery

How common is gastric cancer and what histological types is it?

Second most common GI cancer 5 yr survival <20% Most are adenocarcinomas in the glandular epithelium. Can also be a lymphoma (MALT) or sarcoma (GIST)

MALT and GIST?

``` MALT = Mucosa Associated Lymphoid tissue GIST = GastroIntestinal Stromal Tumour ```

How do patients with gastric cancer present?

- Dyspepsia - Early Satiety - Nausea & Vomiting - Weight Loss - GI bleeding (haematemesis/Malaena) - Fe deficient anaemia - Gastric Outlet obstruction

Explain the aetiology of gastric cancer?

None of these are a direct cause but all are associated with gastric cancer: - Diet - Genes - Heliobacter Pylori - Smoking - Previous Gastric pathology or resection - Biliary Reflux - Family History

Explain the inheritance of gastric cancer?

- Most are actually sporadic with no demonstratable inherited component - <15% show familial clustering - 1-3% of cases are a heritable gastric cancer syndrome

How do we investigate a case of gastric cancer?

An upper GI endoscopy with biopsy to confirm using a histological diagnosis. Then stage with a chest and abdominla CT checking: - Lymph nodes - Lungs - Liver - Peritoneum - Marrow

How do we treat gastric cancer?

Surgery Chemotherapy DUH!

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H. Pylori & Gastric Disease Flashcards

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