Gastrointestinal disease Flashcards by Emily Newland

What area of the GIT is affected by dyspepsia and what are the 4 main causes?

Symptoms effecting the upper GIT

Caused by underlying conditions, drugs, smooth muscle relaxants and gastric acid

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6 symptoms of dyspepsia

Retrosternal/epigastric pain 
Fullness 
Bloating 
Wind 
Heart burn 
Nausea/vomiting

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3 underlying conditions mistaken for dyspepsia

Peptic ulcer disease
Gastro oesophageal reflux disease
Non-ulcer dyspepsia

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6 drugs that can cause dyspepsia

Nitrates 
Theophyllines 
Bisphosphonates 
NSAIDs 
Corticosteroids 
Calcium antagonists

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Explain why smooth muscle relaxants cause dyspepsia

Cause smooth muscle of oesophageal sphincter to relax allowing stomach contents to rise up and come into contact with unprotected oesophagus

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Explain how gastric acid causes dyspepsia

Over production

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What cell is gastric acid secreted from and what type of acid is it

Parietal cells by proton pumps

Hydrochloric acid

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Name 4 drug groups used for gastric acid

Antacids
H2 receptor antagonists
Alginate preparations
Proton pump inhibitors

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3 chemicals that stimulate gastric acid secretion

Histamine
Acetylcholine
Gastrin

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What cell produces histamine?

Enterochromaffin like cells (ELC)

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What nerve is stimulated to release acetylcholine

Vagus nerve

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What cell is gastrin secreted by?

G cells

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Explain how gastric acid is secreted?

Gastrin, histamine and acetylcholine all stimulate proton pumps of parietal cells to transport hydrogen ions into the gastric lumen- in exchange for potassium ions.
Chloride and potassium ions passively diffuse out into the gastric lumen.
Gastrin and acetylcholine indirectly stimulate histamine release further stimulating gastric acid production.

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4 intrinsic GIT mucosa protective factors

Blood flow
Bicarbonate
Prostaglandins
Mucus

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3 aggravating intrinsic factors for GIT mucosa

Refluxed bile
Acid
Pepsin

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How do antacids work on dyspepsia symptomatic relief?

Neutralise stomach acid

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4 forms antacids come as

Tabs
Liquids
Single agents
Combinations

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2 interactions of antacids

Reduce absorption rate from GIT

Interfere with drugs that have enteric coatings

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4 ADRs of antacids

Constipation
Diarrhoea
Unpalatable
Alter sodium and aluminium absorption

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How do alginate preparations work?

Work as rafting agents, providing a protective coating of the oesophagus wen stomach contents rise up

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What condition are antacids used for?

Dyspepsia

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What 2 conditions are alginate preparations used for?

Gastro oesophageal reflux disease (GORD)

Dyspepsia

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True or false, alginate preparations are safe for use in pregnancy

True - minimal side effects

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What time of day are alginate preparations advised to be taken at?

Bed time or with evening meal

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2 contraindications for alginate preparations use and why

Hypertensive pts - sodium content of preparation | Diabetic pts - glucose content of preparations

How do H2 receptor antagonists work?

Inhibit histamine H2 receptors reducing production of stomach acid

What 2 conditions are H2 receptor antagonists used for?

Gastro oespophageal reflux disease | Peptic ulcer disease

True or false, H2 receptor antagonists and alginate preparations have few ADRs?

True

How do proton pump inhibitors work?

Inhibit the exchange of protons for potassium ions preventing the production of gastric acid.

What 3 conditions are proton pumps used for?

Gastro oesophageal reflux disease Peptic ulcer disease Dyspepsia

5 ADRs of proton pump inhibitors

``` GIT discomfort Headache Rash x2 increase in risk of C.Diff ? increased risk of osteoporosis ```

What bacteria causes chronic gastritis? | ?gram

Helicobacter pylori | Gram -ve

What % of duodenal ulcers are caused by helicobacter pylori infections?

95%

What % of gastric ulcers are caused by helicobacter pylori infections?

70-80%

What is the treatment for helicobacer infections?

Abx and a proton pump inhibitor

5 causes of gastro oesophageal reflux disease

Bile Acid Relaxation/dysfunction of lower oesophageal sphincter Motility dysfunction of lower oesophageal sphincter Life style factors

What 2 features of pregnancy increase the incidence of gastro oesophageal disease?

Increased abdominal pressure | Increased progesterone levels that causes smooth muscles to relax

What are the 3 stages of treatment for GORD in pregnancy?

1. Alginate preparation 2. H2 receptor antagonist 3. PPI

What is the treatment for GORD in an infant? And for what duration?

Alginate preparation for 1-2 weeks

What is the treatment for GORD in children and the duration?

H2 antagonist/PPI for 1 month

What is the aim of GORD treatment in adults?

To improve intrinsic factors (prostaglandins, blood flow, bicarbonate, mucus) that protect GIT mucosa and reduce contact of gastric acid with oesophagus

5 non-pharmacological lifestyle alterations to reduce GORD

``` Stop smoking Loose weight Avoid trigger foods e.g. fats Sleeping with head raised Avoid alcohol ```

What is the treatment for GORD in adults and duration?

PPI for 1-2 months, titrating down to the lowest dose to treat symptoms.

What are 2 reasons why pt would remain on max dose of PPI?

Severe GORD or strictures

7 causes of nausea / vomiting

``` Drugs Motion Endogenous toxins e.g. dialysis pt Over indulgence Viral infection Gastroenteritis Migraine ```

5 classes of anti-emetics

``` H1 receptor antagonists AchM receptor antagonists Anti-dopaminergics 5HT3 receptor antagonists Others- cannibinoids ```

What endogenous chemical do H1 receptor antagonists interfere with?

Histamine

What 3 conditions are H1 receptor antagonists most effective for?

Post op nausea and sickness Motion sickness Pregnancy sickness

2 ADRs of H1 receptor antagonists

Drowsiness | Antimuscarinic

What are AchM receptor antagonists most effective for?

Motion sickness

2 routes for AchM receptor antagonists

Transdermal patch | Sublingual tablet

3 ADRs of AchM receptor antagonists

Dry mouth Blurred vision Sedation

What are 2 subcategories of anti-dopaminergics?

Phenothiazines and butrophenones

How do phenothiazines work? | what area do they inhibit

Inhibit agents that stimulate the chemoreceptor trigger zone

What 2 situations are phenothiazines most effective in treating?

Post op nausea and vomiting | Palliative care nausea and vomiting

How do butyrophenones work? | which receptor do they inhibit where, GIT motility

Work as antagonists on dopamine receptors in chemoreceptor trigger zone. Increase GIT motility

What are butyrophenones most effective in treating?

Nausea and vomiting associated with chemotherapy

3 ADRs of anti-dopaminergics

Arrythmias Hyperolactinaemia Involuntary movements

Mechanism of how antiemetics work

Antagonists stopping propagation of action potentials from nausea/vomiting receptors

How do 5HT3 receptor antagonists work?

Inhibit receptors in the chemoreceptor trigger zone

What are 5HT3 receptor antagonists most effective in treating?

Chemotherapy related nausea/ vomiting | Post op nausea vomiting

What is an ADR of 5HT3 receptor antagonists?

Increase in arrythmias by increasing the QT interval

2 routes of administration for 5HT3 receptor antagonists

Orally | IV

Explain the mechanism of nausea/vomiting

Chemoreceptor trigger zone, located outside the blood brain barrier, able to detect noxious stimuli such as chemicals, ingested substances, endogenous toxins. Impulses pass from chemoreceptor trigger zone to vomiting centres in the ventricles of the brain. Vomit centre controls the smooth muscle of the stomach, when stimulated causing the stomach contents to be expelled.

Which structure detects motion sickness?

Vestibular apparatus

4 neurotransmitters involved in nausea/vomiting

Dopamine Histamine Acetylcholine 5 hydroxytriptamine

What neurotransmitter do D2 receptors bind to and where are they located?

Dopamine | Chemoreceptor trigger zone

What neurotransmitter do Ach Muscanaric receptors bind to and where are they located?

Acetylcholine | Vomiting centre and vestibular apparatus

What neurotransmitter binds to H1 receptors and where are they located?

Histamine | Vomiting centre and vestibular apparatus

What neurotransmitter binds to 5HT3 receptors and where are they located?

5 hydroxytripramine | Chemoreceptor trigger zone and in GIT

5 causes of constipation

``` Immobility Inadequate diet Lack of dietary fibre Drugs Disease ```

4 classes of laxatives

Osmotic Bulk Stimulants Softeners

Name type of bulk laxative and mechanism of effect

Ispagulahusk | Increases faecal mass, increasing the pressure on GIT wall stimulating peristalsis

What is an instruction for use in bulk laxatives?

Stay hydrated

Name type of osmotic laxative and mechanism of effect

Macrogols | Increase influx of water into faecal matter softening stool

2 ADRs of osmotic laxatives

Bloating | Flatulence

How do faecal softeners work?

Increase absorption of water into faecal matter decreasing surface tension

How do stimulant laxatives work?

Stimulate the gut wall increasing GIT motility

ADR of stimulant laxatives

Cramping

4 causes of diarrhoea

Infection Disease Drugs Diet

Treatment for diarrhoea

Fluid and electrolyte replacement, isotonic solution containing glucose, sodium, potassium, chloride and bicarbonate ions

What is the risk electrolyte wise in diarrhoea?

Risk of hypokalaemia caused by dehydration

Gastrointestinal disease Flashcards

Dyspepsia; Gastric acid secretion; Antacid; Alginate preparations; H2 receptor antagonists; Proton pump inhibitors; Gastro oesophageal reflux disease; Nausea and vomiting; H1 receptor antagonists; anti dopaminergics; 5HT3 receptor antagonists; Constipation; Laxatives; Diarrhoea (82 cards)