GI: Diarrhoea

Question 1

What is Diarrhoea?

Answer 1

Passing of frequent watery or soft stools
* More than 3 per day

Can be life threatening if not treated
* Leads to chronic dehydration

Acute diarrhoea can be linked to infections (bacterial or viral)
* ‘Travellers diarrhoea’ (E-Coli)

Question 2

What types of infection cause diarrhoea?

Answer 2

1. Rotavirus
   * Damages small bowell villi
2. Invasive baceria
   * Damage epithelium layer
3. Campylobacter
   * Releases toxins which damage mucosa
4. Adhesive enterotoxigenic bacteria e.g. cholera
   * Adhere to brush border
   * Release cholera toxin (CT)
   * Activates Adenylyl cyclase
   * ^cAMP
   * ^Cl- and Na+ secretion, therefore inc water secretion

Question 3

What is the mechanism for cholera?

Answer 3

• • Pathogen gets into the GI tract, enters CT cells, replicates, multiplies, and then gets excreted to go on to infect other people

Question 4

How do you treat cholera?

Answer 4

1. Oral rehydration
2. Antibiotics
3. Orlistat - (blocks action of pancreatic lipase-stops fat bdown of fat in gut)
4. Misoprotosol - Used to treat ulcers
5. Cholera vaccine (oral)
6. Better sanitation and access to clean water

Question 5

What is oral rehydration?

Answer 5

• Solution of electrolytes, water and glucose
• Promotes Na re-uptake via symporter (water also reabsorbed)

Question 6

What are anti-motility drugs?

Answer 6

Opiates
* E.g. Morphine, codeine
* Loperaminde - First choice due to low side effects

Muscarinic receptor antagonist
* E.g. Atropine (low does)
* Inhibit post junctional muscarinic receptors

• Side effects include constipation

Question 7

What is Loperamide?

Answer 7

• Anti-motility drug
• Reduces tone and peristaltic movt of GI muscle wall
• Pre-symp inhibition

Question 8

What are absorbents?

Answer 8

• E.g. Kaolin, pectin etc
• Magnesium aluminium silcate
• Reduce impact of toxins
• Provide protective coating

Question 9

What are other treatments?

Answer 9

• Bismuth subsalicylate
• Short term relief
• Safe for children