Physiology & Pharmacology: Fluid balance & motility in GIT.

Question 1

Define Diarrhoea

Answer 1

More than 500ml of faeacal output

Loss of fluid & solutes from GI tract .

Question 2

Absorption of water in GIT is active. T/F?

Absorption of water is driven by mainly which ion?

Answer 2

False- Passive

Na

Question 3

Na+ absorption in the small intestine occurs wvia which transporters?

Answer 3

1. Na+/glucose
2. Na+/amino acid co-transporter

Question 4

The commonest bacterial strain causing Gastroenteritis in UK?

Answer 4

Campylobacter Jejuni

Question 5

What are some other infectious causes of Diarrhoea?

Answer 5

Travellers Diarrhoea- E,coli, Salmonella, Shigella, Giardia

Question 6

Non inectious causes of Diarrhoea?

Question 7

What are the two pathophysiologies of diarrhoea?

Answer 7

1. Infectious toxins, bile salts, carcinoid tumours- Increase Cycliac AMP.
2. Rotavirus- Inhibition of Na/K/ATPase & structural damdage to mucosal cells–> Reduced absorption

Question 8

What are the systemic effects of Diarrhoea?

Answer 8

1. Dehydration
2. Metabolic acidosis
3. Hypokalaemia
4. Fatal if severe

Question 9

Most important asepct of managing diarrhoea is what?

Answer 9

Maintaing fluid & electrolyte balance.

Might also need antimicrobial agents, antimotility, spasmolytic agents in severe diarrhoea

Question 10

What is the management of Diarrhoea when fluid loss > 10% of body weight?

Answer 10

Oral Rehydration Therapy- IV rehydration.

Question 11

The SGLT1 transporter is used in Rehydration therapy why?

Answer 11

Increased uptake of glucose and sodium improves Water uptake by the body, improving fluid balance.

Question 12

Antimicrobials have a role only in severe diarrhoea. T/F?

Answer 12

True

Question 13

What are the common antibiotics used in severe diarrhoea? (4)

Answer 13

1. Cotrimoxazole
2. Erythromycin
3. Ciprofloxacin
4. Doxycycline

Question 14

What two antibiotics are used in C.Diff colitis?

Answer 14

1. Metronidazole
2. Vancomycin

Question 15

Anti-motility agents are used for symptomatic relief in what kind of Diarrhoea?

Answer 15

Idiopathic or mild travellers diarrhoea.

Contraindicated in

1. Acute infective diarrhoea
2. IBS/IBD
3. Diverticulosis

Question 16

What are the pharmacological effects of anti-motility agents?

Answer 16

1. Inhibiion of Enteric neurones
2. Decreased Peristalsis, Inceased Segmentation
3. Increased fluid absorption
4. Constriction of pyloric,ileocaeal, anal sphincters
5. Increased tone of large intestine

Question 17

Three main Anti-motiliy agents?

Answer 17

1. Loperamide
2. Diphenoxylate
3. Codeine

Loperamide- best cos= selective for GI, long acting, few side effects.

Question 18

Many Diphenoxylate preparations contain _.

Answer 18

Atropine.

Question 19

What is Constipation?

Answer 19

Infrequent production of hard stools needing straining to pass/incomplete shitting.