2: Physiology and pharmacology of fluid balance and motility Flashcards Preview

Gastrointestinal Week 5 2016/17 > 2: Physiology and pharmacology of fluid balance and motility > Flashcards

Flashcards in 2: Physiology and pharmacology of fluid balance and motility Deck (37)
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1

Diarrhoea is defined as the loss of at least ___mls of fluid per day from the GI tract.

500

2

Which ion does water follow into GI cells?

Na+

3

Water moves into GI tract cells by ___.

osmosis

4

Which transporter couples the influx of glucose and Na+ into enterocytes?

SGLT1

5

Apart from glucose, which other molecule is sodium ion influx  coupled to?

Amino acid influx

6

Which types of GI tract infection can cause diarrhoea?

Viral

Bacterial

Parasitic

7

What is the most common bacterium causing diarrhoea in the UK?

Campylobacter jejuni

8

Which bacterium most commonly causes Traveller's diarrhoea?

EnteroTOXIC E. coli

9

What non-infectious GI diseases can cause diarrhoea?

IBD

IBS

Lactase deficiency

10

Why does hyperthyroidism cause diarrhoea?

Increased motility

11

What infection can the use of broad spectrum antibiotics cause?

Clostridium difficile 

leads to colitis, diarrhoea

12

Increased levels of which molecules lead to increased expression of channels causing increased secretion into the gut?

cAMP

13

Toxins produced by infectious agents stimulate the enzyme ___ ___, which increase the levels of ____, which increases gut secretion causing diarrhoea.

adenylyl cyclase , cAMP/?cGMP

14

Diarrhoea can lead to ___ due to water loss.

dehydration

15

Diarrhoea can lead to ___ ___ due to bicarbonate loss.

metabolic acidosis

16

Diarrhoea can lead to ___ due to potassium loss.

hypokalaemia

17

Which disease, causing profuse watery diarrhoea, can be fatal if severe?

Cholera

18

What is the first line therapy for severe diarrhoea?

Fluid replacement (oral/IV)

19

Is coupled glucose/Na absorption affected by diarrhoea?

No - this is why fluid replacement therapy works

20

Which channel is used in rehydration therapy?

SGLT1

21

Why is salt solution used in rehydration therapy?

Takes advantage of coupled glucose/Na transport through SGLT1

And then water follows Na, causing rehydration

22

What do oral rehydration fluids contain?

Glucose

Sodium

to take advantage of SGLT1 ⇒ rehydration

23

Why are antibiotics used in a limited role in managing diarrhoea?

Most infections are VIRAL (rotavirus, norovirus)

Most bacterial infections are self-limiting so what's the point in using antibiotics

24

Antibiotics are useful in (self-limiting / severe) diarrhoea.

severe

25

Anti-motility agents (loperamide, opiates) are only used in (mild / severe) cases of diarrhoea.

mild

you want the mucosa and toxins to be flushed out of the system - anti-motility agents slow this down

26

Opioids cause ___ by decreasing the rate of peristalsis and constricting sphincters.

constipation

27

Does the body develop a tolerance to the constipating effects of opioids?

No

28

What are some anti-motility agents used in diarrhoea?

Loperamide (imodium)

Diphenoxylate

Codeine

29

Why is atropine added to the antimotility agent diphenoxylate?

Discourages abuse of diphenoxylate through side effects (nausea, headache, weakness, blurred vision)

30

What is constipation?

Production of hard stools requiring straining to pass

and/or

sense of incomplete defecation