Bariatric surgery & metabolism

Question 1

BMI for morbid obesity

Answer 1

greater than or equal to 40

Question 2

BMI for obesity

Answer 2

greater than or equal to 30

Question 3

BMI for overweight

Answer 3

greater than or equal to 25

Question 4

Banned by European medicines agency in ‘08 due to increased risk of serious psychiatric problems and suicidal tendencies

Answer 4

Rimonabant: CB1 receptor antagonist

Question 5

associated with unpleasant side effects such as loose, oily stools

Answer 5

orlistat: lipase inhibitor which reduces fat absoprtion

Question 6

approved but comes wth risk of psychiatric events & suicidial tendencies

Answer 6

Contrave: combination of naltrexone and bupropion

Question 7

like exenatide and used for chronically obese

Answer 7

Liraglutide: GLP-1 receptor antagonist

Question 8

conditions for bariatric surgery

Answer 8

• unable to lose weight through diet, exercise, pharmacotheraphy
• BMI greater than or equal to 40
• Obesity history of over 5 years

Question 9

how is bariatric surgery performed

Answer 9

laparoscopy - relatively non-invasive

Question 10

3 types of bariatric surgery

Answer 10

gastric band, gastric sleeve, gastric bypass

Question 11

gastric band

Answer 11

band with inflatable ballon inserted aroundupper stomach to create pouch. restricts passage of food to prolong fullness after eating
balloon size regualted by saline through subcutaneous port
Reversible

Question 12

which bariatric surgery is reversible

Answer 12

gastric band

Question 13

gastric sleeve

Answer 13

vertical sleeve of 200ml of up to 80% of the stomach.
food bypasses the stomach
food has normal passage down GI tract
excised portion is removed

Question 14

which bariatric surgery results in food bypassing most of stomach but has normal passage through GI

Answer 14

gastric sleeve

Question 15

gastric bypass

Answer 15

small pouch 15-30ml is sperated from stomach
this is then connected to lower jejunum
food passes stomach, duodenum and proximal jejunum
gastric remnant remians in situ, but doesnt come in contact with food

Question 16

mortality rate of gastric sleeve

Answer 16

0.1%

Question 17

mortality rate of gastric band

Answer 17

0.05%

Question 18

martality rate of gastric bypass

Answer 18

0.2%

Question 19

abropstion of what is reduced in all bariatric surgieries

Answer 19

calcium - leading to metabolic bone diseases & secondary hyperparathyroidism

Question 20

what defieicnes are sleeve and bypass patients at risk of

Answer 20

calcium, folate, iron, B1, B6 B12 and viatmin D

Question 21

how do bariatric surgeries promote weight loss

Answer 21

• reduce capacity of stomach therefore reducing food intake

- reducing the absorptive SA of GI tract, causing nutrient malabsorption

Question 22

unexpeted outcome of bariatric surgery

Answer 22

improvements in diabetes within weeks of surgery; not a consequence of weight loss

Question 23

how does gastric bypass improve T2DM

Answer 23

• food more rapidly delivered to L cells of distall GI 5 mins
• L cells rapidly secrete GLP-1 and PPY which are anorexigenic
• bypass of mucosal cells in lower stomach leads to lower grehlin secretions which is an orexigenic

Question 24

orexigenic peptide from lower stomach

Answer 24

ghrelin

Question 25

anorexigenic peptides from L cells

Answer 25

GLP-1 | PPY

Question 26

PPY

Answer 26

peptide secreted from L cells of distal GI reduced food intake & enhances inulsin stimulated glucose uptake anorexigenic

Question 27

how soon after gastric bypass to L cell peptide levels increase

Answer 27

within days and remain elevated for years

Question 28

how does gastric sleeve improve T2DM

Answer 28

more rapid delivery of food to K-cells of duodenum and L-cells of distal GI rapied secretion of GIP, GLP-1 and PPY which are anorexigenic

Question 29

how does gastric band improve T2DM

Answer 29

food is not rerouted and there is not change in GLP-1 or PPY levels BUT inflation of band is though to stimulate vagal afferent nerve fibres in the stomach these activate nuerons in the nucleus of the solitary tract this signalls to acruate nucleus to decrease appeite

Question 30

3 main mechanisms of weight loss and T2DM imporvements from bariatric surgeries

Answer 30

1. physical reduction in food intake and nutrient absorption 2. decreased food intake through central affects 3. increased insulin secretion & action

Question 31

what are the central affects of bariatric surgery that reduce food intake

Answer 31

- inreased anorexigenic signalling through PPY, GLP-1 - reduced orexigencie signalling through less ghrelin - increased vagal affernt signal to the ARC

Question 32

other non surgical methods of bariatic weight loss

Answer 32

- gastric ballons | - transpyloric shunt

Question 33

gastric balloon

Answer 33

two attached sillicone balloons placed in stomach through mouth filled with saline to restrict food intke - deaths following use

Question 34

transpyloric shunt

Answer 34

for bMI of 35-40 inserted to stomahc via mouth and expands in situ - high rates of adverse effects