Obesity + imaging abdo

Question 1

how is obesity measured

Answer 1

BMI >30
waist circumference >102 men, >85 women (linked to CVD)

Question 2

what are the different gut hormones

Answer 2

gut hormones regulate body weight using homeostatic/hedonic brain circuits that modify eating behaviour

orexigenic - only ghrelin
anxiogenic - leptin (adipocyte), CCK (SI I cells), gastrin (stomach G cells), bile acids (liver), insulin/amylin (pancreas)

short-term regulator = ghrelin (orixogenic), CCK
long-term regulator = insulin, leptin

Question 3

what are EEC enteroendocrine cells

Answer 3

present throughout GI tract
sense nutrients + release hormones with regulators (autocrine, paracrine, juxtacrine)

Question 4

how is energy homeostasis regulated in hypothalamus

Answer 4

in arcuate nucleus

accelerator neurons make APY (acts in brain to stimulate feeding)
also make AgRP that inhibits melanocortin receptors to prevent inhibition of feeding
accelerator neurons stimulated by ghrelin

brake neurons make melanocortin peptides that act on same area to inhibit feeding

Question 5

in low energy diet, what are the hormone levels

Answer 5

more ghrelin (stomach), GIP (SI K cells), pancreatic polypeptide (pancreas)
less PYY (LI L cells), CCK (SI I cells), insulin, amylin (pancreas)

Question 6

what is pathology of obesity

Answer 6

responsiveness of intestinal EEC (entero-endocrine cells) reduced
so blunted ghrelin post-meal + reduced diurnal variability (causes constant snacking)

leads to leptin resistance
reduced baseline/meal-stimulated levels of anoretic peptides (PYY, GLP1, GIP)

Question 7

what is metabolic syndrome

Answer 7

insulin resistance, HTN, hyperlipidaemia, obesity
increases risk of CVD

Question 8

what is obesity management

Answer 8

conservative: lifestyle changes (low cal diet, exercise), therapy to treat cause/trigger

medical: orlistat, GLP1 agonist

surgical - only if BMI 40+ or BMI 30-39 + comorbidity
adjustable gastric band
sleeve gastrectomy
roux-en-y gastric bypass

Question 9

what are 5Fs of distended abdo

Answer 9

fluid
faeces
flatulence - gas
fat
fetus

Question 10

what are 4Fs of gallstones

Answer 10

female
fat
fair
40+ yr

Question 11

when is abdo US done

Answer 11

to confirm ascites (+ assess cause)
guide drainage

Question 12

when is abdo US done

Answer 12

to confirm ascites (+ assess cause)
guide drainage

drainage not doe if abnormal clotting

Question 13

when is abdo US done

Answer 13

to confirm ascites (+ assess cause)
guide drainage (with seldinger technique)

drainage not doe if abnormal clotting

Question 14

what are causes of ascites

Answer 14

liver pathology:
portal vein thrombosis (Budd chiari syndrome - ascites, abdo pain, hepatomegaly)

pelvic mass
peritoneal/omentum deposits

Question 15

what imaging is done for flatus in abdo

Answer 15

initial AXR if suspecting obstruction
CT AP if likely obstruction

Question 16

if US has confirmed fluid and suspecting malignancy, what further imaging is done

Answer 16

CT for staging
MRI for characterisation