bile

Question 1

what are the structures added in order to make bile acids more hydrophilic ?

Answer 1

taurine and glycine
makes it a better surfactant
one ned is hydrophobic and the other end is hydrophilic

Question 2

what is the hydrophobic portion of bile salts ?

Answer 2

choline

Question 3

what is the rate limiting enzyme for the classic pathway of bile acid formation ?

Answer 3

cholesterol alpha 7 hydroxylase
converts cholesterol into bile acid

Question 4

where does most lipid absorption happen ?

Answer 4

mostly in the jejeunum

Question 5

what are the functions of bile salts ?

Answer 5

emulsification of fats
excretion of cholesterol
antimicrobial

Question 6

what is the main mechanism of excretion of cholesterol by bile ?

Answer 6

conjugated bile is formed by the addition of taurine or glycine
making it water soluble
then excreted in the stool

Question 7

how do bile salts have an antimicrobial effect ?

Answer 7

disruption of bacterial cell membrane

Question 8

what is cholestasis and what are the lab findings ?

Answer 8

disrupted bile flow
direct hyperbilirubinemia
elevated ALP

Question 9

what are the symptoms of cholestasis ?

Answer 9

jaundice
pruritus
dark urine
clay colored stools

Question 10

where is ALP made and when does its level increase ?

Answer 10

bile duct epithelial cells
ALP levels increase whenever there is an obstruction of bile flow

Question 11

where does AST and ALT come from ?

Answer 11

these enzymes are found in the liver so any damage to the liver will cause an increase in the levels of these enzymes

Question 12

what is the difference in liver enzyme lab results when there is cholestasis vs when there is hepatocellular damage ?

Answer 12

cholestasis : a higher increase in ALP rather than AST/ALT (cholestatic patttern)
hepatocelllular damage : higher level of AST/ALT than ALP

Question 13

what is the first best test after lab tests for cholestasis identification ?

Answer 13

ultrasound

Question 14

what is the different workup used for intrahepatic vs extra hepatic causes of cholestasis ?

Answer 14

intrahepatic - lab tests and biopsy will be needed
extra hepatic - additional imaging

Question 15

what drug is associated with intra hepatic cholestasis ?

Answer 15

erythromycin

Question 16

what is the association between fat malabsorption and oxalate stones ?

Answer 16

oxalate usually binds to calcium
when there is a lack of bile absorption as with short bowel syndrome or with crohns
there is an excess of fats
which binds to calcium
leaving behind an abundance of oxalate to form kidney stones