Bilirubin Metabolism and Excretion (Choudhury)

Question 1

UDPGT

Answer 1

adds glucuronides to uncon bilirubin to make it conjugated bilirubin ( in liver)

Question 2

majority of bile salts go where

Answer 2

recycled through enterohepatic circulation

Question 3

can indirect bilirubin flow through blood

Answer 3

no must be attached to carrier protein-albumin

Question 4

where does bilirubin get conjugated and by what

Answer 4

in liver by UDP-GT

Question 5

What happens to conjugated bilirubin in intestine

Answer 5

degraded by bacteria to make urobillinogen-> stercobilinogen

Question 6

What do you need to convert hemoglobin to unconj bilirubin?

Answer 6

O2(heme oxygenase) and NADPH(biliverdin reductase)

Question 7

where does heme come from

Answer 7

diet, myoglobin, p450 in mm cells, Hb

Question 8

where can you find heme oxygenase, and what does it do

Answer 8

phagocytes, kupffer cells, spleen and bone marrow cells. Converts heme into biliverdin

Question 9

Only place in body where we make CO

Answer 9

via heme oxygenase. production of biliverdin

Question 10

conditions that increase unconjugated or indirect bilirubin

Answer 10

hemolysis, Cirgler-Najjar syndromes, Gilbert syndrom, low levels of conjugation enzymes in newborn, hepatic damage

Question 11

Conjugated reacts quickly with what acid

Answer 11

diazosuluronic acid- azobilirubin

Question 12

Conditions that increase conjugated bilirubin

Answer 12

hepatic damage, bile duct obsturction (clay colored stool), dubin-johnson, and rotor syndrome

Question 13

abnormal levels of total bilirubin for jaundice

Answer 13

above 2 mg/dl

Question 14

cholestasis

Answer 14

impaired bile flow, increase conc of bilirubin, bile acids and cholesterol in blood

Question 15

kernicterus

Answer 15

[ ] of unconjugated bilirubin in newborn blood. when bilirubin enters CNS->mental retardation

Question 16

hemolytic anemia has what affect on liver

Answer 16

increase indirect bilirubin. seen in G6PD deficiency, PK deficiency and Vit K deficiency

Question 17

Crigler-Najjar

Answer 17

no UDP-GT- cannot conjugate bilirubin. sever congenital jaundice. death 6 mo-1 year

Question 18

Gilbert Syndromes

Answer 18

UDP-GT mutated(point). Indirect bilirubin levels slightly elevated- no jaundice unless stressed

Question 19

Kernicterus

Answer 19

newborns due to massive destruction of RBCs, and doesn’t respond to 2,3 BPG
or early birth and takes time for Hb to completely convert

Question 20

causes of direct bilirubin

Answer 20

intra or extrahepatic obstuction

defective canalicular transport

Question 21

Dubin-johnson

Answer 21

defective canalicular transport. black liver, brown urine

Question 22

Rotor Syndrome

Answer 22

asymptomatic direct hyper-bilirubinemia. problem of storage of bilirubin, so it leaks into blood,

Question 23

Causes that lead to increase both conj and unconj bilirubin

Answer 23

liver malfunction, cirrhosis, hepatic virus, Wilson’s-Cu disease

Question 24

main difference of type I and II circler-najjar

Answer 24

type I die in infancy. type II rare late onset of kernicterus with fasting

Question 25

alchol cirrhosis leads to

Answer 25

hyperbilirubinemia due to dec excretion of bilirubin into bile

Question 26

Prehaptic jaundice

Answer 26

excessive bilirubin presented.. can be caused by anemias. Inc serum unconj bilirubin

Question 27

Haptic causes of jaundice

Answer 27

abnormal hepatocyte function
enzyme mutation/impaired for hepatocellura upatake (unconjugated)
enzyme mutation/defective conjugation increase in unconj bilirubin
defective secretion of hepatocyte- increased conj bilirubin
hepatitis with lowered conjugation or excretion

Question 28

Post hepatic Jaundice

Answer 28

impaired excretion of bilirubin- mechanical obstruction of flow of bile into intestines
gall stones or tumors. increase serum and urine conjugated bilirubin and dec urobilin and stercobilin

Question 29

why are sulfonamides not give to infants less than 2 months

Answer 29

increase unconjugated bilirubin leading to kernicterus