IHL I - Bilirubin Metabolism and Platelet Function

Question 0

activity of aspirin?

Answer 0

inhibits platalet activity

through COX pathway (prostaglandins)

Question 1

petechiae

Answer 1

pinpoint hemorrhages under skin

subQ bleeds

Question 2

aspirin action of COX?

Answer 2

irreversible inhibition

due to acetylation of the enzyme

Question 3

COX activity?

Answer 3

catalyzes production of TXA2 in arachidonic acid pathway

TXA2 and ADP promote platelet recruitment and aggregation to form platelet plug

Question 4

TXA2

Answer 4

potent vasoconstrictor

Question 5

abciximab

Answer 5

inhibit the GPIIb/IIIa receptors on platelets

no platelet aggregation

Question 6

daibigatan

Answer 6

inhibits thrombin

Question 7

therapeutic use of aspirin

Answer 7

antiplatelet therapy

cardiovascular disease, angine, CAD, post-MI

Question 8

aspirin long term affects?

Answer 8

can develop a resistance to aspirin after a long time

variable among patients

Question 9

PTT

Answer 9

pro thromboplastin time

measures the intrinsic pathways

Question 10

Vit K requiring factors

Answer 10

2, 7, 9, 10

**liver disease - vit K goes down

Question 11

platelet function assays

Answer 11

can measure protein activity

Question 12

ristocetin cofactor assay

Answer 12

measure vWF activity

**ristocetin is an antibiotic leading to thrombocytopenia

induces platelet agglutination but only in the presence of vWF

Question 13

platelet aggregometry

Answer 13

checks for aggregation of platelets
-if they aggregate, they are functioning correctly

shine a light through sample
-if light visible through test tube you can identify aggregation

Question 14

hemophilia A

Answer 14

factor VIII deficiency

Question 15

hemophilia B

Answer 15

factor IX deficiency

Question 16

vWF deficiency

Answer 16

cant form platelet plug

also a decrease in factor VIII

Question 17

type O blood type and vWF?

Answer 17

have lowest levels

AB has highest

Question 18

purpura

Answer 18

subQ bleeding

Question 19

treatment of vWF

Answer 19

dDAVP (desmopressin nasal spray)

type I vWD treatment

stimulates release of endogenous vWF from endothelial cells

also for hemophilia A (bc vWF activates factor VIII)

Question 20

less at risk from thrombosis if vWF disease?

Answer 20

maybe

Question 21

normal range of bilirubin?

Answer 21

< 2 mg/dL

Question 22

source of bilirubin?

Answer 22

senescent RBCs broken down (120 days)

Question 23

main site of RBC breakdown?

Answer 23

occurs extravascularly

in the spleen

Question 24

heme oxygenase

Answer 24

breaks down heme to biliverdin

produces O2 and ferric iron (Fe3+)

requires NADPH

Question 25

conjugated bilirubin formation?

Answer 25

enzyme: UDP-GT

adds glucuronic acid (or xylose or ribose)

Question 26

stercobilin

Answer 26

oxidized from stercobilinogen in the large intestine

*presence of O2

Question 27

crigler najjar

Answer 27

deficient UDP-GT

increased levels of indirect bilirubin (very high)

death early age

Question 28

prehepatic jaundice

Answer 28

because of excess production of bilirubin following hemolysis

excess RBC lysis
Rh-ABO incompatibility
sickle cell disease

Question 29

intrahepatic jaundice

Answer 29

impaired uptake, conjugation, or secretion of bilirubin

reflects a generalized liver dysfunction

congenital: Gilbert’s, Crigler-Najjar, Dubin-Johnson, Rotor

Question 30

Posthepatic jaundice

Answer 30

obstruction of biliary tree

cholestasis

Question 31

intrahepatic cholestasis

Answer 31

failure of excretion at the cellular level

-due to swelling of hepatocytes and edema

Question 32

extrahepatic cholestasis

Answer 32

due to obstruction at any point in tract distal to the bile canaliculi

plasma bilirubin is conjugated
also pale-colored stool and dark urine

Question 33

autoimmune disease of prehepatic jaundice?

Answer 33

Rho incompatibility

Question 34

intrahepatic congenital diseases?

Answer 34

gilbert, crigler-najjar, dubin-johnson, rotor

Question 35

posthepatic jaundice?

Answer 35

extrahepatic bile duct blockage

ex/ gall stones

Question 36

direct coombs test

Answer 36

for incompatibility of blood tests

positive shows presence of antibody on blood cells

Question 37

phototherapy treatment?

Answer 37

converts trans to cis isomer

makes it more water soluble

Question 38

amylase and lipase

Answer 38

from the pancreas

elevated if problem in the pancreas