This site is 100% ad supported. Please add an exception to adblock for this site.

USMLE Secrets

Terms

undefined, object
copy deck
what does uremia do to the bone marrow?
makes it less responsive to EPO
what is hydroxyurea used for?
increases production of fetal hemoglobin HbF
what are Howell Jolly bodies?
inclusions of nuclear chromatin remnants seen in RBCs of pts with hypoactive splenic function
why should sickle cell patients consider prophylactice cholecystectomy?
70% of sickle cell patients develop symptomatic cholelithiasis
why does hepatosplenomegaly develop in thalassemia pts?
increased hemolysis of abnormal RBCs by macrophages in the spleen and liver; extramedullary hematopoiesis
where is dietary iron absorbed and in what form?
absorbed in proximal duodenum; we eat Fe+++ and absorb as Fe++
why do pts with chronic disease develop anemia?
1. chronic inflammation leads to more cytokines in blood and resulting increase in phagocytic activity destroying RBCs

2. cytokines inhibit renal secretion of EPO

3. lactoferrin released by inflammatory cells binds serum iron and makes it unavailable for erythropoiesis
what's the big picture problem in anemia of chronic disease and iron?
high iron stores, but unavailable to the body
what does B12 do?
1. catalyzes conversion of homocysteine to methionine

2. catalyzes conversion of methyltetrahydrofolate to tetrahydrofolate

3. converts methylmalonic acid to succinyl CoA
what is tetrahydrofolate?
form of folic acid used in DNA synthesis
what is G6PD?
the rate-limiting step in HMP pathway for NADPH production
what is glutathione?
after reduction by NADPH, it combats oxidatative damage in cells
what is primary hemostasis?
production of the temporary platelet plug
how does tPA work as a clot buster?
it's an enzyme that activates plasminogen, converting it to plasmin which cleaves fibrin strands
how does heparin work?
stimulates antithrombin III, which inhibits thrombin (factor II)
what is microangiopathic hemolytic anemia?
hemolytic anemia due to intravascular fracture of RBCs
E. coli 0157 and Shigella species are known for causing what heme dysfunction?
TTP or HUS
what's the main problem in TTP or HUS?
endothelial damage leads to platelet consumption
what does desmopressin acetate (DDAVP) do?
stimulates the liver to produce plasma clotting factors
what are 2 common causes of acquired platelet dysfunction?
uremia and NSAIDs
how do clopidogrel and ticlopidine work?
these 2 antiplatelet drugs block platelet-ADP receptor activation
how do abciximab, eptifibatide and tirofiban work?
inhibit platelet GpIIb-IIIa receptor which mediates aggregation via a "fibrinogen bridge"
what anticoagulant can cause thrombocytopenia?
heparin in 1-3% of pts;

can cause 2 syndromes:

HITS: heparin induced thrombocytopenia syndrome
HITT: heparin induced thrombocytopenia thrombosis
how can ITP be treated?
prednisone to slow the immune-mediated destruction of platelets

Deck Info

24

permalink