MKSAP 2 Flashcards
Why tx outpatient PE with apixaban and not dabigatran
Dabigatran (direct thrombin inhibitor) requires bridging w/ parenteral therapy (5 days of heparin gtt vs. lovenox)
While apixaban doesn’t require bridge
Cryo helpful in hemophilia A, B, or both?
Cryo has factor VIII (deficient in hemophilia A), XIII, fibrinogen, and von willebrand factor
So cryo can be used in hemophilia A if individual recombinant factor unavailable
Main indications for cryo transfusion
DIC- cryo replaces fibrinogen, DIC is a state of hypofibrinogenemia (consuming clotting factors)
Other indications for hydroxyurea aside from sickle cell disease
Hydroxyurea = antimetabolite, can be used to reduce number of platelets in essential thrombocytopenia and RBCs in polycythemia vera
Describe type of disorders where you expect to see dense/hyperchromic RBCs vs. hypochromic RBCs on peripheral smear
Dense/hyperchromic RBCs = spherocytes in hereditary spherocytosis and autoimmune hemolytic anemia
Hypochromic (central pallor) RBCs from microcytic anemias like iron deficiency, thalassemias, sideoblastic anemia
Define
(a) Anistocytosis
(b) Poikilocytosis
(a) Anistocytosis = general term for RBCs of different sizes (high RDW)
(b) Poikilocytosis = term for RBCs of abnormal shape
Differentiate schistocytes and tear dropped shaped RBCs
Shistocytes (or helmet cells) = fragmented RBCs in intravascular hemolysis
Tear dropped cells from extramedullary hematopoesis seen in primary myelofibrosis or thalassemias
Tear drop shaped cells vs. bite cells
Tear drop RBCS are a marker of extramedullary hematopoesis seen in primary myelofibrosis or thalassemias
Bite cells- seen in hemolysis event in pt w/ G6PD deficiency
Why not test for G6PD deficiency during acute hemolysis reaction?
B/c G6PD enzyme is present at normal levels in new RBCs, then reduces by up to 75% as RBC lifespan proceeds. The older, more deficient, RBCS are destroyed first in a hemolysis event so if G6PD level measured then it will be falsely normal
74 y/oM w/ night sweats, found to have Hb 8.1. Normal Cr and calcium. Exam w/ splenomegaly, further bloodwork with IgM spike.
Most likely dx?
Anemia, B-symptoms, M-spike without kidney involvement. Get bone marrow biopsy to dx Waldenstroms macroglobulinemia = indolent B-cell lymphoma (lymphomatous infiltration causes lymphadenopathy and organomegaly)
Clonal bone marrow infiltrate that secretes IgM into blood
Best first diagnostic test for hereditary hemochromatosis
Serum ferritin and transferin sat (over 45% is typically the diagnostic cutoff) to dx iron overload
What is a DAAT for?
DAAT = direct antiglobulin antibody test, looks for IgG against RBC surface
test for warm autoimmune hemolytic anemia
What is warm agglutinin AIHA?
Warm agglutinin AIHA = autoimmune acquired hemolytic anemia where IgGs develop against RBC surface antigens that agluttinate at body temp (hence warm) causing RBC destruction
Why are spherocytes seen in AIHA?
B/c the IgG doesn’t allow it to be fully phagocytosed => reduced surface to volume ratio = spherocyte which then gets destroyed in the spleen
So igG medicated AIHA (warm AIHA) produces spherocytes
List some common causes of warm AIHA
Infection- viral (HIV, mono)
Drugs
lymphoid malignancies (seen in CLL)
Other autoimmune disorders (SLE, AI)
First line tx for stages I-III anorectal CA `
Both chemo and radiation, surgery only used as salvage therapy b/c need to remove sphincter
Chemo + rad is superior to radiation alone
Different than rectal (higher up, can often spare the sphincter) where options are surgery alone (stage I) vs. surgery/chemo/radiation (all three for full thickness stage II and lymph nodes stage III)
Typical clinical features of paroxysmal noctural hemoglubinuria (PNH)
Otherwise unexplained intermittent hemolytic anemia that presents w/ fatigue, jaundice, and intermittent red urine
Fatigue and abdominal pain often worse at times of higher hemolysis (urine more red)
How to diagnose/test for PNH
PNH = CD55/59 deficiency on RBC surface => test by flow cytometry for CD 55/59
Absence of CD55/59 (which normal prevents complement activation) => overdestruction/hemolysis of RBCs prematurely
24 y/oM p/w fatigue and intermittent dark urine, labs w/ pancytopenia
Dx?
PNH = paroxysmal nocturnal hemoglobinuria- CD55/59 deficiency (RBC surface protein that prevents complement activation)
Intermittent hemolysis- often p/w fatigue, abdominal pain, intermittent hematuria
Target Hb for sickle cell pt undergoing minor surgery
Simple transfusion to 10 improves surgical outcomes in sickle cell patients
(not exchange transfusion). Only use exchange transfusion for acute stroke, acute chest, retinal artery occlusion
Well’s score vs PERC criteria
Well’s score gives a pre-test probability of PE to help you decide d-dimer vs. CT PE
vs. PERC criteria is used as a rule out tool for low risk patients, if all criteria are NO, then no further testing (including d-dimer) is required
‘PERC out’
Coags (lab) finding most common in lupus anticoagulant
(a) Prone to bleeding or clots?
Lupus anticoagulant = acquired antibody to phospholipids.
Prolonged PTT that doesn’t improve with mixing w/ regular plasma (b/c Abs present still)
(a) Despite prolonged PTT in vitro, is associated w/ clots (not bleeding) in vivo
What is factor V leiden?
Factor V leiden = mutated factor V that is immune to the anticoagulant properties of protein C
=> higher risk of VTE
Explain how antithrombin deficiency (either genetic or acquired) can lead to heparin resistance
Heparin binds to antithrombin to inactivate thrombin, Xa, and other clotting factors => without antithrombin pt will be refractory to heparin (aka won’t see PTT prolong despite high dose of gtt)