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)
Pt w/ transfusion-dependent MDS develops worsening fatigue, Hb stable but ferritin 1850.
Next step in tx?
Once ferritin is over 1,000 an iron chelator is indicated
Deferasirox (PO)
Deforoxamine (IV)
F w/ newly diagnosed metastatic lung adenocarcinoma- next steps to determine tx?
Mutation testing for non-small cell lung cancers to determine first line tx.
Specifically for EGFR mutations, ROS1 mutations, and ALK translocation
EGFR mutation- first line Erlotinib
ALK/ROS- first line Crizotinib
Erlotinib vs. crizotinib for non-squamous cell lung cancer
Erlotinib- use for NSCLC with EGFR mutations
-also first line for pancreatic cancer
Crizotinib- oral med for ROS-1 and ALK mutation positive NSCLC
Pt on R-CHOP develops neutropenic fever, what to do during next chemo cycle to reduce risk of recurrence
G-CSF 2 days into next cycle, to prevent neutropenia which is at highest risk 5-15 days after cycle
(answer is not to dose reduce the chemo)
For AIHA w/ symptomatic Hb 5, but cross-match incompatible, best strategy for transfusion?
Just use same type but cross-match incompatible b/c RBCs won’t last as long but will hopefully last long enough for immunsuppressants (steroids) to kick in
- not plasma exchange b/c it doesn’t remove IgG
- don’t withhold transfusion until find a compatible one b/c may never find a compatible one and need to tx symptoms
Genetic condition that increases risk of warfarin-induced skin necrosis
Protein C/S deficiency
Transient hypercoagulable state during initial 50% reduction of protein C activity when warfarin is initiated => when baseline deficiency increases risk of transient hypercoagulability => arterial clots => retiform purpura seen in warfarin-induced necrosis
What level of fibrinogen is an indication for transfusion?
(a) Transfusion of what?
Fibrinogen under 100 w/ active bleeding- transfuse (a) cryoprecipitate to replace fibrinogen (has higher fibrinogen than FFP)
What factor level may be conceptually helpful in differentiating coagulopathy of liver disease and DIC
They can look the same- low fibrinogen (under 100 necessitating cryo transfusion)
Prolonged PT/PTTs
but factor VIII actually is ironically elevated in liver disease b/c required liver-synthesized factor to clear it
Differentiate electrophoresis patterns for alpha-thal trait and beta-thal minor
4 alpha globin genes (alpha-thal due to deletions), 2 beta globin genes (beta thal due to mutation or deletion) Alpha trait (a-,a- or aa,--): normal HbA, A2, and F (normal Hb electrophoresis)
while beta-thal minor (BB+ or B0) has low HbA (a2b2), more HbA2 (a2d2) b/c of defective beta-gene
CBC factor that can differentiate iron deficiency anemia from thalassemia
Both are microcytic anemias- but RDW (anisopoiliolocytosis) higher/abnormal in iron deficiency, while RDW is normal in thalassemias b/c all are uniformly small/dense/nucleated RBCs
Chronic management (supplement) for alpha and beta thalassemias
Folate supplementation, but no iron! and no transfusions (unless 7 or bleedgin). Avoid supplemental iron b/c side effects of overload
Components of a hemoglobin molecule
HbA vs. A2 vs. F
HbA = alpha2beta2 HbA2 = alpha2delta2 HbF = alpha2gamma2
4 alpha genes, 2 betagenes
What is hemoglobin H?
Hemoglobin H = tetramers of beta-globin
in pts w/ only one copy of alpha globin gene (while normal is 4)
Copies of alpha globin gene: 4- normal 3- asymptomatic carrier 2- alpha thal trait 1- hemoglobin H disease 0- intrauterine demise
Can you be asymptomatic from just one deleted copy of alpha-globin gene for hemoglobin?
Yes! aa, aa- will have normal HbA (alpha2beta2)
What does HELLP syndrome stand for?
Hemolysis, elevated liver enzymes, and low platelets
What is hemoglobin E disease?
Hemoglobin E disease = point mutation in beta-globin gene, makes its own hemoglobin (alpha2, beta-mutated globin gene)
migrates separately on electrophoresis
Differentiate hemoglobin electrophoresis for sickle cell disease vs. sick cell trait
Sickle cell disease: both beta globin genes are mutated => over 90% HbS, tiny percent HbF in adults potentially
Sickle cell trait: only one beta globin gene has mutation => about 30% HbS (variable), lots of HbA still
First line antiepileptic after benzos for status epilepticus
Status epilepticus: immediately give benzos (ativan if have IV access, versed if need IM)
Then first line antiepileptic is choice of: keppra (levetiracetam) or fosphenytoin/phenytoin (fosphenytoin is the prodrug)
Medication adjust for tx of vascular dementia
Vascular dementia- treat reversible risk factors like obesity, HTN, AFib etc
Then donepazil used off label (acetylcholinesterase inhibitor)
What malignancy is associated with NMDA encephalitis?
50% of females over 18 yoa w/ NMDA encephalitis found to have ovarian teratoma => get CT A/P and transvaginal ultrasound
How long after onset of headache for subarachnoid hemorrhage is lumbar puncture helpful for diagnosis?
RBCs rapidly lyse upon entering the CSF- present in ~2-4 hrs after SAH starts
Then 12+ hours after- highest yield for xanthrochromia (yellow CSF) b/c RBCS break down into bilirubin
Pathogenesis of Parkinsons disease
Progressive loss of dopamine-producing neurons in the substantia nigra
What is the pull back test for Parkinsons and what does it indicate?
Pull back test- pull back on patient’s shoulders. Considered positive if they fall back onto you or take 2 or more corrective steps.
Best predictive factor for falls in Parkinsons
First line treatment for Parkinsons
(a) Age under 65
(b) Age over 65
Parkinsons treatment- disease is caused by loss of dopamine producing neurons on substantia nigra => want to replace dopamine
(a) Under 65: use dopamine agonists = carbegoline, ropinirole
(b) Over 65 or for younger once agonists stop being effective- use dopamine precursor = levodopa
To reduce overall dose-exposure to levodopa and delay levodopa-related complications
Mechanism of carbidopa/levodopa
Levodopa = dopamine precursor
Carbidopa = peripheral decarboxylase inhibitor to inhibit peripheral levodopa breakdown into active form => more active form available to cross BBB into CNS