Heme/Onc Flashcards
Plummer-Vinson syndrome symptoms
Triad
Fe deficiency anemia
beefy red tongue
esophageal webs
What is methemoglobinemia
when Fe2+ iron oxidized to Fe3+ iron
cause of TTP
- symptoms/signs
- treatment
ADAMTS13 mutation
vWF not cleaved –> traps and activates platelets
Microangiopathic Hemolytic anemia (incr LDH, decr haptoglobin) with schistocytes
Thrombocytopenia
sometimes- renal failure, CNS, fever
plasma exchange
Glucocorticoids
Rituximab
explain one mechanism by which tumor cells can become resistant to chemotherapeutic agents
human multidrug resistance (MDR1) gene
- codes for P-glycoprotein, a transmembrane ATP-depedent efflux pump protein
- reduces drug influx into cytosol and increase efflux from cytosol
(similar mechanism by which many bacteria have developed resistance to abx)
how does methotrexatae work as a chemo agent
folic acid analog that inhibits dihydrofolate reductase
-> inhibits DNA synthesis
causes death of all rapidly dividing cells (esp in GI where can cause ulcers and in bone marrow where can cause pancytopenia)
features of CLL
smudge cells (Crushed Little Lymphocytes) CD5 and CD20 positive B-cells
age >60y
fear transformation to an aggressive lymphoma (most commonly diffuse large B-cell lymphoma)
features of ALL
most freq in children
assoc with Down syndrome
t(12;21) better prognosis, this transloc most common in kids
adults may have t(9;22) philadelphia transloc
TdT+, CD10+ (if it’s the B-cell form)
T cell form presents as mediastinal mass (thymus) and SVC-like syndrome
CD7+
most responsive to chemotherapy
however can mets to CNS and testes (poor chemo penetration) so must radiate/chemo these specially
features of Hairy Cell Leukemia
mature B-cell tumor
hair-like cytoplasm projections
dry tap on aspiraiton (causes marrow fibrosis)
present with massive splenomegaly (WBC fills red pulp)
stains TRAP+
treat with cladribine (similar structure as adenosine, highly toxic to hairy cells when taken up)
AML translocation
myelogenous so no cell surface markers
median onset 65y
incr circulation of myeloblasts
Auer rods
Myeloperoxidase cytoplasmic inclusinos
APML subtype has t(15;17) translocation, responds to vitamin A which induces differentiation of promyelocytes
DIC is a common presentation (MPO released from Auer rods)
CML translocation
-gene product?
older age
hallmark is philadelphia chromosome t(9;22)
BCR-ABLfusion gene -> constitutively active tyrosine kinase -> WBC avoid apoptosis and accumulate in blood
incr levels of all granulocytes (ie basophils, neutrophils, eosinophils)
splenomegaly
very low LAP distinguishes it from leukemoid reaction (incr neutrophils with infection) b/c CML neutrophils don’t have LAP
cause of multiple myeloma
- symptoms
- treatment and mechanism
neoplastic B cells mature into plasma cells that make large amounts of Immunoglobulin or Ig fragments
suseceptble to proteasome inhibitors (eg bortezomib, a boronic acid containing dipeptide). w/o proteasome, toxic amoutns of protein accumulate in cell –> apoptosis
how does mycoplasma pneumoniae infection lead to mild transient hemolytic anemia
mycoplasma pneumoniae binds an oligaosaccharide (I-antigen) on resp epithelium that is also present on rbc surface
this leads to formation of cross-reacting IgM antibodies (cold agglutinin) that attach to rbc, activate complement and cause eryhtrocyte lysis
what is purpose of heparin bridge to warfarin (ie overlapping coadminstration of heparin)
warfarin most quickly reduces levels of Protein C (short half life) causing a transient hypercoagulable state -> warfarin skin necrosis
by what 2 mechanisms does ionizing radiation treat/palliate cancer
causes cell death by
- DNA double strand breakage (break both bc single strand breaks readily repeaired by polymerases)
- free radical formation (from ionization of water; O2 free rad cause cell and DNA damage)
radiation effects most pronounced in malignant cells bc they are rapidly dividing and thus less able to repair DNA damage
cause of anemia in SLE
formation of warm IgG autoantibodies against erthyrocytes