Heme/Onc3 Flashcards
What is (the definition of) acute leukemia?
A neoplastic proliferation of blasts; defined as >20% blasts in the bone marrow
What is the general idea behind acute leukemia?
In acute leukemia, the idea is that there is a disruption in the ability of bone marrow cells to mature, so that the myeloblast, or the lymphoblast, for example, loses the ability to become a more mature cell. When this happens, the precursor cell (the blast) begins to pile up.
What are the two general categories of acute leukemia?
(1) Acute Lymphoblastic Leukemia
(2) Acute Myelogenous Leukemia
based on the phenotype of the blasts
What are the clinical and lab findings of acute leukemia?
Increased blasts crowd-out normal hematopoiesis, resulting in:
- -anemia (fatigue)
- -thrombocytopenia (bleeding)
- -leukopenia (infection)
Blasts enter the blood stream, resulting in a high WBC count
What do the blasts in acute leukemia look like on peripherla blood smear (or even bone marrow aspirate)?
(1) large
(2) immature (very little cytoplasm)
(3) punched out nucleoli
What is acute myelogenous leukemia?
A neoplastic accumulation of myeloblasts (>20%) in the bone marrow
By what stain can myeloblasts be characterized?
Positive cytoplasmic staining for myeloperoxidase (MPO)
What is a classic histologic finding of AML (particularly, the M3 subtype–acute promyelocytic leukemia)
Auer rods, which are crystal aggregates of MPO
What is the M3 subtype of AML?
acute promyelocytic leukemia
What is the M5 subtype of AML?
acute monocytic leukemia
What is the M7 subtype of AML?
acute megakaryocytic leukemia
What subtype of AML is characterized by a t(15;17) translocation? What is the translocation?
M3 - acute promyelocytic leukemia
This involves translocation of the retionic acid receptor (RAR) on chromosome 17 to chromosome 15.
RAR disruption blocks maturation and promyelocytes (blasts) accumulate.
With what genetic abnormality is acute promyelocytic leukemia (M3 subtype of AML) associated?
t(15;17) translocation
involves translocation of the retinoic acid receptor (RAR) on chromosome 17 to chromosome 15
A 35-yo woman comes to the physician because of several months of fatigue. Lab studies confirm the diagnosis of AML. She is placed on antileukemic therapy, but shortly after her first dose of chemotherapy, she develops brusing and bleeding, and she is diagnosed with DIC. What is the most likely subtype of AML in this patient? Why did she develop DIC?
M3.
This subtype of AML contains numerous Auer rods (granules), which are crystal aggregates of MPO. Auer rods can activate the coagulation cascade, leading to DIC.
Chemotherapeutic agents can trigger the release of these granules, leading to DIC.
How do you treat M3 AML?
with all-trans-retinoic acid (ATRA, a vitamin a derivative)
this binds to the altered recepter (RAR) and causes the blasts to mature to neutrophils (and eventually die)
What is acute monocytic leukemia?
a proliferation of monoblasts; the M5 subtype of AML
What is the classic presentation of the M5 subtype and why?
Patients will characteristically present with involvement of the gums; the blasts in M5 characteristically infiltrate the gums
What is acute megakaryoblastic leukemia?
a proliferation of megakaryoblasts; M7
What are the key associations in M7? (3)
- -associated with Down syndrome (usually arises before the age of 5)
- -these blasts lack MPO
- -associated with myelofibrosis due to PDGF release
In what disease would we see a monoclonal spike on electrophoresis and rouleaux formation of PBS (peripheral blood smear)?
Multiple myeloma.
multiple myeloma results from a malignant proliferation of plasma cells in the bone marrow. These neoplastic cells produce immunoglobulin (seen as an M spike on electrophoresis), which increases the serum protein. This increased serum protein decreases the charge between the RBCs–instead of spreading themselves out evenly across the smear, they pile up on each other like poker chips. This is known as a Rouleaux formation.
A 60 year old woman comes to the physician because of weakness, fatigue and bruising. Her pulse is 110/min, blood pressure is 100/75 mmHG, and RR is 22. Physical exam shows pallor and petechial hemorrhages in the mouth. Labs show marked increased in white cells, anemia, and thrombocytopenia. A peripheral blood smear shows blasts with auer rods. What complication is likely to occur upon lysis of these cells induced by chemotherapy?
DIC
What is the difference in outcome between normal Warfarin dosing and warfarin overdose?
Appropriate warfarin dosing will usually only prolong the PT, because only factor 7 levels are decreased enough to impair coagulation. (Only the extrinsic pathway is affected)
In warfarin overdose, both the PT and the PTT are prolonged because all of the vitamin K-dependent factors (2,7,9,10) are decreased. Here, both the intrinsic and extrinsic pathways are affected.