Heme Onc 1 Flashcards
If a patient presents with atrophic glossitis, shuffling broad based gait, and loss of vibration/position sense with a peripheral blood smear demonstrating macroovalocytes, megaloblasts, and hypersegmented neutrophils then the most likely Dx is?
B12 deficiency»_space; pernicious anemia.
How can you differentiate a case of CML vs leukemoid rxn?
LAP (leukocyte alkaline phosphatase) score would be lower in CML because the neutrophils are cytochemically and functionally abnormal.
Why should you always rule out B12 (cobalamin) deficiency before starting folate supplementation?
Because B12 and folate act as cofactors for converting homocysteine to methionine in forming hemoglobin. B12 is also used in other processes, so if you give folate back you can end up depleting your limited B12.
B12 deficiency presents as peripheral neuropathy or posterior column defects due to defective myelin synthesis.
What is the relationship of transferrin saturation to TIBC and serum iron levels?
Transferrin saturation = serum iron/TIBC
What would you give to avoid/treat severe hypocalcemia following massive blood transfusions?
Calcium gluconate infusion
What is the MOA of febrile nonhemolytic transfusion rxn?
Most common adverse rxn within 1-6 hrs of transfusion. When RBC and plasma are separated from whole blood, small amounts of residual plasma and leukocyte debris remain in the red cell concentrate and these leukocytes release cytokines during storage»_space; transient fever, chill, and malaise during transfusion.
What role does Vit B6 (pyridoxine) play in preventing blood clots due to elevated homocysteine levels?
^ Homocysteine predisposes to venous thrombosis/atherosclerosis due to direct vascular damage, clotting factor activation, and blocking antithrombotic pathways. B6 lowers homocysteine levels by acting as a cofactor for cystathionine B-synthase which metabolizes homocysteine to cystathionine.
What disease should be suspected in pt who develop acute hemolysis after taking primaquine or sulfa drugs?
G6PD Deficiency.
Clinical manifestations: dark urine (Hb ^), pallor/fatigue (anemia), abdominal/back pain (severe hemolysis).
Lab results: Low Hb, ^ indirect bilirubin, ^ LDH, and decreased haptoglobin.
Heparin induced thrombocytopenia (HIT) is due to autoantibodies to:
PFF4 complexed with heparin. Characterized by thrombocytopenia, arterial or venous thrombosis, and necrotic skin lesions at heparin injection site within 5-10 days of starting therapy.
What’s the MOA behind paroxysmal nocturnal hemoglobinuria?
PNH is due to acquired genetic defect»_space; loss of GPI anchor which connects CD55 and CD59 to cell surface (proteins responsible for inhibiting complement fixation on cell surface). Lack of surface proteins»_space; complement membrane attack complex formation»_space; intravascular and extravascular hemolysis and hemoglobinuria.
Intravascular hemolysis = anemia, low haptoglobin, ^ bili and ^ LDH
What part of the digestive system is responsible for iron absorption?
Duodenum
What is an easy/noninvasive test for multiple myeloma?
Serum electrophoresis - allows you to detect elevated serum monoclonal protein (M spike).
Multiple myeloma is due to proliferation of a single plasma cell line that produces monoclonal immunoglobulin.
CRAB = Calcinosis, Renal Failure, Anemia, and Bone Lesions are common manifestations
Why do you get bone lesions in multiple myeloma?
As disease progresses the bone marrow elements are replaced by malignant plasma cells. Can lead to anemia, leukopenia, and thrombocytopenia.
Why would a bone scan not be useful in finding lesions caused by multiple myeloma?
Bone scans only pick up osteoblastic activity. MM is all osteoclastic.
Since you get megaloblastic anemia and hypersegmented neutrophils with either folate or B12 deficiency, how can you tell which one is actually deficient (any other test)?
- Both folate and B12 are needed in converting homocysteine to methionine, so deficiency in either will cause ^ homocysteine levels. You can isolate the deficiency by measuring serum methylmalonyl CoA levels because B12 (and not folate) is needed to convert methylmalonyl CoA to succinyl CoA.
