Red Blood Cell Disorders Flashcards
What is hematopoiesis - and what sites produce RBC
Creation of RBCs and as a fetus occurs in the the spleen, LNs and liver, moves into bone marrow and is produced there from birth and in adulthood.
Approach to anemia
Macrocyctic (High MCV) - B12/folate deficiency, drug induced, liver disease, hypothyroidism
Microcytic (Low MCV) - Thalassemia, chronic disease, iron deficiency, lead pointing, sideroblastic
Normocytic (normal MCV) - bleeding/ hemolysis (high reticulocytes), aplastic, renal disease, leukaemia (low reticulocytes)
How do the kidneys regulate RBCs?
EPO - kidney senses low O2 and releases EPO from HIF2Alpha, if kidney damage will have anemia
Mechanism of coagulation
Vasoconstriction, Primary hemostasis - platelet aggregation (VWF), secondary hemostasis (formation for platelet clot - fibrin clot formation - cross linking), fibrinolysis
Order of the clotting cascade?
12. 11. 9. 7 8. 3 10 5 2 1
7 is the extrinsic pathway, 12 is the intrinsic, Fibrin is activated factor 13 which is activated by the common pathway, and factor 10 activates thrombin
Mechanism of clot break down
TPA converts plain which cuts up the fibrin mesh, and healthy cells actually secrete things to prevent breakdown
D- dimer is the breakdown products
Vitamin K dependant clotting factors?
2, 7, 9, 10 - needed to convert to functional form, produced by gut bacteria and found in diet. Warfarin stops recycling vitamin K
When to transfuse blood
Hbg <70 and symptomatic, consider if hemodynamically stable
Iron supplementation?
Ferrous gluconate is the preferred supplementation - ideally three times a day. But it not tolerated very well.
IV - people will get a reaction, just order Benadryl in advance.
What does ferritin indicate? What is the TIBC?
Serum ferritin - indicated level of iron stores - low = iron deficiency, high can be an inflammatory marker
TIBC - indirect measure of transferrin (transporter that allows for cellular storage)
Reason for anemia in CKD?
Decreased EPO.
Signs and Sx of anemia
Pallor, fatigue, tachycardia, nail changes, glossitis
How do you test for hemolytic disease of the newborn?
direct coombs
What is HUS? And what is it caused by?
Hemolysis due to shiga toxin (e.coli) - most common cause
Will present with AKI, bloody diarrhea, weakness, fatigue
What causes TTP?
Deficiency of ADAMTS13, clotting in small vessels leading to low platelet count. Results from excessive vWF on platelets