hematologic - anemias Flashcards
erythrocyte definition
red blood cell
reticulocyte definition
immature erythrocyte (day 1 or 2 in the bloodstream)
anemia definition
deficient number of RBCs
mean corpuscle volume
size of RBC
normocytic
normal sized cells
microcytic
smaller than normal size cells
macrocytic
larger than normal size cells
hemoglobin
four folded globin chains (2 alpha and 2 beta)
hemolytic anemia
abnormal hemolysis (breakdown) of RBCs
RBC primary function
transport hemoglobin which transports oxygen to the tissue
CO2 + H2O —>(carbonic anhydrase)
H2C03 –> HCO3 + H
what enzyme do RBCs contain and what does it do
carbonic anhydrase - catalyzes the reaction between CO2 and H2O to form carbonic acid (H2Co3)
and transports CO2 in the form of HCO3 to the lungs for removal
where are RBCs produced
in the bone marrow
any condition that decreases oxygen transport to tissues will stimulate
erythropoietin (glycoprotein formed in the kidneys)
erythropoiesis definition
RBC production and maturation
erythropoiesis process
pluripotent hematopoietic stem cell –> proerythroblast –> erythroblast –> reticulocyte –> erythrocyte
what percent of circulating RBCs are reticulocytes?
about 1%
anemia definition
reduced number of circulating RBCs = decreased oxygen carrying capacity
according to the WHO anemia is defined as Hgb concentration as ___ for women and ___ for men
12 g/dL for women
<13 g/dL for men
what does a physiologic anemia mean?
decreased Hct in relation to increase in plasma volume in pregnant women
polycythemia definition
increase in circulating RBCs
increased blood viscosity
some causes of anemia (broad/general terms)
blood loss
decreased production of RBCs
increased destruction of RBCs
symptoms of anemia
fatigue, tachycardia, SOB, dizziness, paleness, coldness, muscle weakness, splenomegaly, angina/chest pain, hypotension, yellowing of skin or eyes
in acute blood loss the body replaces the fluid portion of plasma in
1-3 days leaving a low concentration of RBCs
in acute blood loss when does the RBC concentration return to normal usually?
within 3-6 weeks
in chronic blood loss patients
cannot absorb enough iron from the gut to make Hgb as rapidly as it is lost so RBCs are much smaller and have little Hgb inside them (microcytic hypochromic anemia)
“10/30 rule”
transfuse if the Hgb level is <10g/dL or the Hct is <30%
clear evidence to Hgb levels below ____ benefit from transfusion
6 g/dL
active coronary artery disease may require
lower transfusion thresholds
RBC transfusions can transmit
hep B, C, HIV
EBL <15%
rarely requires transfusions
EBL 30%
replacement with crystalloids/albumins
EBL 30-40%
RBC transfusion
EBL >50%
massive transfusion (will need FFP and plts too)
types of anemia from decreased RBC production
iron deficiency, autoimmune
types of anemia from increased destruction of RBCs
thalassemia, hemolytic anemia, sickle cell