Anemia Flashcards
blood smear
placing a drop of blood on a slide and using another slide to spread it into a thin, even layer that can be stained
centrifuged peripheral blood
RBCs on bottom, plasma up top
what area of the blood smear do you focus on?
the feathered edge
what is the color of a blood smear indicative of?
hematocrit
ideal characteristics of a blood smear
RBCs not touching, central pallor present in most RBCs, not too widely spread apart or distorted
hematocrit
ratio of the volume of RBCs to that of whole blood. typically around 3x [Hb]
MCV (mean red cel volume)
the average volume of a red cell in your specimen
(RDW) red cell distribution width
measure of the variation of the RBC volume in you specimen. standard deviation of the volume over the mean
what do we use as a visual reference range for MCV
the size of a lymphocyte nucleus
microcytosis definition
low MCV <80.
hypochromasia
increased central pallor >1/3 diameter of RBC. usually associated with a low hemoglobin and microcytosis.
macrocytosis definition
high MCV >100.
what does an increased reticulocyte (purplish blue) indicate?
bone marrow is responding to a stimulus to create more red blood cells. measure of marrow’s ability to respond to anemia/hypoxia
anemia definition
a decrease in the number of red blood cells or less than the normal quantity of hemoglobin in the blood. insufficient RBC mass to deliver adequate O2 to tissues
two causes of anemia
decreased erythropoesis, or increased bleeding/RBC destruction
after seeing reduced hematocrit levels, what do you look for?
MCV to determine (micro/normo/macrocytic anemia)
how can you distinguish between destructive/productive problem of anemia?
reticulocyte count: high (destructive/blood loss issue), low (production issue)
MCV count for microcytic anemia
<80
MCV count for normocytic anemia
80-99
MCV count for macrocytic anemia
> 100
4 causes of microcytic anemia
iron deficiency anemia, anemia of chronic inflammation/chronic disease, thalssemia, sideroblastic anemia
iron deficiency anemia
form of microcytic, hypochromic anemia. most common nutritional deficiency in the world, toddler, adolescent women, older adults at risk
patient presentation with iron deficiency anemia
low hemoglobin, low MCV, high RDW. Elliptocytes also present.
thalassemia
problem with hemoglobin synthesis due to abnormalities in synthesis of globin chains (alpha, beta). causes microcytic hypo chromic anemia.
patient presentation with thalassemia
VERY low MCV. presence of target cells
hemolytic anemia
one of the classes of normocytic anemia
hereditary spherocytosis
defect in RBC cytoskeleton. normochromic, normocytic hemolytic anemia. high reticulocyte count (polychromasia). undergo increased hemolysis in spleen, shorter lifespan
spherocyte
RBCs that have lost membrane and take on a spherical shape. lack central pallor.
common causes of macrocytic anemia
megaloblastic anemia, liver disease, alcohol
megaloblastic anemia
vitamin B12 or folate deficiency that leads to ineffective erthryopoesis due to defects in DNA synthesis.
patient presentation with megaloblastic anemia
large RBCs and hyper segmented neutrophils
life span of RBCs
120 days
role of G6PD in RBC
protection from oxidative damage (maintains NADPH for glutathione)
where are senescent RBCs destroyed?
spleen
advantage of sigmoid O2-Hb dissociation curve?
releases O2 at low partial pressure (deoxygenated tissues) and binds O2 at high partial pressure (lungs)
what right shifts O2-Hb curve?
decreased pH, increased CO2, increased temperature, increased 2,3-DPG (all leading to reduced oxygen affinity/increased oxygen unloading)
what left shifts O2-Hb curve?
increased pH, decreased CO2, decreased temperature, decreased 2,3-DPG, CO poisoning (all leading to increased affinity/decreased unloading)
cytokine most important for erythroblast formation from stem cell?
EPO
where is EPO made?
kidney
what induces kidney to secrete EPO?
hypoxia, anemia (reduced levels of oxygen in tissues)
via HIF-1
how does EPO induce erythroblast formation?
stimulates erythroid cells in bone marrow to proliferate
what CBC values are low in anemia?
RBC count, Hemoglobin levels, Hematocrit
5 possible causes of anemia
kidney disease (decreased EPO), EPO unable to stimulate marrow, bone marrow disorder, blood loss, decreased red cell survival
how to mechanistically classify of anemia
reticulocyte levels
how to morphologically classify of anemia
MCV
low reticulocyte count
marrow isn’t active or marrow disorder or decreased EPO (<1ish%)
high reticulocyte count
marrow is healthy and compensating as in hemolysis or bleeding (>1ish%)
corrected reticulate count
takes into account actual number being made rather than percentage. corrects for anemia
formula for corrected reticulocyte count
%reticulocytes* (actual hematocrit/45)
causes of decreased RBC production
iron/B12/folate deficiencies (no building blocks), anemia from chronic disease (can’t use iron), renal disease (EPO deficiency), aplastic anemia/toxins/immune mediated (lack of RBC precursors)
causes of intracorpuscular RBC destruction
abnormal membrane, enzyme deficiency, abnormal Hb, thalassemia
causes of extra corpuscular RBC destruction
immune hemolytic anemia, RBC fragmentation, infection (malaria)
reticulocyte count after acute bleeding
will take 2-7 days to increase
reticulocyte count after occult bleeding
initially elevated but over time, with loss of iron, levels decrease from normal
mild anemia Hb levels
10-12
moderate anemia Hb levels
8-10
severe anemia Hb levels
<8
signs and symptoms of anemia related to low oxygen delivery
fatigue, decreased exercise tolerance, light headedness, skin/conjunctiva/nail bed pallor
signs and symptoms of anemia related to cardiovascular response
rapid, bounding pulse >100. dyspnea, heart failure
signs and symptoms of anemia due to iron deficiency
spoon like nail changes, pica
symptom of anemia due to hemolysis
jaundice
hypovolemia
low blood volume, usually due to trauma and rapid loss of blood –> acute anemia
signs and symptoms of hypovolemia
SHOCK: pale/damp skin, low blood pressure on standing, weak pulse, confusion/coma, decreased urine output
