120814 intro to anemia

Question 1

anemia

Answer 1

decreased circulating RBC mass (can’t directly measure, so use surrogates)

Question 2

compensatory mechanisms in anemia

Answer 2

increased RBC production
increased 2,3-DPG
shunting of blood from non-vital to vital areas
increased cardiac output
increased pulmonary fxn

Question 3

signs and symptoms of anemia

Answer 3

weakness, fatigue (tissue hypoxia)

marrow expansion with potential bony abnormalities (increased RBC production)–in severe, chronic anemia

pallor (shunting of blood)

tachycardia (increased cardiac output)

dyspnea on exertion (increased pulmonary fxn)

Question 4

functional classification of anemia

Answer 4

blood loss
decreased production
accelerated destruction

Question 5

investigation of anemia-what to look at

Answer 5

clinical history and PE get you 90% of the way
CBC
reticulocyte count
examination of peripheral blood smear
specific diagnostic tests

Question 6

most important parameter in CBC for assessing O2 carrying capacity of blood

Answer 6

hemoglobin

Question 7

hematocrit provides what kind of information?

Answer 7

RBC volume out of total blood volume, but it’s redundant if you have hemoglobin

Question 8

RBC count

Answer 8

number of RBCs per unit volume

generally correlates well with Hb and hematocrit in CBC so adds little independent info

Question 9

MCV

Answer 9

mean cellular volume

very useful in differential diagnosis of anemia (microcytic, normocytic, macrocytic)

Question 10

microcytic anemia differential diagnosis

Answer 10

iron deficiency
thalassemia
anemia of chronic disease
other (rare)

Question 11

macrocytic anemia differential diagnosis

Answer 11

megaloblastic (impaired DNA synthesis):
B12 and folate deficiency
some drugs
myelodysplastic syndromes

non-megaloblastic (other mechanisms):
reticulocytosis
liver disease
hypothyroidism
some drugs

Question 12

MCH

Answer 12

mean corpuscular hemoglobin
calculated as Hb/RBC
high correlation with MCV
obsolete in utility

Question 13

MCHC

Answer 13

mean corpuscular hemoglobin concentration
measure of how chromic RBCs are
calculated as Hb/(MCVxRBC)
it’s decreased in hypochromic anemias and vice versa

Question 14

RDS

Answer 14

red cell distribution width
measure of variability of red cell volume
useful for separation of anisocytotic anemias (Fe deficiency) from non-anisocytotic anemias (anemia of chronic disease)

Question 15

bite cells represent

Answer 15

increased oxidant stress

Question 16

Howell Jolly bodies are

Answer 16

nuclear fragments

Question 17

rouleaux

Answer 17

single file stack of coins-RBCs

Question 18

agglutination

Answer 18

3-D clumps of RBCs due to Ig cross-linking RBCs

Question 19

in acute blood loss anemia, when does reticulocyte count peak?

Answer 19

after 7-10 days

Question 20

what happens in chronic blood loss anemia?

Answer 20

no anemia initially because bone marrow compensates

eventual development of IRON DEFICIENCY with resultant iron deficiency anemia

Question 21

reticulocyte%’s problem

Answer 21

reticulocyte percent varies depending on total RBC count

so need to correct for it

or another solution-get absolute reticulocyte count

Question 22

decreased RBC production types

Answer 22

ineffective erytropoiesis

decreased RBC precursors (marrow failure)–stem cell defects with adequate erythropoietin, marrow replacement, decreased erythropoietin

anemia of chronic disease

Question 23

intravascular free Hb goes on to

Answer 23

be combined with haptoglobin. goes to liver and is cleared

sometimes you get free heme. free heme combines with hemopexin and goes to the liver as well

Question 24

hemolysis-general features

Answer 24

reticulocytosis
increased indirect bilirubin from heme catabolism
increased LDH released from destroyed RBCs
decreased haptoglobin (no feedback mechanism)
morphologic abnormalities of red cells in specific disorders

spenomegaly in chronic cases (spleen works hard to clear RBCs)
bony abnormalities in severe chronic hemolytic anemias