2. Definition of Anemia
Deficiency in the oxygen-carrying capacity
of the blood due to a diminished
erythrocyte mass.
May be due to:
Erythrocyte loss (bleeding)
Decreased Erythrocyte production
low erythropoietin
Decreased marrow response to erythropoietin
Increased Erythrocyte destruction
(hemolysis)
3. Measurements of Anemia
Hemoglobin = grams of hemoglobin per 100 mL of
whole blood (g/dL)
Hematocrit = percent of a sample of whole blood
occupied by intact red blood cells
RBC = millions of red blood cells per microL of whole
blood
MCV = Mean corpuscular volume
If > 96 → Macrocytic anemia
If 76 – 96→ Normocytic anemia
If < 76 → Microcytic anemia
RDW = Red blood cell distribution width
= (Standard deviation of red cell volume ÷ mean cell
volume) × 100
Normal value is 11-15%
If elevated, suggests large variability in sizes of RBCs
6. RBC Life Cycle
In the bone marrow, erythropoietin
enhances the growth of differentiation of
burst forming units-erythroid (BFU-E) and
colony forming units-erythroid (CFU-E) into
reticulocytes.
Reticulocyte spends three days maturing in
the marrow, and then one day maturing in
the peripheral blood.
A mature Red Blood Cell circulates in the
peripheral blood for 100 to 120 days.
Under steady state conditions, the rate of
RBC production equals the rate of RBC loss.
7. Classification of Anemia
Anemia can be either acute or chronic.
In acute anemia (sudden loss of blood), the lack of blood
volume in the circulatory system is more important than
the deficiency of hemoglobin. A loss up to 10% of blood
volume, as that taking place upon blood donation, is well
tolerated. Losses between 10 and 20% cause postural
hypotension, dizziness and faint. In losses above 20%,
there's tachycardia, cold extremities, extreme paleness
and hypotension, followed by shock; should the loss
surmount 30%, without immediate replacement of
intravenous fluids, the shock rapidly becomes
irreversible and fatal.
In chronic anemia, there's no decrease in blood volume,
which is compensated by an increase in plasma volume
8. Classification of Anemia on
the Basis of MCV
Microcytic anemia(MCV<76)
Normocytic anemia(MCV=76-96)
Macrocytic anemia(MCV>96)
10. Classification of Anemia
One way to classify anemia is by RBC size (i.e., MCV), as
microcytic, macrocytic, or normocytic. For the microcytic
anemias, the etiologic possibilities are iron deficiency,
thalassemia, sideroblastic anemia, and the anemias of chronic
disease. Severe microcytic anemia (MCV <70 fL) is caused
mainly by iron deficiency or thalassemia. Macrocytic anemia
may be the result of megaloblastic (folate or vitamin B12
deficiency) or nonmegaloblastic causes. Folate deficiency can in
turn be due to either reduced intake or diminished absorption.
Severe macrocytic anemia (MCV >96fL) is almost always
megaloblastic. In some rare cases, macrocytic anemia is
related to the myelodysplastic syndromes prior to or after
chemotherapy.
The causes of normocytic anemias include aplastic anemia,
bone-marrow replacement, pure red-cell aplasia, anemias of
chronic disease, hemolytic anemia, and recent blood loss. A
number of anemias have a genetic etiology. Examples of such
inherited disorders include hereditary spherocytosis and
sickle-cell (SC) anemia
11.
12. Hypochromic Microcytic Anemia
Microcytic anemias
the etiologic possibilities are
Iron deficiency
Thalassemia
Sideroblastic anemia
Anemias of chronic disease.
Severe microcytic anemia (MCV <76 fL) is
caused mainly by iron deficiency or thalassemia.
15. Iron Deficiency Anemia – Lab
Findings
Serum Iron
LOW (< 60 micrograms/dL)
Total Iron Binding Capacity (TIBC)
HIGH ( > 360 micrograms/dL)
Serum Ferritin
LOW (< 20 nanograms/mL)
Can be “falsely”normal in inflammatory
states
16. TEST Iron def ThalMin An of ch dis
S.Iron - low normal normal
S.Ferritin - low N/H N/H
Marrow iron - low N/H N/H
Hb A2 or F - N H=Bthal N
N=Athal
RDW - high normal N/H
17. Thalassemia
Microcytic anemia
Defects in either the alpha or beta chains of
hemoglobin, leading to ineffective
erythropoiesis and hemolysis
α-thalassemia:
Prevalent in Africa, Mediterranean, Middle
East, Asia
β-thalassemia:
Prevalent in Mediterranean, South East
Asia, India, Pakistan
Smear shows microcytosis with target cells
20. The causes of normocytic anemias include aplastic
anemia, bone-marrow replacement, pure red-cell
aplasia, anemias of chronic disease, hemolytic anemia,
and recent blood loss. A number of anemias have a
genetic etiology. Examples of such inherited disorders
include hereditary spherocytosis, sickle-cell (SC) anemia,
and thalassemia
24. Macrocytic anemia may be the result of megaloblastic
(folate or vitamin B12 deficiency) or nonmegaloblastic
causes. Folate deficiency can in turn be due to either
reduced intake or diminished absorption. Severe
macrocytic anemia (MCV >125 fL) is almost always
megaloblastic.
26. Vitamin B12 Deficiency Versus
Folate Deficiency
Vitamin B 12
Deficiency
Folate Deficiency
MCV > 100 > 100
Smear Macrocytosis with
hypersegmented
neutrophils
Macrocytosis with
hypersegmented
neutrophils
Pernicious anemia Yes NO
Homocystine Elevated Elevated
Methylmalonic Acid Elevated NORMAL
27. Anemia due to Destruction of
Red Blood Cells
Hemoglobinopathies
Sickle Cell Anemia
Aplastic Anemia
Decrease in all lines of cells – hemoglobin,
hematocrit, WBC, platelets
Parvovirus B19, EBV, CMV
Acquired aplastic anemia
Hemolytic Anemia
28. Hemolytic Anemias
Hereditary spherocytosis
Glucose-6-phosphate
dehydrogenase (G6PD)
Deficiency
Most common enzyme defect in
erythrocytes
X-linked
Brisk hemolysis when patients
exposed to oxidative stress from
drugs, infections or toxins.
Thrombotic Thrombocytopenic
Purpura (TTP)
Thrombocytopenia and
microangiopathic hemolytic
anemia, fever, renal
insufficiency, neurologic
symptoms
Schistocytes on smear
Hemolytic Uremic Syndrome
Thrombocytopenia,
Microangiopathic hemolytic
anemia, renal insufficiency
Autoimmune Hemolytic Anemia
Warm-antibody mediated
IgG antibody binds to erythrocyte
surface
most common
Diagnosed by POSITIVE Coomb’s
Test (detectgs IgG or complement
on the cell surgace)
Can be caused drugs
Treated with corticosteroids or
splenectomy if refractory
Cold agglutinin Disease
IgM antibodies bind to erythrocyte
surface
Does not respond to corticosteroids,
but usually mild.
Infections
Malaria
Babesiosis
Sepsis
Trauma
Includes some snake, insect bites