Microcytic, Hypochromic Anemias Hematology Review 311
ANEMIA ETIOLOGY BLOOD SMEAR OTHER
Iron deficiency
anemia (IDA)
Sideroblastic anemia
b–thalassemia major
b–thalassemia minor
Anemia of chronic
inflammation*
Insufficient iron for hgb
synthesis.
Enzymatic defect in heme
synthesis.
↓b-chain production.
↓b-chain production.
Acute phase reactants (e.g.,
hepcidin) affect iron absorp-
tion & release. Iron in bone
marrow macrophages is not
released to developing RBCs.
Aniso, poik, hypochromic
microcytes
Dual population of RBCs
(normocytic & microcytic),
Pappenheimer bodies,
basophilic stippling
Marked aniso & poik,
hypochromic microcytes,
target cells, ovalocytes,
nRBCs, basophilic stippling
Aniso, poik, hypochromic
microcytes, target cells,
basophilic stippling
60%–70% of cases have
normocytic normochromic
RBCs; 30%–40% microcytic
hypochromic
Most common anemia.
RBC indices usually normal.
Ringed sideroblasts in marrow.
Homozygous. Little or no Hgb A,
95%–98% F, 2%–5% A 2.
Severe anemia. MCV <67 fL.
Heterozygous. >90%–95% Hgb A,
3.5%–7% A 2 , 2%–5% F.
Mild anemia.
Associated with chronic infections &
inflammation, malignancies, autoim-
mune diseases. 2nd most common
anemia after IDA. Most common
anemia in hospitalized pts.
*Formerly known as anemia of chronic disease. More often normocytic normochromic but included here because must be considered in differential Dx of microcytic anemia.