Download Macrocytic Anemia

Macrocytic Anemia
CLINICAL PATHOLOGY DEPARTMENT
SCU
Normal blood cells
Complete Blood Count (CBC)
Normal red blood cells
Definition
An (without) -emia (blood):
a reduction below normal
in hemoglobin or red blood cell number
Symptoms and signs of Anemia
 None if mild
 Fatigue
 Breathlessness
 Dizzines
 Pale Skin & mucous membranes
 Jaundice ( if hemolytic)
 Tachycardia
Differential Diagnosis Using MCV
 Macrocytic anemias (MCV = 150 fl): > normal cells
 Normocytic (MCV = 80-96 fl): cells are normal in
volume
 Microcytic anemias (MCV = 50 fl): cells are < normal
Macrocytic anemia
 Defined as MCV > 100 femtoliters
 Identified by peripheral blood smear or automated
RBC indices
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Smear is more sensitive in detecting early macrocytic changes
and small numbers of macrocytes
Cell morphology can aid in determining etiology of
macrocytosis
Common Causes of Macrocytosis
cause
% of cases
Alcohol abuse
36%
B12 or Folate deficiency
21%
Chemotherapy or drugs
11%
Hemolysis or bleeding
7%
Liver disease
6%
Primary bone marrow disorders
5%
Hypothyroidism
5%
Others
12%
Megaloblastic Anemia
 Defective DNA synthesis leads to
nuclear/cytoplasmic asynchrony
 B12/folate deficiency
 Macrocytic anemia with hypersegmented neutrophils
Megaloblastic Anemia
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
retarded DNA synthesis
unimpaired RNA synthesis

BIG cells!
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
immature nucleus
mature cytoplasm
How is B12 involved?
 B12 (and folate) are required for DNA synthesis.
• Slowed DNA synthesis means big, immature nucleus
• Cytoplasm (with RNA in it) matures just fine
 B12 is also required for conversion of homocysteine to
methionine
• ↑ homocysteine = atherosclerosis!
• ↓ methionine = subacute combined degeneration
Megaloblastic anemia
Megaloblastic anemia
Reticulocyte Count
(In the Diagnosis of Anemia)
 Useful in determining response and potential of bone

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marrow.
Reticulocytes are non-nucleated RBCs that still contain
RNA.
Visualized by staining with supravital dyes, including new
methylene blue or brilliant cresyl blue; RNA is precipitated
as dye-protein complex.
Normal range is 0.5-2.0% of all erythrocytes.
If bone marrow responding to anemia, should see increases
in retic count.
Newborns have higher retic count than adults until second
or third week of life.
Retics Slide
Thank You