1. Clinical pathology department SCU
Macrocytic Anemia
Clinical pathology department
SCU

2. Normal blood cells

3. Complete Blood Count (CBC)
Normal red blood cells

4. Definition
An (without) -emia (blood): a reduction below normal in hemoglobin or red blood cell number

5. Symptoms and signs of Anemia
None if mild
Fatigue
Breathlessness
Dizzines
Pale Skin & mucous membranes
Jaundice ( if hemolytic)
Tachycardia

6. Differential Diagnosis Using MCV
Macrocytic anemias (MCV = 150 fl): > normal cells
Normocytic (MCV = fl): cells are normal in volume
Microcytic anemias (MCV = 50 fl): cells are < normal

7. Macrocytic anemia Defined as MCV > 100 femtoliters
Identified by peripheral blood smear or automated RBC indices
Smear is more sensitive in detecting early macrocytic changes and small numbers of macrocytes
Cell morphology can aid in determining etiology of macrocytosis

8. Common Causes of Macrocytosis
% 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
Others
12%

9. Megaloblastic Anemia
Defective DNA synthesis leads to nuclear/cytoplasmic asynchrony
B12/folate deficiency
Macrocytic anemia with hypersegmented neutrophils

10. BIG cells! Megaloblastic Anemia retarded DNA synthesis
unimpaired RNA synthesis
BIG cells!
immature nucleus
mature cytoplasm

11. 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

12. Megaloblastic anemia

13. Megaloblastic anemia

14. Reticulocyte Count (In the Diagnosis of Anemia)
Useful in determining response and potential of bone 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 % 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.

15. Retics Slide

17. Thank You