1. Megaloblastic anemia Folic acid deficiency
Due to B12 and folate deficiencies.
Folic acid deficiency
Sources and requirements:
Known as folate or petroyl glutamic acid.
Water soluble.
Present in a variety of foods (green leafy vegetables, fruits and liver and kidney).
Heat labile vitamin.
Dietary intake for adults 30µg/kg per day.

2. Structure: Folic acid Made of three components.
Pterdine Amino benzoic acid Gultamic acid
(Poly Glutamic Acid)
Folic acid
Made of three components.
Folic acid derived from diet is not biologically active.
Once absorbed through the duodenum it hydrolyzed, reduced and methylated to form MTHF.
Other form THF (biologically active).

3. Methyl Tetrahydrfolate
Absorption and metabolism
Intestine
Diet
Poly glutamate
Poly glutamic acid
Folate reductase
Glu
Mono glutamate
Reduced and methylated
CH3THF
Methyl Tetrahydrfolate

4. DNA Synthesis cTHF Glu THF Methionine Homocysteine CH3THF CH3THF
Tissue cell
Circulation

5. Causes of folic acid deficiency
The main causes is decrease dietary intake:
Old age,
Alcoholism
Chronic diseases.
Mal absorption:
Tropical sprue.
Gluten-sensitive enteropathy.
Increase requirements:
Pregnancy.
Infancy.
Malignancy.
Drugs:
Methotrexate, oral contraceptives.

6. Laboratory diagnosis of megaloblastic anemia
CBC
Low hemoglobin level and elevated MCV.
PB morphology
Macrocytosis, macroovalocytes and hyper segmented neutrophils.
Chemical testing
Serum folic acid Low (RC FA) BM
Hyper cellular BM.
Megaloblastic picture (large cells with increased RNA per DNA unit.

7. Nuclear chromatin appears loose and less mature than nuclear chromatin of normal red cells.
Megakaryocytes may be hypersegmented.
Giant bands and hypersegmented polymorphonuclear neutrophils are common.

8. Differential Lab Diagnosis of Megaloblastic anemia
High MCV
>98 fl
Check smear for macrocytes and hyper segmented neutrophils
Yes NO
Serum B12
Serum folate
Red cell folate
All normal
Alcoholism
Liver diease
?Hematologic diease
Decreased level of B12
Decreased red cell folate
Anti-IF antibodies
Folic acid deficiency

9. Anti-IF antibodies No
Yes
Schilling test
Abnormal
corrected
with IF
Abnormal
Not corrected IF
Normal
Dietary deficiency
P.A.
Mal absorption