Megaloblastic anemia Due to B 12 and folate

Megaloblastic anemia Due to B 12 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.

Structure: 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). Pterdine Amino benzoic acid Gultamic acid (Poly Glutamic Acid)

Absorption and metabolism Intestine Diet Poly glutamate Poly glutamic acid Folate reductase Mono glutamate ed uc d Re ed lat y eth dm an CH 3 THF Methyl Tetrahydrfolate Glu

DNA Synthesis c. THF Glu THF Homocysteine Methionine CH 3 THF Tissue cell Circulation

Causes of folic acid deficiency 1. The main causes is decrease dietary intake: • Old age, • Alcoholism • Chronic diseases. 2. Mal absorption: • Tropical sprue. • Gluten-sensitive enteropathy. 3. Increase requirements: • Pregnancy. • Infancy. • Malignancy. 4. Drugs: • Methotrexate, oral contraceptives.

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.

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.

Differential Lab Diagnosis of Megaloblastic anemia High MCV >98 fl Check smear for macrocytes and hyper segmented neutrophils Yes Serum B 12 Serum folate Red cell folate NO All normal Alcoholism Liver diease ? Hematologic diease Decreased level of B 12 Decreased red cell folate Anti-IF antibodies Folic acid deficiency

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