Maturation failure in poor absorption of the vitamin B12 causes:

(Occurs in 3-4 months after absorption): Ref: 682-R (438- Basic pathology 8th)Vitamin B12 deficiency* Macrocytic megalablastic anaemia is the cardinal features* Usually pernicious (Addisonian) anaemiaDiagnostic features include:1. A moderate to severe megaloblastic anaemia2. Leukopenia with hypersegmented granulocytes3. Mild to moderate thrombocytopenia4. Mild jaundice due to ineffective erythropoisis and peripheral hemolysis of red cells5. Neurologic changes related to involvement of the posterolateral spinal tracts6. Achlorhydria even after histamine stimulation7. Inability to absorb an oral dose of cobalamin (assessed by urinary excretion of radio labeled cyanocobalamin given orally, called the shilling test)8. Low serum levels of vitamin Bj2 (less than 100 pg/ml)9. Elevated levels of homocysteine and methylmalonic acid in the serum (This is more sensitive than serum levels of vitamin B!2)10. A striking reticulocytic response and improvements in hematocrit levels beginning about 5 days after IV administration of vitamin B12. Serum antibodies to intrinsic factor are highly specific for pernicious anemia. Their presence attests to the cause of vitamin B12 deficiency, rather than the presence or absence of cobalamine deficiency.Polvcvthaemia - Vitamin B12 levels are strikingly elevated because of increased levels of transcobalamin III (501- CMDT-06)* Deficiency of vitamin B12 takes at least 2 years to develop when the body stores are totally depleted. (380-HM)