Oral treatment in selective vitamin B-12 malabsorption

Purpose: The efficacy of oral treatment with megadose vitamin B-12 in a patient with selective vitamin Bit malabsorption is studied. Patients and Methods: An 8-year-old boy with megaloblastic anemia due to selective vitamin B-12 malabsorption is presented. His history was significant for anemia of 4 years duration, requiring transfusion on two occasions. On admission, the Hb was 7.9 g/dL, WBC 6 x 10(9)/L, mean corpuscular volume 124 fl, red cell distribution width 16.8%, platelets 156 x 10(9)/L, reticulocyte 0.04%, and the serum vitamin B-12 level 87 pmol/L. There was proteinuria. Replacement treatment with oral B-12 1,000 mu g/daily was instituted. Results: Reticulocytosis was observed on the third day of treatment, which was followed by a gradual increase in Hb level to 12 g/dL in 3 weeks. A Schilling test performed after a 5-day interruption of therapy was compatible with malabsorption. Conclusions: Our study suggests that the oral route is as effective as the parenteral route when vitamin B-12 is given at a dose larger than that of parenteral therapy.