Oral treatment in selective vitamin B12 malabsorption.

PURPOSE

The efficacy of oral treatment with megadose vitamin B12 in a patient with selective vitamin B12 malabsorption is studied.

PATIENTS AND METHODS

An 8-year-old boy with megaloblastic anemia due to selective vitamin B12 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 B12 level 87 pmol/L. There was proteinuria. Replacement treatment with oral B12 1,000 micrograms/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 B12 is given at a dose larger than that of parenteral therapy.