[Anemia with hypersideroblastosis during anti-tuberculosis therapy. Cure with vitamin therapy]

The unusual occurrence of microcytic anemia with hypochromia, high iron blood levels and excess of sideroblasts in the bone marrow, observed during the treatment of tuberculosis with isoniazid and rifampicine is reported. Three particularities were noted. First, in our experience, the occurrence of this type of anemia has never been noted previously as a result of these two drugs. Secondly, the improvement of the blood abnormalities was obtained by the combined use of vitamin B6 and vitamin C. Thirdly, the anemia was associated with neuropathy, characterized by areflexia and dysesthesia, which improved with vitamin B6 therapy (but not with vitamin C). Some mechanisms are discussed as being possibly the origin of this kind of anemia, particularly a lack of vitamin B6 resulting from a massive urinary loss of pyridoxal induced by isoniazid as well as both a tissue depletion and an overconsumption of this vitamin. The anemia may be the consequence of a deficiency of hemoglobin synthesis involving probably the first step of the biosynthesis of heme.