Masked Megaloblastic Anemia

The impact of vegetarianism on some haematological parameters

“…Our data supplied evidence that vitamin B12 deficiency‐induced macrocytosis can be masked when iron status is in a state of negative balance (Fig. 3) (11, 12). Vitamin B12 deficiency might induce a secondary defect in the enterocytes, which may further cause iron loss before being assimilated (8).…”

“…A vegetarian diet is therefore common ground for the etiologies of vitamin B12 and iron deficiencies. Concomitant vitamin B12 and iron deficiencies may be presented in the absence of a classic haematological picture (11–13). Additionally, vitamin B12 and iron deficiencies were related to increased susceptibility to infectious diseases, which has suggested a role for these micronutrients in the immune system (14, 15).…”

M.C.V. should not be the only criteria to order vitamin B12 for anemia under evaluation

“…These findings suggest that concomitant iron or other nutritional deficiencies or hemoglobinopathies [21,28,29] may have been responsible for the normal or even low MCV values in some of our anemic patients; such anemias and hemoglobinopathies have been seen commonly in Southeast Asians [21,[30][31][32]. Moreover, the combination in anemia has been reported in the literature [33][34][35]. Thompson et al reported that 82% of patients with low B12 levels seen at Bellevue Hospital, New York, had MCV values below 95 fL; they suggested that further evaluation of the suspected B12 deficiency should not be deterred by a normal MCV value which is one of the important observation in our study [36].…”

Reversible severe combined immunodeficiency phenotype secondary to a mutation of the proton-coupled folate transporter

“…Combined deficiencies of either folate or B12 deficiency with a concurrent iron deficiency are known to mask the macrocytosis generally seen with megaloblastic anemia. In fact, replacement of one deficiency can result in emergence of the typical phenotype of the untreated deficiency [21]. Our patient had both iron and folate deficiencies at presentation.…”