Stem cell steal after intravenous iron: a case of transient thrombocytopenia in severe iron deficiency anaemia

Background: Iron-deficiency anaemia (IDA) commonly presents with reactive thrombocytosis. A less recognized, paradoxical decline in platelets may occur shortly after iron repletion. This phenomenon is most notably seen with intravenous (IV) formulations and termed the platelet steal effect. Case report: We describe a 68-year-old man with severe IDA (haemoglobin 6.6 g/dl; mean corpuscular volume 53.4 fl; ferritin 8.7 ng/ml; iron saturation 3.4%) who developed marked thrombocytopenia after initiation of IV iron. The platelet count trended down from 290 ×103/µl on admission to a nadir of 39 ×103/µl by hospital day 5 without bleeding. Other causes of thrombocytopenia were systematically excluded. Iron therapy was continued and transitioned to oral supplementation; platelets stabilized by day 10 and recovered thereafter in parallel with haemoglobin improvement. Conclusion: Transient thrombocytopenia following iron repletion is likely under-recognized. Awareness of its timing and benign course may prevent unnecessary testing or interruption of definitive IDA therapy.