[Hypophosphatemia following the administration of intravenous iron formulations: A case report and literature review]. / Hypophosphatémie et fer injectable : à propos d'un cas et revue de la littérature.

Iron deficiency and iron-deficiency anemia are common medical conditions. Management of the etiology and iron supplementation are both necessary to treat this condition. Use of intravenous iron preparations is increasing due to its advantages over oral iron. Indeed, the total dose required can be provided in a single infusion, and it is more effective and increases hemoglobin levels more quickly than oral iron. Hypophosphatemia, sometimes severe, following intravenous iron administration, has been described in literature these past years, in particular with ferric carboxymaltose. We report here a case of severe hypophosphatemia with ferric carboxymaltose and carry out a literature review to determine the incidence of hypophosphatemia and to precise its clinical presentation, its pathophysiological mechanisms and its treatment. We found that hypophosphatemia is frequent with ferric carboxymaltose. Most of the time, there are no clinical manifestations, but cases of symptomatic osteomalacia have been described. Duration of hypophosphatemia is variable, from a few weeks to several months in case of prolonged administration. Hypophosphatemia owing to renal phosphate wasting is caused by an increase in intact fibroblast growth factor 23 (FGF-23) levels. However, the mechanism of ferric carboxymaltose- induced increase in intact FGF-23 is still unknown.