Recurrent severe hypophosphatemia following intravenous iron administration

Key Clinical Message Hypophosphatemia postintravenous iron is frequent but under‐recognized. If prolonged or recurrent, it can cause osteomalacia. The likely mechanisms are direct toxicity to proximal tubular cells causing phosphate wasting, elevated Fibroblast growth factor‐23 (FGF‐23), and reduced 1,25‐dihydroxyvitamin D (1,25(OH) 2 D). Hypophosphatemia may be severe and persist for months, necessitating phosphate replacement until normalization of serum levels occurs.