Intravenous iron overdose: treat the patient not the number

Decreased Clinical Toxicity and Two-Phase Elimination Kinetics Observed After Intravenous Iron Sucrose Overdose

BACKGROUND

Management of oral iron overdoses is well-established, but there is limited literature regarding intravenous iron sucrose overdoses. Indications for administering deferoxamine after oral iron overdoses include clinical signs and symptoms of toxicity, along with a serum iron concentration ≥ 500 μg/dL. Reported signs and symptoms of iron sucrose overdose do not appear to correlate with those of oral iron overdoses.

CASE REPORT

We present a case of intravenous iron sucrose overdose in a clinically well-appearing patient with a presenting serum iron concentration that was several times higher than the usual threshold concentration for initiating deferoxamine treatment. A 21-year-old woman presented to the emergency department after an accidental intravenous iron sucrose overdose. The patient received a home infusion of 1000 mg iron sucrose, which was five times the prescribed dose. Her presenting serum iron concentration was 1799 μg/dL, with bicarbonate and anion gap both within normal limits and an unremarkable physical examination. Because she did not have evidence of severe iron toxicity, she was treated supportively and deferoxamine was not administered. Her serum iron concentration decreased below the toxic range over the next 14 h, and she was discharged home the next day. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This patient was managed successfully with expectant care alone, suggesting that iron sucrose overdose has much lower toxicity than oral iron salt overdose. This discrepancy between measured iron concentrations and clinical presentation may be explained by the elimination kinetics of iron sucrose having separate redistribution and elimination phases.

The Toxic Influence of Excess Free Iron on Red Blood Cells in the Biophysical Experiment: An In Vitro Study

Iron is needed for life-essential processes, but free iron overload causes dangerous clinical consequences. The study of the role of red blood cells (RBCs) in the influence of excess free iron in the blood on the pathological consequences in an organism is relevant. Here, in a direct biophysical experiment in vitro, we studied the action of free iron overload on the packed red blood cell (pRBC) characteristics. In experiments, we incubated pRBCs with the ferrous sulfate solution (Fe²⁺). Wе used free iron in a wide range of concentrations. High Fe²⁺ concentrations made us possible to establish the pattern of the toxic effect of excess iron on pRBCs during a reduced incubation time in a biophysical experiment in vitro. It was found that excess free iron causes changes in pRBC morphology, the appearance of bridges between cells, and the formation of clots, increasing the membrane stiffness and methemoglobin concentration. We created a kinetic model of changes in the hemoglobin derivatives. The complex of simultaneous distortions of pRBCs established in our experiments can be taken into account when studying the mechanism of the toxic influence of excess free iron in the blood on pathological changes in an organism.