Practice Essentials
Iron overdose has been one of the leading causes of poisoning deaths in children younger than 6 years. Iron is used in pediatric and prenatal vitamin and mineral supplements and for treatment of anemia. Iron tablets are particularly tempting to young children because they look like candy. Iron overdose in adults is typically a suicide attempt. [1]
Iron overload may develop chronically as well, especially in patients requiring multiple transfusions of red blood cells. This condition develops in patients with sickle cell disease, thalassemia, and hematologic malignancies such as myelodysplastic syndromes. [2, 3, 4]
For full discussion of iron toxicity in children, see Pediatric Iron Toxicity.
Pathophysiology
Iron toxicity can be classified as corrosive or cellular. Ingested iron can have an extremely corrosive effect on the gastrointestinal (GI) mucosa, which can manifest as nausea, vomiting, abdominal pain, hematemesis, and diarrhea; patients may become hypovolemic because of significant fluid and blood loss.
Cellular toxicity occurs with the absorption of excessive quantities of ingested iron. Severe overdose causes impaired oxidative phosphorylation and mitochondrial dysfunction, which can result in cellular death. The liver is one of the organs most affected by cellular iron toxicity, but other organs such as the heart, kidneys, lungs, and the hematologic systems also may be impaired. With chronic iron overload, the deposit of iron into the heart may cause death due to myocardial siderosis.
With both corrosive and cellular toxicity, the end result is significant metabolic acidosis, due to several factors. Hypoperfusion due to significant volume loss, vasodilatation, and negative inotropic effect of iron will result in lactic acidosis. Inhibition of oxidative phosphorylation will promote anaerobic metabolism.
Individuals demonstrate signs of GI toxicity after ingestion of more than 20 mg/kg. Moderate intoxication occurs when ingestion of elemental iron exceeds 40 mg/kg. Ingestions exceeding 60 mg/kg can cause severe toxicity and may be lethal. [5]
Suggested iron doses are based on calculation of the amount of elemental iron. Different iron preparations (salts) contain different amounts of elemental iron, as follows:
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Fumarate - 33%
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Sulfate - 20%
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Gluconate - 12%
Epidemiology
The 2021 Annual Report of the American Association of Poison Control Centers' (AAPCC) National Poison Data System reported 5311 single exposures to iron or iron salts, with 14 major outcomes and 2 deaths. In addition, the AAPCC reported 6029 single exposures to multiple vitamins containing iron, with one major outcome and no deaths. Overall, 79% of cases were in children younger than 6 years. [6]
Patient Education
Safekeeping of all medications, not just iron pills, from young children is important. Common medicines and vitamins may be lethal. Also see Vitamin Toxicity. The most effective measure to prevent iron ingestion is to store iron tablets in areas that are inaccessable to children.
For patient education information, see the First Aid and Injuries Center, as well as Iron Poisoning in Children and Poison Proofing Your Home.
