From the Guidelines
Yes, iron overdose can cause anion gap metabolic acidosis. In acute iron poisoning, the ferrous (Fe2+) iron directly damages mitochondria and disrupts cellular metabolism, leading to lactic acid production and subsequent lactic acidosis, which contributes to an elevated anion gap 1. The mechanisms behind this process involve:
- Direct mitochondrial damage by ferrous iron, disrupting cellular metabolism and leading to lactic acid production
- Cellular damage in the liver and other organs, further impairing metabolism and acid-base balance
- Volume depletion due to vomiting and diarrhea, worsening metabolic derangements When treating iron overdose, clinicians should monitor acid-base status along with serum iron levels, as the development of metabolic acidosis indicates significant toxicity and may help guide management decisions, including the potential need for chelation therapy with deferoxamine 1. Key points to consider in the management of iron overdose include:
- Monitoring acid-base status and serum iron levels
- Recognizing the correlation between anion gap acidosis and severe toxicity
- Considering chelation therapy with deferoxamine in cases of significant toxicity
- Being aware of the potential for iron overload in dialysis patients, which may silently increase complications without creating frank clinical signs and symptoms 1.
From the Research
Iron Overdose and Anion Gap Metabolic Acidosis
- Iron overdose can cause anion gap metabolic acidosis, as evidenced by a case study where an 18-year-old female ingested 50 tablets of ferrous sulfate and developed severe anion gap metabolic acidosis 2.
- Another study reported a case of a 22-month-old male who ingested an estimated 50 ferrous sulfate tablets and developed coma, metabolic acidosis, hypovolemic and cardiogenic shock, liver failure, coagulopathy, and adult respiratory distress syndrome, including anion gap metabolic acidosis 3.
- A review of acute iron poisoning management also noted that iron salts can cause metabolic acidosis by interfering with intermediary metabolism and producing shock and reduced tissue perfusion, which can lead to anion gap metabolic acidosis 4.
- However, not all cases of iron overdose result in anion gap metabolic acidosis, as seen in a case of intravenous iron sucrose overdose where the patient's bicarbonate and anion gap were within normal limits 5.