Iron is an essential heavy metal that is included in many over-the-counter multivitamin and mineral supplements and is used therapeutically in higher doses to treat or prevent iron deficiency anemia. When taken at the usual recommended daily allowance , iron has little or no adverse effect . In high doses and in intentional or accidental overdoses, iron causes serious toxicities.

Range of toxicity 

▫️Ingestions of 20 to 60 mg/kg of elemental iron have a low potential for serious toxicity. 

▫️Ingestions ≥60 mg/kg of elemental iron are associated with serious toxicity and death

The manifestations of iron toxicity after ingestion are typically described in five phases:

▪️ Early gastrointestinal (GI) symptoms: 30 minutes to 6 hours after ingestion 

▪️Latent: 6 to 24 hours after ingestion, may have poor perfusion, tachypnea, tachycardia. 

▪︎Shock and persistent elevated anion gap metabolic acidosis: 6 to 72 hours after ingestion

▪︎Delayed hepatotoxicity/hepatic necrosis: 12 to 96 hours after ingestion

▪︎Remote bowel obstruction (usually gastric outlet obstruction): 2 to 8 weeks after ingestion

The progression of these phases may occur rapidly after large oral overdoses. Therefore, the clinical phase should be determined by the patient’s clinical and laboratory manifestations , not by the time since the ingestion.

Treatment

Emergency and Supportive Measures 

☆Supportive care with intravenous fluid hydration is usually sufficient for mild poisonings. Activated charcoal is not effective for iron ingestions 

☆Whole bowel irrigation to remove unabsorbed pill

☆Specific Treatment : Deferoxamine can be used to chelate iron. Patients who are symptomatic should receive deferoxamine regardless of their iron level. In acute or chronic iron toxicity, chelation therapy with deferoxamine is indicated for patients with serum iron levels >350 mcg/dL who have evidence of toxicity, or levels of > 500 mcg/dL regardless of signs or symptoms . In patients with significant clinical manifestations of toxicity, chelation therapy should not be delayed while one awaits serum iron levels

Source:

Uptodate 2023 

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