Pathophysiology

The primary mechanism for iron-induced tissue damage is free radical production and lipid peroxidation 

• Local toxicity: mucosal damage to GI mucosa leading to pain, vomiting, diarrhea, GI bleeds

• Systemic toxicity: damage to the cardiovascular system and liver leading to shock, liver failure, and multiorgan dysfunction.

Toxic Dose:

• <20 mg/kg of elemental iron are often asymptomatic

• >60 mg/kg of elemental iron can be associated with serious toxicity

Common examples: Adult ferrous sulfate tablets and prenatal vitamins

Presentation

Diagnosis

Consult Poison Control: 1800-222-1222

• Serum iron concentration (SIC) 4-6 hours after ingestion. Sustained release or enteric-coated preparations may have delayed absorption so repeat SIC at 6-8 hours

• CMP to assess electrolytes, liver, and renal function

• Consider blood gas, lactate, PT/PTT, T&S if concerned about acidosis or coagulopathy

• Screen for co-ingestions

• EKG

• Abdominal radiograph:  The presence of radiopaque pills in the stomach confirms the ingestion of iron and can help dictate if gastric decontamination is indicated. Be mindful of false negatives as not all formulations of iron will be radiopaque.

Management

1. IV fluid bolus and maintenance fluids

2. Gastric decontamination

1. Charcoal is NOT indicated in iron ingestions as it binds iron poorly

2. Whole bowel irrigation is indicated for patients with a large number of pills visualized on abdominal radiography

3. Deferoxamine: A chelating agent that binds ferric iron that is then renally excreted

   1. Indications:

      • SIC >500 mcg/dL

      • Elevated anion gap metabolic acidosis

      • Severe symptoms

      • Abdominal radiograph reveals a significant number of pills

   2. Adverse effects:

      • Hypotension during initial administration due to histamine release. Avoid by providing vigorous fluid resuscitation.

      • ARDS can develop in those who receive continuous infusions for >32 hours.

4. Monitoring

   1. Ingestions <60 mg/kg or those with a 4-6 hour iron level <500 mcg/dL may be observed for 6 hours and discharged if stable

   2. Ingestions <40 mg/kd do not require further evaluation or treatment unless significantly symptomatic or suicidal

References