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Iron Ingestion

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Iron Ingestion, Iron Poisoning, Acute Iron Toxicity, Acute Iron Poisoning, Iron Overdose

  • Precautions
  1. Iron supplements in overdosage may be lethal in children (FDA black box warning)
  2. Iron toxicity after acute ingestion is difficult to gauge
    1. Variable effects depending on formulation (Serum Iron levels are better correlates)
    2. Toxic Overdoses may occur with ingestions as low as 10 to 20 mg/kg elemental iron
    3. Elemental iron varies by formulation (see Iron Supplementation)
      1. Ferrous Fumarate contains 33% elemental iron
      2. Ferrous Sulfate contains 20% elemental iron
      3. Ferrous Gluconate contains 12% elemental iron
  • Pathophysiology
  • Iron Toxicity
  1. Stage 1: Gastrointestinal (0.5 to 6 hours)
    1. Abdominal Pain
    2. Nausea and Vomiting
    3. Diarrhea
    4. Hematemesis
    5. Melana
    6. Lethargy
  2. Stage 2: Latent Period (6 to 24 hours)
    1. Metabolic Acidosis may be present
    2. Lethargy may be present
    3. Hypotension may be present
  3. Stage 3: Systemic Toxicity and Shock (6-72 hours)
    1. Cyanosis
    2. Hypovolemia and Hypotension (shock)
    3. Lactic Acidosis
    4. Lethargy
    5. Restlessness
    6. Disorientation to Coma
    7. Convulsions
    8. Coagulopathy
  4. Stage 4: Hepatic (12-96 hours)
    1. Hepatotoxicity (onset within 48 hours)
    2. Hepatic Failure
    3. Jaundice
    4. Hypoglycemia
    5. Coagulopathy
  5. Stage 5: Delayed (2-4 weeks)
    1. Gastric outlet obstruction or Small Bowel Obstruction (2-8 weeks)
    2. Pyloric scarring
  • Labs
  1. See Overdose for Unknown Ingestion evaluation
  2. Serum Iron levels predict severity of ingestion
    1. Serum Iron 300 to 500 mcg/dl
      1. Primarily signficant gastrointestinal symptoms with mild systemic toxicity
    2. Serum Iron 500 to 1000 mcg/dl
      1. Moderate systemic toxicity
    3. Serum Iron >1000 mcg/dl
      1. Severe toxicity and morbidity
  3. Complete Blood Count
    1. Leukocytosis may be present (but does not predict toxicity)
  4. Comprehensive Metabolic Panel (with Electrolytes, Liver Function Tests, Renal Function tests)
    1. Hypoglycemia may be present (but does not predict toxicity)
  5. Coagulation Studies (INR, PTT)
  • Management
  1. ABC Management
  2. Contact poison control
  3. Initial emergent supportive care for shock
    1. Crystalloid (NS or LR) replacement for Hypovolemia
    2. Transfuse pRBCs
    3. Correct Metabolic Acidosis
  4. Discuss Gastric Decontamination with poison control
    1. Whole Bowel Irrigation may be recommended
    2. Polyethylene glycol (typically via Nasogastric Tube)
      1. Children: 25 ml/kg/h (typically 250-500 ml/h) for 6-10 hours
      2. Adults: 2 L/h for 6-10 hours
    3. Avoid Activated Charcoal (ineffective in iron absorption)
  5. Deferoxamine Chelation
    1. Indications (once hemodynamically stable)
      1. Vomiting, diarhea and signs of shock
      2. Peak iron level >500 mcg/dl (90 mmol/L)
      3. Peak iron level >350 mcg/dl AND symptomatic (including persistent Vomiting)
      4. Pills seen on abdominal XRay
      5. Metabolic Acidosis
    2. Protocol
      1. Deferoxamine started at 5 mg/kg/h and observe for Hypotension over the subsequent hour
      2. May titrate to a maximum of 15 mg/kg/h while closely observing for Hypotension
        1. Some cases have used doses as high as 50 mg/kg/h in very severe Poisonings
      3. Obtain iron levels every 2-3 hours
        1. Discontinue Deferoxamine when iron level <350 mcg/dl (62 mmol/L) and asymptomatic
      4. Anticipate Urine Color change
        1. Orange red color (vin rose urine) reflects iron-deferoxamine complex excretion
  • Prognosis
  1. Serum Iron at 2-6 hours after ingestion
    1. Serum Iron <300 mcg/dl predicts benign course
    2. Serum Iron >500 mcg/dl predicts severe course
  • References
  1. Gossman (2016) Emergency Medicine Oral Board Review, p. 207-9
  2. Okuda (2019) Emergency Medicine Oral Board Review, p. 38-43
  3. (2016) CALS Manual, 14th ed, I-137