Iron Ingestion

Aka: Iron Ingestion, Iron Poisoning, Acute Iron Toxicity, Acute Iron Poisoning, Iron Overdose

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II. Precautions

  1. Iron supplements in overdosage may be lethal in children (FDA black box warning)
    1. Iron supplements and Prenatal Vitamins are the most common U.S. sources for pediatric Iron Poisoning
  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
      1. Ingestions >20 mg/kg are associated with more significant toxicity
    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

III. Findings: Iron Toxicity

  1. Phase 1: Gastrointestinal (0.5 to 6 hours)
    1. Abdominal Pain
    2. Nausea and Vomiting
    3. Diarrhea
    4. Hematemesis
    5. Upper Gastrointestinal Bleeding (e.g. Melana)
    6. Lethargy
  2. Phase 2: Latent Period (6 to 24 hours)
    1. Gastrointestinal symptoms improve
    2. Metabolic Acidosis with Anion Gap may be present
    3. Lethargy may be present in severe cases
    4. Hypotension may be present (volume depletion)
  3. Phase 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. Phase 4: Hepatic (12-96 hours, liver injury and disrupted Energy Metabolism)
    1. Hepatotoxicity (onset within 48 hours)
    2. Hepatic Failure
    3. Jaundice
    4. Hypoglycemia
    5. Coagulopathy
  5. Phase 5: Delayed (2-4 weeks)
    1. Pyloric or duodenal scarring and stenosis
    2. Gastric outlet obstruction or Small Bowel Obstruction (2-8 weeks)

IV. Labs

  1. See Overdose for Unknown Ingestion evaluation
  2. Serum Iron levels
    1. Background
      1. Iron levels predict severity of ingestion (but poor correlation with symptoms)
      2. Free, circulating Serum Iron rises when iron levels overwhelm iron binding Proteins
    2. Serum Iron levels <350 mcg/dl
      1. When drawn 3 to 5 hours after ingestion are considered reassuring (typically associated with benign course)
    3. Serum Iron 300 to 500 mcg/dl
      1. Primarily signficant gastrointestinal symptoms with mild systemic toxicity
    4. Serum Iron 500 to 1000 mcg/dl
      1. Moderate systemic toxicity
    5. 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 or Hyperglycemia may be present (but does not predict toxicity)
    2. Metabolic Acidosis with Anion Gap (strongest predictor of toxicity)
    3. Liver Injury (phase 4) with elevated Liver Function Tests, Serum Bilirubin
    4. Prerenal Azotemia may be present (with increased Blood Urea Nitrogen)
  5. Coagulation Studies (INR, PTT)
    1. Increased INR in severe liver injury (phase 4)

V. Imaging

  1. Abdominal XRay
    1. Radiopaque iron may be seen in Stomach
    2. Consider after Gastric Decontamination (e.g. Whole Bowel Irrigation)
      1. May identify residual radiopaque iron and pill concretions

VI. Management

  1. ABC Management
  2. Contact poison control
  3. Initial emergent supportive care for Hypovolemic Shock (aggressive fluid Resuscitation)
    1. Crystalloid (NS or LR) replacement for Hypovolemia
    2. Transfuse pRBCs
    3. Correct Metabolic Acidosis (starting with fluid Resuscitation)
  4. Discuss Gastric Decontamination with poison control
    1. Whole Bowel Irrigation may be recommended in large acute ingestions
      1. See Whole Bowel Irrigation for contraindications
      2. Obtain early abdominal xray to estimate gatrointestinal iron
      3. Perform for at least >4 hours (typically 6-10 hours) and until rectal effluent clear
      4. Polyethylene Glycol (typically via Nasogastric Tube)
        1. Adults (and children age >=13 years): 1.5 to 2 L/h for 6 to 10 hours
        2. Children: 25 ml/kg/h for 6 to 10 hours
          1. Age 9 months to 6 years: 250 to 500 ml/hour
          2. Age 6 to 12 years: 1000 ml/hour
    2. Avoid Activated Charcoal (ineffective in iron absorption, does not bind iron salts)
    3. Most children vomit after Iron Ingestion with partial clearance of iron
    4. Consider Nasogastric Tube with Normal SalineStomach lavage if very early presentation after ingestion
      1. May decrease Stomach mucosal injury from iron, and breakdown pill concretions
  5. Deferoxamine Chelation (Desferal)
    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. Sart 5 mg/kg/hour and observe for Hypotension over the subsequent hour
        1. Coadminister with crystalloid (prevents Hypotension, helps clear ferioxamine complexes from serum)
      2. Titrate up to 15 mg/kg/h while closely observing for Hypotension
        1. May require further titration by 5 to 10 mg/kg/hour every 2 to 4 hours
        2. Some cases have used doses as high as 50 mg/kg/h in very severe Poisonings
        3. Maximum total dose 360 mg/kg/day (6 grams/day)
      3. Obtain iron levels every 2-3 hours
      4. Anticipate Urine Color change
        1. Orange red color (vin rose urine) reflects iron-deferoxamine complex excretion
        2. Expect Urine Color to return to normal as Serum Iron normalizes
      5. Other markers of improvement
        1. Metabolic Acidosis resolves
      6. Indications to Discontinue Deferoxamine (consult poison control)
        1. Iron level <350 mcg/dl (62 mmol/L) AND
        2. Asymptomatic AND
        3. Urine Color normalizes AND
        4. Metabolic Acidosis resolves
      7. Complications
        1. Deferoxamine may increase risks of YersiniaSepsis

VII. Prognosis

  1. Children who are fully asymptomatic at 6 hours after Iron Ingestion are expected to have a benign course
  2. Metabolic Acidosis and significant radiopaque iron on imaging are associated with more significant ingestions
  3. Serum Iron at 3-5 hours after ingestion
    1. Serum Iron <300-350 mcg/dl predicts benign course
    2. Serum Iron >500 mcg/dl predicts severe course

VIII. Complications

  1. Hypovolemic Shock
  2. Upper Gastrointestinal Hemorrhage
  3. Acute Renal Failure
  4. Hepatic Failure

IX. References

  1. (2016) CALS Manual, 14th ed, I-137
  2. Gossman (2016) Emergency Medicine Oral Board Review, p. 207-9
  3. Okuda (2019) Emergency Medicine Oral Board Review, p. 38-43
  4. Tagliaferro (2023) Crit Dec Emerg Med 37(1): 21-9

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