- Iron poisoning is a common and potentially fatal ingestion.
- Toxicity depends on the amount of elemental iron ingested, although tolerable and lethal concentrations are not firmly established.
- Doses of <20 mg/kg of elemental iron are generally not symptomatic, of 20 to 60 mg/kg are variably symptomatic, and of >60 mg/kg are severely toxic and potentially fatal.
- Accounts for about 2–4% of all exposures in children and adolescents
- Can be divided into unintentional (younger children) and intentional (adolescents)
- Incidence: almost 11,000 iron exposures per year in children <6 years old in United States, based on the 2015 American Association of Poison Control Centers Annual Report
- Many factors contribute to the incidence of iron ingestion:
- High-iron preparations such as prenatal vitamins are readily available (prenatal vitamins contain the highest amount of iron per tablet).
- Many preparations are attractive and candy-like.
- Caregivers often fail to appreciate the danger of overdose from vitamins and pure iron preparations.
- Although vitamin ingestions are increasing, the incidence of fatal iron ingestions has declined since the 1990s, perhaps due to changes in package labels and child-resistant packaging.
- Birth of a sibling, including up to 1 year after (increased availability of prenatal vitamins)
- Among unintentional ingestion, almost all serious mortality and morbidity is in children <5 years of age (ingestion of adult iron formulations).
- Parental education: Keep all medications and vitamins out of reach in child-resistant packaging.
- In 1997, federal regulations required unit-dose packaging (blister packs) for all iron preparations with >30 mg of elemental iron per dose.
- Significant decrease in iron ingestion–related deaths after regulations
- The United States Food and Drug Administration (FDA) removed regulations in 2003, although many manufacturers voluntarily continue this type of packaging.
- Iron directly damages cells, interfering with aerobic respiration. The primary systems affected by iron are the gastrointestinal (GI) tract, including the liver, and the cardiovascular system.
- There are five classic stages of iron poisoning:
- Stage I (GI phase)
- Occurs up to 6 hours post ingestion
- Characterized by GI mucosal injury, leading to abdominal pain, vomiting, diarrhea, and GI bleeding (hematemesis or hematochezia)
- Metabolic acidosis may be present, and death may be caused by capillary leakage and hypovolemic shock.
- Stage II (latent)
- 6 to 24 hours after ingestion
- Relative stability and temporary resolution of GI symptoms
- Does not always occur
- Although there may be improvement of symptoms, there is continued cellular toxicity and metabolic acidosis.
- Stage III (shock)
- 12 to 24 hours after ingestion (can occur earlier with high dose ingestions)
- Systemic symptoms: hemodynamic instability, shock, metabolic acidosis
- Coagulopathy is common and worsens GI bleeding (can occur even without hepatotoxicity).
- Vasodilation can lead to hypovolemia, and myocardial injury can lead to cardiogenic shock.
- Stage IV (hepatotoxicity)
- Within 48 hours after ingestion
- May result in liver failure
- Stage V (late)
- 2 to 8 weeks post ingestion
- Gastric injury may result in strictures, leading to vomiting and potentially gastric outlet obstruction.
- Stage I (GI phase)
There's more to see -- the rest of this topic is available only to subscribers.