HWN Suggests

Iron Toxicity

Patient may go home without work-up if: This was accidental (don’t overlook the possibility of suicidal ideation?), and ingestion was < 20 mg/kg of elemental iron, or ingestion was of Carbonyl form, or ingestion was of pediatric iron formulation, or patient has been symptom free for 6 hours after ingestion (respect vomiting… don’t just throw ondansetron at it), and no concern for co-ingestion, and confidence in care-givers.

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 Candy or Medication? – Pediatric Iron Overdose

Serum Iron Level is useful for diagnosis; should be measured at 4 hours after ingestion as peak levels occur at 4-6 hours after ingestion.

 Iron poisoning: a rusty diagnosis

The main mechanism of iron's toxicity is free radical production caused by excessive free elemental iron, resulting in widespread damage on a cellular level. At normal levels, elemental iron does not cause toxicity because it is always bound to proteins within the body, such as transferrin and ferritin.

 Management of Iron Toxicity

>20 mg/kg Gastrointestinal symptoms start, ≥40 mg/kg Current level recommended for ED referral after ingestion.

 Not Just a Vitamin: Iron Toxicity and Management

Only a serum iron is useful in assessing acute toxicity. Ferritin and TIBC have no role in overdose.

Articles of Interest

CRACKCast E157 – Iron and Heavy Metals

Activated charcoal does NOT bind iron. Whole bowel irrigation is the method of choice for decontamination in acute iron ingestions. (PEG via NG @ 500 – 2 L PER hour depending on the age) – until rectal effluent is clear. (indicated for ingestion >20mg/kg or pills on AXR).

Iron Overdose

Risk assessment is based on the amount of elemental iron ingested... Iron has local gastrointestinal effects followed by systemic effects (that do not occur without preceding GI toxicity following iron ingestion)

Iron Overdose in a Pregnant Patient

It turns out that the iron dosage on the prenatal vitamin bottles is actually the amount of elemental iron.

Iron Toxicity: Onset and Emergency Treatment

Iron poisoning is divided into four phases. The first phase occurs in the first few hours after ingestion and involves acute gastric disturbances. The effects on the GI tract are due to the corrosiveness of the iron solution and include vomiting, diarrhea and abdominal pain. The disintegration of iron supplements results in a black coloration of the vomit and stools.

Tox Silent Killers

For iron levels < 300 mcg/dL, you may observe the patient for 6 hours, and if they remain completely asymptomatic, the patient may be discharged. Initial treatment for iron toxicity is supportive care including anti-emetics and IVFs for volume loss from GI symptoms. Consider whole bowel irrigation for larger ingested quantities with visible pills in the stomach on XR (NG tube with polyethylene glycol with up to 500 cc/hr in children or up to 2L/h in adults, until rectal effluent is clear.)

Usefulness of the Total Iron Binding Capacity in the Evaluation and Treatment of Acute Iron Overdose

The TIBC fails as a marker of toxicity for several reasons. First, the laboratory methods used to measure TIBC are inaccurate in the setting of iron overload.

Resources

emDOCs

The main diagnosis of iron toxicity will be a clinical diagnosis obtained from history and laboratory data/images. Serum iron concentrations will be helpful primarily to predict toxicity and treatment efficacy. An abdominal XR may be useful to evaluate for pills or pill fragments (iron tablets are typically radiopaque). However, this will not tell you about the concentration or exact size of the ingestion.

BC Emergency Medicine Network

If radio-opaque pills are seen on X-ray, consider whole bowel irrigation.

StatPearls

Ingestion of less than 20 mg/kg of elemental iron is non-toxic. Ingestion of 20 mg/kg to 60 mg/kg results in moderate symptoms. Ingestion of more than 60 mg/kg can result in severe toxicity and lead to severe morbidity and mortality.

WikEM

Patients with asymptomatic ingestion of <20mg/kg of elemental iron only require observation x 6hr.