Iron

1. THE 2-MINUTE PHYSIOLOGY (Rapid Pathophysiology)

• Direct Corrosive Injury: Acute ingestion of iron salts is highly caustic to the gastrointestinal mucosa, directly driving the early clinical presentation of severe nausea, vomiting, abdominal pain, and bloody diarrhea.
• Cellular Asphyxiation & Vasodilation: Systemically absorbed free iron acts as a potent, direct vasodilator that increases capillary permeability and promotes venous pooling, rapidly leading to distributive shock and hemodynamic instability. At the cellular level, circulating free iron enters the mitochondria and disrupts oxidative phosphorylation, forcing the body into anaerobic metabolism and generating a profound, high anion gap metabolic (lactic) acidosis.

2. THE BEDSIDE ACTION PLAN (Rapid ER Management)

• Initial Resuscitation (ABCs): Immediately establish large-bore intravenous access and administer aggressive IV crystalloid fluid boluses to counter the third-spacing and vasodilatory shock.
• Targeted Decontamination: Administer Whole Bowel Irrigation (WBI) with polyethylene glycol to mechanically flush the heavy metal out of the GI tract. Do not use activated charcoal, as it is entirely ineffective at binding elemental metals. Gastric lavage is similarly not recommended as heavy iron pills form concretions and easily bypass or clog the lavage tube.
• Antidotal Therapy (Chelation): Administer Deferoxamine, the specific chelating agent that binds free serum iron into a water-soluble complex (ferrioxamine) for renal excretion.
• Indications: Initiate deferoxamine immediately in patients displaying systemic toxicity (altered mental status, hemodynamic instability, severe metabolic acidosis) or in those with a peak serum iron concentration >500 mcg/dL.
• Duration limits: Continue deferoxamine for a maximum of 24 hours.
• Urine Monitoring: Place a Foley catheter to monitor urine output and watch for the classic "vin rosé" (reddish-pink) color change that indicates the successful urinary excretion of the iron-deferoxamine complex.

3. THE DIAGNOSTIC GRID (Differential Diagnosis & Workup)

• The "Can't-Miss" Mimics:
• Colchicine Toxicity: Presents with identical severe, hemorrhagic gastroenteritis and rapid progression to multiorgan failure and shock.
• Salicylate Overdose: Causes profound metabolic acidosis and GI upset, but is distinguished by an initial primary respiratory alkalosis and tinnitus.
• Other Heavy Metals / Caustics: Arsenic and inorganic mercury poisoning also cause bloody diarrhea and rapid cardiovascular collapse.
• Prioritized Diagnostic Workup:
• Serum Iron Level: Draw at 4 to 6 hours post-ingestion to capture the peak absorption level.
• Acid-Base Status: Obtain an ABG or VBG alongside a basic metabolic panel to quantify the anion gap metabolic acidosis, which is a key trigger for antidotal therapy.
• CBC and Glucose: Screen for hyperglycemia and moderate leukocytosis, which complete the classic laboratory triad of significant iron toxicity.
• Hepatic Panel: Iron is highly hepatotoxic; monitor transaminases for acute hepatic failure.

4. THE VISUAL BOARD (ECG / POCUS / Imaging)

• The Abdominal Radiograph (KUB): This is the definitive visual study required in the early triage of an iron overdose. The emergency resident must actively look for radiopaque pills coalesced in the stomach or scattered throughout the bowel. Visualizing these tablets confirms the ingestion and establishes the immediate need for aggressive Whole Bowel Irrigation (WBI).

5. THE SCORING MATRIX (Risk Stratification & Guidelines)

• The Systemic Toxicity Triggers: The clinical algorithm explicitly defines systemic toxicity by the presence of acidosis, altered mental status, or hemodynamic instability. Any one of these findings mandates immediate deferoxamine therapy, regardless of the pending serum iron level.
• The Discharge Criteria: If a patient remains completely asymptomatic at 6 to 8 hours post-ingestion, maintains a normal acid-base status, and has a peak serum iron level <500 mcg/dL, they may be medically cleared and safely discharged.

6. THE DANGER ZONE (Pitfalls & Critical Actions)

• The Decontamination Trap: Pitfall: Reflexively ordering activated charcoal for an intentional overdose. Critical Action: Recognize that activated charcoal does not adsorb elemental iron. Rely exclusively on WBI to clear the gastrointestinal burden when radiopaque pills are confirmed.
• The Prolonged Antidote Pitfall: Pitfall: Running the deferoxamine infusion indefinitely until the serum iron level reads zero. Critical Action: The infusion must be strictly capped at a maximum of 24 hours. Prolonged deferoxamine administration is highly associated with the development of fatal Acute Respiratory Distress Syndrome (ARDS) and unique susceptibility to Yersinia enterocolitica sepsis.

7. MCQ MASTERCLASS (Written Exam Tips)

• Classic Toxidrome Triad: Board questions frequently test the classic laboratory findings of severe iron poisoning: Anion gap metabolic acidosis, hyperglycemia, and leukocytosis. If a vignette features a child with bloody diarrhea and these three labs, the answer is iron.
• Buzzword: "Vin rosé urine" → Exam Answer: Indicates the presence of the ferrioxamine complex, confirming the deferoxamine antidote is actively chelating and excreting the iron.
• Distractor Options: An option will frequently suggest "gastric lavage" or "syrup of ipecac" for heavy iron pill concretions. Correction: These are strictly incorrect as they fail to remove the heavy tablets; the correct answer is Whole Bowel Irrigation (WBI).

8. THE BOARDROOM SCRIPT (OSCE & Oral Board Tips)

• The Initial Resuscitation: "The patient is presenting with hemorrhagic gastroenteritis and impending shock. I am immediately securing two large-bore IVs for aggressive crystalloid resuscitation. I will order a STAT abdominal radiograph to visualize radiopaque pills, alongside an acid-base status and a 4-hour serum iron level."
• The Decontamination Pivot: "Because the abdominal X-ray shows a significant pill burden in the stomach, and knowing that activated charcoal is ineffective for elemental metals, I am ordering immediate Whole Bowel Irrigation (WBI) with polyethylene glycol via nasogastric tube."
• The Definitive Action: "The patient's VBG demonstrates a high anion-gap metabolic acidosis, meeting the criteria for systemic toxicity. I am initiating an IV deferoxamine infusion immediately. I will place a Foley catheter to monitor for the 'vin rosé' urine color change, admit the patient to the Intensive Care Unit, and ensure the antidote is discontinued within 24 hours to prevent ARDS."