Iron Poisoning
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Direct answer
Iron poisoning is toxicity from iron salts, most often in young children who swallow iron tablets, beginning with corrosive gastroenteritis that can progress to shock, metabolic acidosis and hepatotoxicity. A deceptive latent period often follows the early phase, so an apparently well child can deteriorate later. Serum iron levels, abdominal radiographs for radio-opaque tablets and deferoxamine chelation guide management.
What you must remember
- Staged course: early gastrointestinal injury, a latent period of apparent recovery, systemic shock and acidosis, hepatic failure, and late gastric outlet obstruction, with books differing on exact timings.
- Serum iron: levels above roughly 350 to 500 micrograms per decilitre signal serious toxicity, and the value is read together with the clinical picture and the time since ingestion.
- Abdominal radiograph: radio-opaque tablets can be seen in the stomach or bowel, which helps estimate the amount ingested, but a clear film does not exclude significant ingestion.
- Deferoxamine: a chelator for ferric iron, indicated for serious serum levels or systemic toxicity, and the urine may turn vin rosé in colour during treatment.
- Activated charcoal: does not adsorb iron and should not be used for this purpose.
- Whole-bowel irrigation: used for significant ingestions of radio-opaque tablets, with the airway protected.
- Systemic toxicity: shock, metabolic acidosis with raised lactate, coagulopathy and deranged glucose need active resuscitation.
- Indian context: iron-containing preparations, including multivitamin and haematinic tablets, are a common accidental poisoning in toddlers.
The staged course of iron toxicity
Iron toxicity moves through recognisable phases, and each phase carries a different danger.
| Stage | Typical timing | Key features |
|---|---|---|
| 1. Gastrointestinal injury | First hours | Vomiting, diarrhoea, haematemesis, abdominal pain |
| 2. Latent phase | After the first phase | Apparent improvement, sometimes no symptoms |
| 3. Systemic toxicity | Several hours to a day | Shock, metabolic acidosis, coagulopathy, deranged glucose |
| 4. Hepatic failure | Days later | Raised transaminases, jaundice, liver failure |
| 5. Gastric outlet obstruction | Weeks later | Scarring and pyloric stenosis |
Clinicians must not be reassured by the latent phase, because the patient can slide into shock after apparent recovery. Management therefore follows the stage and the serum iron level rather than the symptoms present at arrival.
Treatment is directed at reversing hypovolaemia, correcting acidosis and chelating iron with deferoxamine when indicated, ideally under poison centre guidance.
Systemic toxicity is the stage most likely to prove fatal, so early transfer to a unit with intensive care and toxicology support is advised. Serial lactate, glucose, coagulation and liver tests guide the timing of each step.
Where the exam tries to catch you
Most lost marks come from trusting the latent phase or from using charcoal for iron.
- Trap: discharging a child once vomiting stops and the latent phase begins Correct: the latent phase is deceptive, and shock or acidosis can appear later, so observation and serum iron are needed.
- Trap: giving activated charcoal to absorb iron Correct: charcoal does not bind iron, so whole-bowel irrigation or chelation is used instead.
- Trap: assuming a normal abdominal radiograph excludes ingestion Correct: not all iron preparations are radio-opaque, so a clear film does not rule out significant ingestion.
- Trap: using deferoxamine for every ingestion Correct: chelation is reserved for raised serum iron or systemic toxicity, under poison centre guidance.
Frequently asked questions
Why is activated charcoal not used in iron poisoning?
Activated charcoal is not used in iron poisoning because it does not adsorb iron salts effectively. Whole-bowel irrigation for radio-opaque tablets or chelation with deferoxamine is used instead, depending on the severity of the ingestion.
What does an abdominal radiograph show in iron poisoning?
An abdominal radiograph can show radio-opaque iron tablets in the stomach or bowel, which helps estimate the amount ingested and guide whole-bowel irrigation. A clear film does not exclude significant ingestion, because not all iron preparations are radio-opaque.
When is deferoxamine indicated in iron poisoning?
Deferoxamine is indicated in iron poisoning when serum iron is at a serious level, or when shock, metabolic acidosis or systemic toxicity is present. It chelates ferric iron, and the urine may turn vin rosé in colour during treatment.
Why is the latent phase in iron poisoning dangerous?
The latent phase in iron poisoning is dangerous because the child appears to recover after early vomiting while iron continues to injure the body. Shock, acidosis and hepatotoxicity can then appear, which is why observation is needed before any discharge.
What late complication follows severe iron poisoning?
Severe iron poisoning can cause gastric outlet obstruction weeks later, from scarring of the gut wall and pyloric stenosis. The main safeguard is early recognition and treatment of acute toxicity, before the injury becomes established.