Iron Toxicity Clinical Presentation
- Author: Clifford S Spanierman, MD; Chief Editor: Asim Tarabar, MD more...
Gastrointestinal (GI) manifestations such as vomiting and diarrhea (especially when hemorrhagic) are an important feature of acute iron toxicity. Pediatric patients who are alert and not vomiting most likely did not ingest a toxic dose of iron; in adults, however, abdominal pain and vomiting may be absent. More than four episodes of vomiting suggests significant iron toxicity. Hemorrhagic gastroenteritis, even in the absence of a history of iron ingestion, should raise suspicion for iron toxicity.
Iron poisoning is often classified into five distinct stages, as follows:
- Stage 1 - Gastrointestinal (GI)
- Stage 2 - Latent
- Stage 3 - Metabolic/cardiovascular
- Stage 4 - Hepatic
- Stage 5 - Delayed
Understanding the course of poisoning is important. In particular, the second stage may lure the physician into a false sense of security and result in premature and inappropriate discharge of a patient.
Features of stage 1 iron toxicity are as follows:
- This stage usually occurs within 6 hours after exposure
- Nausea and diarrhea, often accompanied by abdominal pain, characterize this stage
- When the intoxication is severe, a hemorrhagic component is observed in conjunction with gastroenteritis
- The combination of GI fluid loss and blood loss, with additional third-spacing, may result in hypovolemia or shock
- Fatality occurs in a significant percentage of patients during this stage
Features of stage 2 iron toxicity are as follows:
- GI symptoms resolve, and the patient appears to improve and recover
- This deceptive phase usually occurs 6-12 hours after ingestion and may last as long as 24 hours.
- Metabolic abnormalities during this phase may include hypotension, metabolic acidosis, and coagulopathy
- Some patients skip this phase and progress directly to stage 3
Features of stage 3 iron toxicity are as follows:
- Stage 3 is characterized by metabolic acidosis and cardiovascular symptoms; the acidosis may indicate failure of organs such as the heart and kidneys
- It is hypothesized that high iron concentrations produce venous pooling and third-spacing of fluids
- Central nervous system (CNS) symptoms, usually stupor and coma, are also characteristic of stage 3
- Most deaths occur during this stage
- Stage 3 can start very early (6-8 h), depending on severity of exposure, and can last up to 2 days
Features of stage 4 iron toxicity are as follows:
- Elevated liver enzymes and bilirubin levels are commonly observed with coagulopathy, indicative of hepatic dysfunction
- Hypoglycemia may accompany liver dysfunction
Features of stage 5 iron toxicity are as follows:
- This stage is characterized by scarring of the healing GI tract; the stomach and/or intestines may be affected, resulting in gastric outlet or intestinal obstruction
- This phase usually is experienced weeks after a severe poisoning
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