Management of Acute Iron Poisoning

Abstract

Acute iron poisoning is most common in children below the age of 5 years. While there is no doubt that it may be fatal, recent surveys show that death occurs in only a very small percentage of cases and that iron salts are responsible for a small minority of fatalities due to overdosage with drugs. Similarly, the proportion of severe cases seems to have fallen over the last thirty years, possibly due to earlier and more aggressive treatment but more probably due to an increase in the number of minor exposures reported. Iron salts are directly toxic to the gastrointestinal tract causing vomiting, diarrhoea, abdominal pain and occasionally significant blood loss. They also cause metabolic acidosis by interfering with intermediary metabolism and producing shock and reduced tissue perfusion. The clinical course of acute iron poisoning is divided into 4 phases. Features of acute gastrointestinal irritation dominate the period up to 6 hours after ingestion and most patients do not develop other features or progress beyond this stage. Rarely, blood loss may be sufficient to cause hypotension. Severe poisoning is characterised by impairment of consciousness, convulsions and metabolic acidosis. The second phase, 6 to 12 hours after ingestion, is one of remission of features. Phase 3 comprises the period 12 to 48 hours from ingestion and is reached only by a small minority of patients. Recurrence or development of shock, and metabolic acidosis are usual and renal failure and features of extensive hepatocellular necrosis may develop. The last (fourth) phase, 2 to 6 weeks after ingestion, is only likely to develop in young children and is characterised by recurrence of vomiting due to gastric or duodenal stenosis caused by healing of iron-induced mucosal ulcers. Acute iron poisoning in humans has not been adequately studied and is unlikely to be so now because of the infrequent and sporadic occurrence of cases. The evidence for many conventional aspects of management is therefore unsatisfactory. Assessment of severity of poisoning is an essential prerequisite to optimum management but is difficult. The amount of elemental iron ingested is unacceptable since it is seldom known with accuracy and absorption is unpredictable because of vomiting and diarrhoea. The commonly encountered clinical features are also unreliable although it is generally accepted that coma, shock and metabolic acidosis indicate severe poisoning.(ABSTRACT TRUNCATED AT 400 WORDS)

Performance Characteristics of Three Serum Iron and Total Iron-Binding Capacity Methods in Acute Iron Overdose

“…3 ' 4 ' [9][10][11][12] More recently, others have indicated that the TIBC is not measured consistently in acute overdose situations by certain methods, one using magnesium carbonate and the other using an iron-absorbing resin, and, therefore, should not be relied on. 67 It remains to be determined whether appropriate measurement of the TIBC can facilitate correct medical decisions about chelation.…”

Near fatal iron intoxication managed conservatively

“…Features of acute gastrointestinal irritation dominate the period up to 6 h after ingestion, and most patients do not develop other features or progress beyond this stage. Hypotension may arise at this stage either due to hypovolaemia or due to blood loss 2 3 7. In the index case, it was probably due to hypovolaemia.…”

“…Acute kidney injury and hepatocellular failure may develop in a few patients during this stage. The last (fourth) phase, which usually develops in young children 2–6 weeks after ingestion, is characterised by the recurrence of vomiting due to gastric or duodenal stenosis caused by the healing of gastric erosions 2 3 7…”

“…The definitive therapy for iron poisoning is deferoxamine, an iron chelator that has been used over the past five decades as a therapeutic agent for the treatment of both acute and chronic iron overdoses 7. The recommended maximal dosage of deferoxamine is 80 mg/kg over 24 h. However, 100 mg of deferoxamine chelates only 8.5 mg of iron.…”

The efficacy of diazepam in the treatment of acute iron overload in rats

“…therapy for acute iron intoxication, we have had preliminary evidence that diazepam may reduce mortality following the administration of a lethal dose of iron. To date all attempts at decreasing morbidity and mortality from acute iron overdose have focused on gut decontamination and systemic chelation of the metal (Tenenbein 1985;Proudfoot et al 1986). The benzodiazepines have never been either proposed or tested in this condition, as there was no theoretical or hypothetical framework to rationalize such an experiment.…”