SN3 SHORT NOTE 5M ★ High-yield

Describe iron poisoning with its stages and management.

Forensic Medicine · 2nd Professional — Para-Clinical

Sources and Mechanism

Iron poisoning is predominantly a poisoning of children, and is one of the commonest causes of fatal accidental poisoning in that age group. The reason is simple: ferrous sulphate tablets are brightly coloured, sugar-coated and look like sweets, and they are present in almost every household in India because they are distributed free to pregnant women and to children under the anaemia programme
Toxicity depends on the elemental iron, not on the salt weight — ferrous sulphate is about 20% elemental, fumarate 33% and gluconate 12%. Below 20 mg/kg of elemental iron is generally non-toxic; above 60 mg/kg is severe and potentially lethal
Mechanism — a direct corrosive action on the gastric and intestinal mucosa; and systemically, free iron overwhelms transferrin, enters cells, and acts as a mitochondrial poison, uncoupling oxidative phosphorylation and generating free radicals — producing metabolic acidosis, vasodilatation and hepatocellular necrosis

Stage	Time	Features
I — Gastrointestinal	0 to 6 hours	Vomiting and diarrhoea, characteristically with haematemesis and melaena from the corrosive action; abdominal pain; and in severe cases early shock. The severity of this phase predicts the outcome
II — latent ("the false calm")	6 to 24 hours	Apparent recovery. The gastrointestinal symptoms settle and the child looks better, while iron is being taken up into the cells. This IS the dangerous phase, and children are discharged in it
III — Shock and metabolic acidosis	12 to 48 hours	Profound shock, high anion gap metabolic acidosis, hepatic necrosis, coagulopathy, renal failure, convulsions and coma
IV — Hepatic	2 to 5 days	Fulminant hepatic failure with jaundice, hypoglycaemia and encephalopathy
V — Late sequelae	2 to 6 weeks	Pyloric and intestinal stricture from healing of the corrosive injury, with gastric outlet obstruction

CLINICAL PEARL

The latent phase is why children die of iron. The vomiting settles, the child looks well, the parents are reassured and everyone goes home — and twelve hours later the child is in shock with a profound metabolic acidosis. Any child with a significant ingestion is admitted and observed through the false calm, whatever they look like at four hours.

Investigation and Treatment

Abdominal radiograph — iron tablets are radio-opaque and are seen in the stomach and bowel, which confirms the ingestion, indicates the quantity and guides decontamination. A negative film does not exclude it, since liquid preparations and chewable tablets are not opaque and tablets dissolve
Serum iron at 4 to 6 hours; levels above about 500 micrograms per decilitre indicate severe poisoning. A low level late does not exclude poisoning, since iron moves rapidly into the tissues. Also check the anion gap, lactate, glucose, liver function and coagulation
Decontamination — activated charcoal does not adsorb iron and is useless; whole bowel irrigation with polyethylene glycol is the method of choice where tablets are visible on the film; and gastric lavage may help very early
Antidote — desferrioxamine, by intravenous infusion, which chelates free iron and is excreted as ferrioxamine, turning the urine a characteristic "vin rose" pink — used to confirm that chelation is occurring and to monitor the endpoint
Supportive care — aggressive fluid resuscitation, correction of acidosis, blood products for coagulopathy, and management of hepatic failure

Applied Aspects

Admit and observe every significant paediatric ingestion through the latent phase; the child who looks well at six hours may be shocked at eighteen
Radiograph the abdomen; visible tablets confirm the ingestion, indicate the burden, and are the indication for whole bowel irrigation
Do not give activated charcoal for iron — it does not bind it, and giving it wastes time and risks aspiration
Calculate the elemental iron, not the tablet weight; the difference is threefold between preparations and determines whether treatment is needed at all
Start desferrioxamine on clinical grounds in a severely poisoned child rather than waiting for the level; and watch the urine colour
Advise on storage at discharge; iron tablets look like sweets and are in every Indian household under the anaemia programme, and child-resistant storage is the only real prevention
Warn about late stricture, and arrange follow-up at several weeks; gastric outlet obstruction after apparent recovery is a recognised and avoidable readmission
Iron tablets are distributed free under the anaemia programme, which is why they are in almost every Indian household within a child reach

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