Iron, Lead & Heavy Metal Poisoning

Also known as Iron overdose · Lead poisoning · Heavy metal poisoning · Deferoxamine · Chelation · Succimer · Dimercaprol

The heavy-metal poisonings — the iron (the four phases, the deferoxamine), the lead (the abdominal pain, the microcytic anaemia with the basophilic stippling, the peripheral neuropathy, the encephalopathy; the succimer, the EDTA, the dimercaprol), the arsenic (the garlic breath, the GI, the neuropathy, the QT), the mercury (the neuro, the tremor, the GI), the cadmium (the pneumonitis). The common theme the chelation (the deferoxamine for the iron; the dimercaprol/BAL, the succimer/DMSA, the CaNa2EDTA for the lead and the others).

medium20 referencesUpdated 19 Aug 202613 min readSource-verified · Oct 2026

Checked against its sources on 14 Oct 2026

Practise this topic

8 MCQs

The one-paragraph exam answer

The heavy-metal poisonings are unified by chelation as the specific therapy, but each metal has its own staged course and its own chelation rules. Iron runs a five-stage course (gastrointestinal, the deceptive quiescent window, shock and metabolic acidosis, hepatic failure, and late gastric-outlet obstruction); triage is by mg per kg of elemental iron, the tablets are radiopaque, charcoal does not bind them, and deferoxamine produces the vin-rose urine. Lead produces abdominal pain, a microcytic anaemia with basophilic stippling, wrist-drop neuropathy, and encephalopathy — succimer oral, CaNa2EDTA IV, and dimercaprol IM first in the encephalopathic (never disodium EDTA). Arsenic gives garlic breath, rice-water diarrhoea, and QT prolongation with torsades. Mercury comes in three forms: elemental and organic get succimer (NEVER dimercaprol, which redistributes to the brain), inorganic salts tolerate dimercaprol.^[2]^[1]

Meet the patient

A 3-year-old girl (14 kg) is brought to the emergency department three hours after the babysitter found her with an open bottle of prenatal ferrous sulphate 325 mg tablets, about thirty missing. She has vomited three times, including tablet fragments, and is now drowsy. The serum iron is pending; an abdominal X-ray shows multiple radiopaque tablets in the stomach.^[4]^[6]

The two traps in that vignette are the ones that kill: the elemental-iron dose decides the danger (not the number of tablets), and the apparent improvement at six hours is the deceptive quiescent window that precedes the shock and acidosis. Charcoal will not help her; whole-bowel irrigation will; and the vin-rose urine will tell you the deferoxamine is working. Hold the five-stage course and the chelation rules and the rest follows.^[1]^[4]

References20Show

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