Heavy Metal Poisoning

Key points

• • Heavy metals such as lead, arsenic and mercury are poisons that bind to proteins and enzymes, damaging many organs, especially when exposure is long-term.
• • Lead poisoning causes abdominal colic, anaemia (with basophilic stippling of red cells), sometimes a blue line on the gums, and nerve damage such as wrist drop.
• • Lead is especially harmful to children, in whom it impairs brain development, and it can be picked up from old paint, contaminated water and some traditional remedies.
• • Arsenic poisoning causes vomiting and profuse watery diarrhoea when acute, and skin changes, weakness and nerve damage when chronic; it was historically a classic homicidal poison.
• • Mercury poisoning damages the nerves, kidneys and gums, and the brain form (as in Minamata disease) causes tremor and personality change.
• • These metals can be detected long after death in the hair, nails and bones, which makes them useful in the forensic investigation of poisoning.