Cyanide Poisoning

Key points

• • Cyanide binds to the ferric iron of cytochrome c oxidase in the mitochondria, blocking the electron transport chain so cells cannot use oxygen.
• • Because oxygen is not extracted from the blood, the venous blood may stay bright red and the skin look pink rather than blue, though these signs are unreliable.
• • A bitter-almond smell may be noted on the breath or at autopsy, although many people are genetically unable to detect it.
• • The features come on very fast: headache, breathlessness, giddiness, convulsions and death from failure of breathing.
• • Sources include industrial salts, certain plant seeds such as bitter cassava and apricot kernels, and the fumes of burning plastics.