Lead poisoning. Dark deposits of lead sulphate (known as lead lines) on the gum of a patient suffering from lead poisoning. Mild lead poisoning may lead to anaemia, as lead inactivates the enzymes associated with haem synthesis. In more severe cases, there may be some neurological damage to the motor system, epileptiform fits and colicky abdominal pain. Treatment is by the administering of a chelating agent, such as sodium calcium edetate or penicillamine.