Low level lead exposure and the development of children.

The clinical picture of childhood lead poisoning has changed dramatically over the past 20 years. Acute symptomatic lead poisoning, once a common problem, is now a rare event. Lead encephalopathy is even rarer. Most pediatric residents will not see a case of acute plumbism during their training; few will encounter the problem in their career. At the same time, epidemiologic studies from around the world of the effects of lead on children have demonstrated behavioral and cognitive deficits in the absence of symptoms, at levels of blood lead once considered harmless. Traditional treatments with chelating agents are ineffective at these levels of lead in blood. As a result the principal domain of lead toxicity has shifted from the clinic and hospital to the public health arena, where the effects of lead at clinically silent doses on child development remains a major issue.