In 1991, the value for an elevated blood lead level was redefined to 10 μg per dL (0.48 μmol per L) or greater; treatment was recommended at levels of 15 μg per dL (0.73 μmol per L) or greater. Based on these changes, in 1993, the American Academy of Pediatrics (AAP) issued recommendations on screening for elevated blood lead levels and preventing lead poisoning. The AAP has recently updated its recommendations for screening and prevention of elevated blood lead levels.
The well-known toxic effects of lead include cognitive deficits. Specifically, a two- to three-point average loss in IQ has been reported in children with blood lead levels averaging 20 μg per dL (0.97 μmol per L), compared with IQ scores in children whose levels average 10 μg per dL (0.48 μmol per L). Other effects associated with lead exposure include aggression, decreased attention, somatic complaints and antisocial or delinquent behavior. Elevated blood lead levels may also be associated with abnormal balance, poor eye-hand coordination and sleep disturbances, although the data for these associations are less consistent than the data for cognitive deficits.
The physician's role in providing anticipatory guidance to prevent lead exposure cannot be overemphasized. Educating parents about potential sources of lead is essential, as is providing information about proper nutrition and the importance of dietary iron. Removal of environmental lead sources is also important.
Universal screening of all children is recommended if the prevalence of elevated blood lead levels in a community is unknown or if more than 27 percent of the housing in the community was built before 1950. Targeted screening is recommended in areas where the prevalence of elevated lead levels in children is less than 12 percent or where fewer than 27 percent of the houses were built before 1950.
A simple at-risk questionnaire can be useful for determining which children should be screened for elevated blood lead levels (see the accompanying figure). Management of elevated blood lead levels proceeds according to a specific scheme (see the accompanying table). A blood lead level of 10 mg per dL (0.48 mmol per L) or greater requires confirmatory testing, with the urgency of the second test depending on the initial value. Patients with blood lead levels of 70 mg per dL (3.38 mmol per L) or higher must be hospitalized immediately.
The recommendations include the following strategies: anticipatory guidance should be provided to parents of infants and toddlers; children at risk should be screened for the first time at nine to 12 months of age and again at about 24 months of age; the possibility of lead exposure history should be assessed periodically, beginning at age six months and continuing until six years of age. The recommendations state that further research is needed to identify which strategies are best for treating elevated lead levels and educating the public about the risks of lead toxicity.