Lead poisoning without encephalopathy. Effect of early diagnosis on neurologic and psychologic salvage.

Medical and psychological status of 166 patients previously treated for lead poisoning and of 22 sibling controls were evaluated. Maximum blood lead levels ranged from 40 to 471 microgram/dL. Eighteen patients had definite symptoms, 32 had questionable symptoms, and 116 were asymptomatic. No patients developed seizures, other neurological sequelae, or abnormal nerve conduction velocity. No statistically significant relationship was found between blood lead concentration (PbB) and subsequent intellectual function. The mean IQ of the patient cohort was 87, approximately at the 50th percentile for inner-city schoolchildren in Chicago. Detection prior to encephalopathy and prompt detoxification were effective in preventing or minimizing sequelae despite high PbBs.