Laura Plencner, MD |Pediatric Hospital Medicine, Children's Mercy | Clinical Assistant Professor of Pediatrics, UMKC
A 3-year-old boy presents with abnormal labs found at a well-child exam. Parents report no concerns with his health except for a speech delay. Review of systems is negative for any complaints. He has previously been growing well, with a body mass index at the 70th percentile. As a result of his lab findings, a radiograph is obtained.
Of the following, what is the most likely exposure that lead to this condition?
D. Water fountain
The correct answer is C.
The radiograph shows increased density of the metaphysis of the tibia and fibula, called “lead lines” and is consistent with lead toxicity. The child’s initial blood lead level was 58 micrograms/deciliter (mcg/dl). The most common source of lead toxicity in children is lead paint. Water and cosmetics are also sources of lead exposure in childhood, although they are less common. Leaded gasoline is an uncommon source of lead in the United States due to the sale being banned in 1995.1,2
Lead is found throughout the environment including in the soil, water and air. However, human toxicity is related to the use of fossil fuels, industry and lead paint. Lead paint was used prior to 1978 and remains a common source of lead exposure when overlying paint peels and flakes onto window sills or the floor and then are ingested. Lead can enter drinking water through corroded pipes and has also been found in cosmetics, folk remedies (azarcon and greta), candy imported from Mexico, and toys made outside of the United States.3
Children exposed to lead can develop behavioral problems, decreased academic achievement, hyperactivity, impaired growth and anemia; thus, prevention of lead poisoning is crucial. Lead screening is performed at well-child exams. A blood lead level (BLL) of 5 mcg/dl is considered elevated, which was recently decreased from 10 mcg/dl based on concerns that even low levels of lead exposure can cause health and developmental effects.2 Although lead toxicity is often asymptomatic, symptoms can include vomiting, abdominal pain, anorexia, lethargy and encephalopathy.4
The environment of any child with detectable lead on screening must be evaluated for a source of lead exposure including lead paint. Abatement should be completed by a lead-safe certified firm. A BLL of 5 mcg/dl or greater is concerning and serial testing is needed, although oral chelation is not recommended. A BLL of greater than 45 mcg/dl requires chelation therapy with oral succimer or with calcium disodium edetate (CaNa2EDTA) or penicillamine, if succimer is contraindicated or not tolerated. Presence of lead in the gastrointestinal tract should be evaluated in children with pica, and bowel irrigation should be completed if lead is present. Hospitalization and treatment with a combination of succimer and CaNa2EDTA is recommended for a blood lead level greater than 70 mcg/dl. BLL may rebound following treatment due to release of lead from bone, which has a half-life of up to 10 years.4
National Center for Environmental Health, Division of Emergency and Environmental Health Services (2018, October 10). Centers for Disease Control and Prevention: Lead. Retrieved from https://www.cdc.gov/nceh/lead/
United States Environmental Protection Agency (2018, December 19). Lead. Retrieved from https://www.epa.gov/lead
National Center for Environmental Health, Division of Emergency and Environmental Health Services (2015, May 29). Centers for Disease Control and Prevention: Sources of Lead. Retrieved from https://www.cdc.gov/nceh/lead/tips/sources.htm
Childhood Lead Poisioning: Management. Lowry J. UpToDate. August 15, 2017, Accessed 23 December 2018.