4 Rapid-Fire Facts on Lead Poisoning in Children

Awareness of the potential risks of lead poisoning is mounting nationally as a result of Flint, Michigan, residents’ exposure to lead-contaminated drinking water.

Particular attention is focused on the short- and long-term effects of lead exposure in children. This population is susceptible to lead toxicity because of several important characteristics that differentiate pediatric and adult exposures.

1. Household Exposure

Approximately 4 million households expose children living among them to high levels of lead.¹ Typically, the source is from paint used in household applications prior to 1978.

As lead paint deteriorates in many American homes, it peels, crumbles, and creates dust that can contaminate many surfaces within the house or soil outside. Gastrointestinal absorption could occur with the hand-to-mouth activity of many children, though inhalation of lead-contaminated paint dust could also occur during summer months or when the paint surface is disrupted (eg, during home repairs or renovations).

2. Physiologically-Based Absorption, Distribution, Metabolism, and Excretion²

The toxicokinetics of lead in children increase exposure, decrease elimination, and pose greater risks for toxicity.

Gastrointestinal absorption ranges from 40% to 50% in children, compared to 10% to 15% in adults. Absorption of inhaled lead can also be approximately 2.7 times higher in children than adults.

Lead is distributed in a 3-compartment model: blood, soft tissue, and bone. In children, a lower proportion of lead is deposited in bone, leaving more lead to affect hematologic sites of toxicity, as well as soft tissue sites.

Children eliminate lead in the urine and bile, which is similar to adults. However, they eliminate much less lead on a daily basis, eliminating only 1% to 4% of daily uptake in children versus 33% in adults.

3. Overlooked Lead Concentration²

Clinical manifestations of lead toxicity usually result from accumulation of the element over a long period of time. Thus, children are at high risk of exposure and may have elevated body lead burdens without symptoms.

Over time, exposure to lead can cause deleterious effects on growth from bone and soft tissue exposure and neurocognitive development from central nervous system penetration. In response to these risks, the US Centers for Disease Control and Prevention (CDC) has updated its action threshold of lead concentration in children to 5 mcg/dL.³ Screening for children at risk for lead exposure is recommended by both the American Academy of Pediatricians and the CDC.⁴

4. Life-Threatening Encephalopathy²

Children diagnosed with lead-related encephalopathy are treated aggressively with combination chelation therapy with edetate calcium disodium and British anti-Lewisite (BAL). Pharmacists should recognized that BAL administration is intramuscular.

The initial BAL dose typically requires 6 divided doses, which are then followed by an infusion of edetate calcium disodium. Establishing institutional guidance documents or protocols can assist pharmacists in ensuring the appropriate dosage and dilution is delivered, since it may be a rare occurrence in some hospitals.

The American College of Medical Toxicology is taking to social media to engage health care professionals at 2 PM Eastern Standard Time on March 4, 2016. Any pharmacist who may encounter a lead exposure would greatly benefit from this access to toxicologists to ask them questions directly.

References

• Centers for Disease Control and Prevention. Lead. http://www.cdc.gov/nceh/lead/. Updated January 29, 2016. Accessed February 26, 2016.
• Calello DP, Henretig FM. Lead. Goldfrank's Toxicologic Emergencies (10^th ed.). New York, NY: McGraw-Hill; 2015.
• Advisory Committee on Childhood Lead Poisoning Prevention of the Centers for Disease Control and Prevention. Guidelines for measuring lead in blood using point of care instrument. http://www.cdc.gov/nceh/lead/ACCLPP/20131024_POCguidelines_final.pdf. Published October 24, 2013. Accessed February 26, 2016.
• American Academy of Pediatrics Committee on Environmental Health. Lead exposure in children: prevention, detection, and management. Pediatrics. 2005 Oct;116(4):1036-1046.