Agency for Toxic Substances and Disease Registry
Case Studies in Environmental Medicine (CSEM) 

Lead Toxicity
How Should Patients Exposed to Lead be Treated and Managed?

Learning Objectives

Upon completion of this section, you will be able to

• identify three steps that should be taken at blood lead levels between 10 and 19 µg/dL
• describe additional steps that should be taken for BLL 20-44 µg/dL, 45-69 µg/dL and 70 µg/dL and above

Introduction

In general, the most important management tool for lead-associated diseases is to remove the source of lead exposure. In addition, lead may cause a variety of other diseases and conditions (see “What Are the Physiologic Effects of Lead section) that should be managed appropriately. Since none of these effects are specific to lead poisoning, treatment of these conditions is not discussed here.

Clinical Management

Table 5 provides treatment guidance for children according to BLL based on CDC recommendations. (CDC 2005) Most of the treatment actions listed in the table are described in the bullets below.

• It is important to determine the sources of lead exposure.
• Health departments often provide environmental investigations for children with elevated blood lead levels. These may include looking for lead hazards in their homes and other places where they spend time. If this is not offered, refer patients to private risk assessors or information on home lead hazards available from health departments or agencies such as the U.S. Department of Housing and Urban Development. Practices vary from state to state. (NCHH 2001)
• Health departments can also help patients by looking for other sources of lead exposure, such as ceramic with leaded glazes, home remedies or imported foods containing lead, and family members’ occupations or hobbies.

Lead education and referrals

• Patients with elevated BLLs and their families should receive education about the potential health effects of lead exposure, important environmental and behavioral interventions to reduce potential for lead exposure, and the importance of good nutrition in reducing the absorption and effects of lead.
• Health departments can often furnish educational materials to health-care providers, and many times have an established program for education and coordination of care (case management). In some cases, physicians may want to refer patients to appropriate social services providers (e.g., for learning assistance if the child is falling behind in school) and even, in more extreme cases, to physicians with experience in treating lead poisoning.

Appropriate clinical referrals can and should also be made for lead's health outcomes based on

• a positive clinical exam.
• and/or positive tests (such as 2nd tier neurobehavioral tests, which may also require a referral for diagnosis) if specialty consultation is needed

Diagnostic testing refers to collecting and analyzing a venous blood sample to confirm a capillary blood screening test, before acting on the result.

• A follow-up test is a venous BLL to monitor the status of a child with an elevated diagnostic BLL, to assure that the elevated BLL is not continuing or rising.
• It may be helpful to compare the patient’s blood lead level over time to analyses of expected rate of declines to help confirm removal from the lead source (Roberts et al. 2002).

Clinical evaluation and management

• Clinical management means that the care should be provided by a health care provider and includes the
  • evaluation
  • family lead education and referrals
  • chelation therapy as appropriate (see below)
  • follow-up testing at appropriate intervals
• The evaluation should include
  • a medical history (focusing on developmental progress in the case of children)
  • environmental history
  • nutritional history
  • evaluation of child’s iron status
  • physical examination, to include complications of lead poisoning
• Aggressive environmental intervention
  • Aggressive environmental intervention refers to investigating potential lead exposure pathways and taking immediate steps to control the actual lead hazards identified.
  • If exposure is severe enough, immediate separation from the source is indicated (such as relocation from housing with lead-based paint).
  • For less severe exposure, for example, if lead paint is a major exposure pathway, immediate interim steps such as damp mopping and covering old paint can be taken before long-term measures (e.g., moving or taking all the lead out of the house) are implemented.
  • Environmental intervention should be coordinated through the state or local health department, which is likely to have the best resources and expertise for coordination or support. It is especially important to connect patients and their families with health departments or housing agencies, which can provide guidance on how to find and fix lead hazards safely. Unsafe repairs can easily make lead hazards worse. These agencies may have resources for funding lead hazard reduction. (see: What Instructions Should Be Given to Patients? section.)
• Chelation therapy
  • Chelating agents are drugs that bind with heavy metals in the bloodstream, causing them to be more rapidly discharged from the body in urine and bile.
  • Chelation therapy can be effective at reducing the total lead body burden (and acute toxicity effects) in individuals with high current BLLs, but it is generally not indicated for individuals with BLLs<45 µg/dL.
  • Chelation therapy is not recommended for those persons with high past exposures to lead and low BLLs who wish to remove lead from their bodies, due to the risk of potential harmful effects of the chelating agents and the remobilized lead.
  • Instead, a calcium-rich diet or supplements might be recommended, to prevent calcium deficiency and subsequent release of lead from the bones.
  • Chelation therapy should always be accompanied by aggressive environmental intervention, and the patient should not be returned to the same environmental exposure situation without a correction (e.g. interdiction, remediation) having taken place.
  • The four chelating agents commonly used in treating patients with high BLLs or signs of encephalopathy are shown in the table below.
  • Na₂EDTA (disodium ethylenediaminetetraacetic acid or edetate disodium) should not be used to chelate children because it can cause fatal hypocalcemia (Brown et al. 2006)

Because there are potential side effects associated with each drug, and because treatment protocol differ for each, it is vital that physicians with experience in chelation therapy be consulted before any chelation therapy is begun (AAP 1995).

An accredited regional poison control center, a university medical center, or a state or local health department can help identify an experienced physician. Note also that the CaNa₂EDTA (edetate disodium calcium) mobilization (challenge) test is no longer recommended because of its difficulty, expense, and potential for increasing lead toxicity (AAP 1995).

• Provide lead education and referrals
• Provide diagnostic testing within 3 months and follow-up testing within two to three months
• Proceed according to guidelines in 20-44 range if BLLs persist in 15-19 range
• (The presence of a large proportion of children in the 10-14 µg/dL range should trigger community-wide lead poisoning prevention.)

• Provide lead education and referrals
• Provide coordination of care (case management)
• Perform clinical evaluation and management
• Provide diagnostic testing (from within one month to within one week) and follow-up testing (every one to two months)
• Perform aggressive environmental intervention

• Provide lead education and referrals
• Provide coordination of care (case management) within 48 hrs
• Perform clinical evaluation and management within 48 hrs
• Provide diagnostic testing within 24-48 hours and follow-up testing (in accordance with chelation therapy, at least once a month)
• Perform aggressive environmental intervention
• Provide appropriate chelation therapy

• This is a medical emergency.
• Perform diagnostic testing immediately as an emergency lab test
• Hospitalize and begin immediate chelation therapy
• Begin other activities as above

Calcium disodium versenate

Edetate disodium calcium

Calcium disodium ethylenediaminetetracetate

CaNa₂EDTA

BAL in oil
(British antilewisite)

Dimercaprol

2,3-dimercapto-propanol

BAL

Cuprimine

D-penicillamine

3-mercapto-D-valine

D-penicillamine

Chemet

Succimer

Meso-2,3-dimercaptosuccinic acid

DMSA

Key Points

• There is a continuum of options—including education, aggressive environmental intervention, and, for more extreme cases, chelation therapy—available to treat patients with elevated BLLs (≥10 µg/dL). Selection of treatment options depends largely on a patient’s BLL and physical exam.
• For the majority of lead-exposed patients, some combination of lead education, aggressive environmental intervention, clinical management, and continued monitoring is indicated. Chelation therapy is only indicated in patients with extremely high or high and persistent BLLs.
• All elevated BLL tests should be reported to the local or state health department as required in the particular state and the HCP should coordinate with the health department in case management as well.

Progress Check