From the Guidelines
Chelation therapy is recommended for individuals with blood lead levels exceeding 44 μg/dL (>440 ppb), as indicated by the most recent guidelines. According to the American Academy of Pediatrics 1, children with blood lead concentrations >44 μg/dL (>440 ppb) should be considered for hospitalization or chelation therapy, managed with the assistance of an experienced provider. The decision to initiate chelation therapy should be based on factors such as the safety of the home or child care facility with respect to lead hazards, isolation of the lead source, family social situation, and chronicity of the exposure.
Key considerations for chelation therapy include:
- Confirmation of the blood lead concentration with repeat venous lead level within 48 hours
- Consultation with an expert, such as a pediatric environmental health specialty unit or Poison Control Center
- Identification and removal of the lead exposure source to prevent reaccumulation
- Close medical supervision due to potential side effects, including kidney damage, mineral depletion, and allergic reactions
The primary chelating agents used include succimer (DMSA) for oral administration, calcium disodium EDTA (CaNa2EDTA) for more severe cases, administered intravenously, and dimercaprol (BAL) for very high levels or encephalopathy, given intramuscularly 1. Treatment duration and follow-up monitoring should be individualized based on the patient's response to therapy and the presence of any adverse effects.
From the Research
Lead Level for Chelation Therapy
The lead level that would require chelation therapy is typically considered to be above 45 micrograms/dL in children, as indicated by the study 2. This is because succimer, an oral lead chelator, is designated for the treatment of lead poisoning in children with blood lead concentrations higher than 45 micrograms/dL.
Blood Lead Concentrations and Chelation Therapy
- Blood lead concentrations above 100 mcg/dL can lead to severe symptoms such as lead encephalopathy, as reported in the case study 3.
- Chelation therapy may be necessary for blood lead concentrations above 45 micrograms/dL, with succimer being a commonly used oral chelator 2.
- The Treatment of Lead-Exposed Children Trial (TLC) studied the effect of succimer in treating low levels of lead exposure (20-44 mcg/dL) in children, but found no detectable improvement in cognitive or behavioral function 4.
Comparison of Chelation Therapies
- Sodium calcium edetate and succimer (DMSA) are both effective chelators of lead, but there is currently insufficient data to conclude that either antidote is superior in enhancing lead excretion 5.
- DMSA may be more effective than sodium calcium edetate in reducing kidney lead concentrations, while sodium calcium edetate may be more effective in reducing bone lead concentrations 5.