For lead poisoning, under what circumstance should calcium disodium EDTA therapy be withheld?

For lead poisoning, under what circumstance should calcium disodium EDTA therapy be withheld?

• A. If ALT is elevated
• B. If calcium level is high-normal
• C. If BUN is elevated
• D. If creatinine is elevated indicating renal impairment

Answer: (B)

Calcium disodium EDTA can lower serum calcium because the chelation process can bind calcium as it removes lead from the body. If the calcium level is high-normal, starting EDTA therapy risks driving calcium down into the hypocalcemic range, which can cause symptoms like paresthesias, muscle cramping or tetany, and potentially cardiac conduction problems. To prevent that dangerous drop, withholding the therapy until calcium is safer is the prudent choice. Elevated liver enzymes or a high BUN aren’t direct reasons to withhold this chelation in the same way, and while renal impairment (elevated creatinine) is a concern with EDTA because it’s renally excreted, the immediate, concrete reason given here is the risk of inducing hypocalcemia when calcium is already at the high-normal level.

Calcium disodium EDTA can lower serum calcium because the chelation process can bind calcium as it removes lead from the body. If the calcium level is high-normal, starting EDTA therapy risks driving calcium down into the hypocalcemic range, which can cause symptoms like paresthesias, muscle cramping or tetany, and potentially cardiac conduction problems. To prevent that dangerous drop, withholding the therapy until calcium is safer is the prudent choice.

Elevated liver enzymes or a high BUN aren’t direct reasons to withhold this chelation in the same way, and while renal impairment (elevated creatinine) is a concern with EDTA because it’s renally excreted, the immediate, concrete reason given here is the risk of inducing hypocalcemia when calcium is already at the high-normal level.