When Plumbism Becomes Painful, Pyretic and Pruritic: A Case Describing Rare Adverse Effects During Chelation and the Utility of N-acetylcysteine

Document Type

Conference Proceeding

Publication Date

2-26-2025

Publication Title

J Med Toxicol

Keywords

acetylcysteine, edetate calcium disodium, hydroxyapatite, protoporphyrin zinc, succimer, adverse drug reaction, aged, case report, chelation, chill, clinical article, conference abstract, diagnosis, drug combination, drug therapy, drug withdrawal, dysphagia, edema, erythema, fever, Helicobacter infection, human, iron deficiency anemia, lead blood level, lead poisoning, male, mouth ulcer, myalgia, nausea, nephrotoxicity, oral drug administration, outpatient department, pruritus, rash, side effect, subcutaneous tissue, superficial thrombophlebitis, upper limb

Abstract

Background: The chelating agents succimer (DMSA) and calcium disodium edetate ( CaNa2EDTA) are typically well tolerated. We present a unique case of a patient who developed an intolerance to both DMSA and CaNa2EDTA during a single course of chelation, necessitating an alternative therapeutic approach. Methods: This is a single case report. Results: A 17-year-old male was admitted with an asymptomatic blood lead level (BLL) of 66.1 mcg/dL. The patient had a history of pica and had presented eight months earlier with a BLL of 79.8 mcg/dL, for which he completed three courses of chelation with DMSA and/or CaNa2EDTA. He was diagnosed with iron deficiency anemia and was treated for a Helicobacter pylori infection. On this admission, his labs showed an elevated zinc protoporphyrin/heme ratio (>600). For his fifth course of chelation, medical toxicology recommended oral DMSA (500 mg) in combination with intravenous CaNa2EDTA (1.55 mg/kg/hr). One hour after his initial dose of DMSA, he developed diffuse pruritus, followed by nausea and dysphagia. His exam revealed small oral ulcerations and a macular rash on his anterior neck, chest, and arms. DMSA was discontinued and all lesions resolved over the following two days. On hospital day (HD) three, the patient developed progressive pain and confluent erythema at the right antecubital IV site, followed by fever (38.5°C), chills, myalgias, and nausea. CaNa2EDTA was discontinued and replaced with an N-acetylcysteine (NAC) infusion. Upper extremity ultrasound revealed confluent hyperechoic thickening, subcutaneous edema, and superficial venous thrombosis. By HD five, bloodwork showed an 18% reduction in the BLL (52.9 mcg/dL), and the patient was discharged. Conclusion: Clinically significant adverse effects are uncommon during lead chelation. Succimer is infrequently associated with severe mucocutaneous eruptions of an unclear etiology, which typically resolve upon discontinuation of the drug. Known toxicities of CaNa2EDTA include nephrotoxicity, febrile systemic reactions, and localized cutaneous hydroxyapatite deposition. Alternate etiologies of iron deficiency anemia should be simultaneously considered. When both standard chelators are intolerable, NAC serves as a reasonable alternative, with clinical evidence supporting its ability to enhance urinary lead elimination.

Volume

21

Issue

2

First Page

125

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