injuries poisoning
Lead Poisoning
Treatment of Lead Poisoning
Source of lead eliminated (eg, whole-bowel irrigation if lead in gastrointestinal tract) Chelation for adults with symptoms of poisoning plus whole blood lead level (PbB)>70 mcg/dL (>3.38 micromol/L) Chelation for children with encephalopathy or PbB>45 mcg/dL (>2.17 micromol/L) For all patients, the source of lead is eliminated. If lead chips are visible on abdominal x-ray, Whole-bowel irrigation with a Chelating drugs (eg,succimer[meso-2,3-dimercaptosuccinic acid], CaNa2EDTA [calcium disodium ethylenediaminetetraacetic acid]dimercaprol[British antilewisite, or BAL]) can be given to bind lead into forms that can be excreted. Chelation should be supervised by an experienced toxicologist. Chelation is indicated for adults with symptoms of poisoning plus PbB>70 mcg/dL (3.38 micromol/L) and for children with encephalopathy or PbB>45 mcg/dL (>2.17 micromol/L). Liver and kidney disorders are relative contraindications for chelating drugs. Chelating drugs should not be given to any patient with ongoing exposure to lead because chelation can increase gastrointestinal absorption of lead. Chelation removes only relatively small amounts of metal. If total body burden of lead is very large, multiple chelations over many years may be required. Patients with encephalopathy are treated withdimercaprol75 mg/m2(or 4 mg/kg) IM every 4 hours and CaNa2EDTA [calcium disodium versenate] 1000 to 1500 mg/m2IV (infusion) once/day. The first dose ofdimercaprolshould precede the first dose of CaNa2EDTA by at least 4 hours to prevent redistribution of lead into the brain.Dimercaprolmay be stopped after the first few doses depending on lead levels and symptom severity.Dimercaprol-CaNa2EDTA combination therapy is given for 5 days, followed by a 3-day washout period; then the need for continued chelation is reassessed. Patients without encephalopathy are usually treated withsuccimer10 mg/kg orally every 8 hours for 5 days, followed by 10 mg/kg orally every 12 hours for 14 days. If these patients have symptoms, they can alternatively be treated for 5 days withdimercaprol50 mg/m2via deep IM injection every 4 hours plus CaNa2EDTA 1000 mg/m2IV once/day. can also cause pain at the injection site, numerous systemic symptoms, and, in patients with Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency , moderate to severe acute intravascular hemolysis. This drug should not be given concurrently with iron supplements. CaNa2EDTA (calcium disodium versenate) can cause thrombophlebitis, which can be prevented by giving the drug IM, not IV, and by using an IV concentration of<0.5%. Before beginning treatment with CaNa2EDTA, adequate urine flow must be confirmed. Serious reactions to CaNa2EDTA include renal insufficiency, proteinuria, microscopic hematuria, fever, and diarrhea. Renal toxicity, which is dose-related, is usually reversible. Adverse effects of CaNa2EDTA are probably due to zinc depletion. Succimermay cause rash, gastrointestinal symptoms (eg, anorexia, nausea, vomiting, diarrhea, metallic taste), and transient elevations of liver enzymes. Patients with PbB>3.5 mcg/dL (0.17 micromol/L) should be monitored closely with retesting as needed, and they or their parents should be taught how to reduce their exposure to lead. 