Lead poisoning

Lead poisoning results from the accumulation of lead in the body, which is toxic to multiple organ systems. Children are particularly susceptible to lead poisoning and may develop lasting neurodevelopmental impairments. Common sources of lead exposure include lead-based paint in older homes and occupational contact. While often asymptomatic, lead poisoning can manifest with cognitive impairment, myalgia, abdominal pain, and, in severe cases, encephalopathy or coma. Elevated venous blood lead levels (BLLs) confirm the diagnosis. Supportive diagnostics include laboratory studies such as a CBC and peripheral blood smear, which may show anemia and basophilic stippling. There is no known safe BLL, and intervention should be initiated as soon as lead is detected. Management focuses on measures to minimize lead exposure and, in severe cases, lead chelation therapy. Prevention through public health measures and screening of at-risk populations is crucial to avoid the irreversible health effects of lead exposure.

Routes of exposure ^[1][2]

• Ingestion (more common in children)
• Inhalation (more common in adults)

Sources of lead exposure ^[1][3][4][5]

• Drinking water (e.g., leached from lead plumbing) ^[5][6]
• Lead-based paint (common source in children), e.g., from:
  • Living in or regularly visiting buildings built before 1978 (especially if paint is damaged or peeling and during renovations)
  • Antique or imported toys
• Food sources ^[1][5]
  • Using lead-containing kitchenware to prepare, store, or consume food (e.g., glazed ceramics, leaded crystal)
  • Lead-containing dyes (e.g., in imported candy)
  • Unregulated or home-distilled spirits (moonshine)
  • Game killed with lead ammunition
• Traditional medicines (e.g., herbal medicine, ayurvedic medicine)
• Cosmetics and jewelry ^[6]
• Direct or secondary occupational exposure (e.g., from battery manufacturing, metallurgy, construction) ^[7][8]
• Contaminated soil (e.g., near roads, older homes, or airports)
• Aircraft emissions (e.g., living near an airport)

• Inhibition of aminolevulinate dehydratase and ferrochelatase → disruption of heme synthesis → ↑ protoporphyrin and ↑ aminolevulinic acid in RBCs ^[3]
• Inhibition of heme synthesis → microcytic, hypochromic, or normochromic anemia ^[1]
• Inhibition of the breakdown of ribosomal RNA → precipitation of ribosomes and ribosomal RNA in the cytoplasm of erythrocytes → basophilic stippling ^[9]

Acute and chronic lead poisoning manifest similarly in both children and adults. ^[1][2][3]

• Mild lead poisoning
  • Fatigue, lethargy
  • Cognitive impairment
  • Irritability
  • Additional findings in children: hearing and growth impairment, delayed puberty
• Moderate lead poisoning
  • Neurological
    • Headache, memory loss, insomnia
    • Peripheral neuropathy (due to demyelination of peripheral nerves)
  • GI: abdominal pain, constipation, metallic taste, anorexia, nausea, vomiting
  • Musculoskeletal: myalgias, arthralgias, gout
• Severe lead poisoning
  • Neurological
    • Encephalopathy, seizures, coma, signs of increased intracranial pressure
    • Peripheral neuropathy, particularly in the radial nerve (causing wrist drop) and the peroneal nerve (causing foot drop)
  • Renal: nephropathy
  • GI: abdominal colic, vomiting

Patients with lead poisoning and poor dental hygiene may develop a purple-blue line on the gums (i.e., Burton line). ^[1]

ABCDEFGH: Anemia, Basophilic stippling, Constipation, Demyelination, Encephalopathy, Foot drop, Gum deposition/Growth restriction/Gout, Hyperuricemia/Hypertension

See also “Diagnostics for the poisoned patient.”

Approach ^[1][2][3]

• Obtain a venous BLL in:
  • Symptomatic individuals with known lead exposure
  • Asymptomatic individuals as part of lead screening ^[10][4]
• Venous BLL ≥ 3.5 mcg/dL is considered elevated.^[4][11]
• Consider additional laboratory studies and imaging to identify:
  • Complications of lead exposure (e.g., anemia, chronic kidney disease) ^[10]
  • Sources of lead exposure (e.g., ingested objects, bullets)

Lead screening ^[4][10][12]

• Indications
  • All adults and children with potential exposure to sources of lead
  • On arrival to the US for: ^[6][13]
    • Refugees who are ≤16 years of age, pregnant, or lactating
    • Children with recent immigration or international adoption
  • Children with any of the following should be screened both at 1 and 2 years of age (or between 2 and 6 years of age if not previously screened):^[4]
    • Medicaid enrollment
    • Residence in a community with a high or unknown risk of lead exposure ^[5]
• Modality ^[4]
  • Capillary or venous BLL ^[14]
  • If BLL is elevated on capillary blood sample testing, repeat the study with a venous blood sample. ^[4][7][14]
• Follow-up of positive lead screen
  • Nonpregnant adults and children: See "Management of lead exposure in asymptomatic individuals."
  • Pregnant and lactating individuals: See "Lead poisoning in pregnant and lactating individuals."

Ancillary laboratory studies

• CBC: microcytic, hypochromic, or normochromic anemia ^[2]
• Peripheral blood smear: basophilic stippling of erythrocytes ^[2]
• BMP
• LFTs
• Urinalysis

Imaging studies

• Abdominal x-ray: Consider for individuals with BLL ≥ 20 mcg/dL to assess for ingested lead-containing objects (e.g., paint chips). ^[4]
• Wrist or knee x-rays: may show dense metaphyseal bands (lead lines)
• X-rays to assess for retained bullets or shrapnel

Avoid performing lumbar punctures in patients with suspected lead encephalopathy because of the risk of cerebral herniation. ^[3]

Approach to lead poisoning ^[1][4]

• Symptomatic individuals with acute exposure
  • Provide initial management of acute lead exposure, including lead chelation therapy.
  • Admit to hospital for ongoing management.
• Asymptomatic individuals with elevated BLL on screening
  • Determine the need for hospitalization and lead chelation therapy based on BLL.
  • See "Management of lead exposure in asymptomatic individuals" for details.

Lead poisoning is a nationally notifiable disease in the US. Notify local public and/or occupational health departments if a case is confirmed.

Lead chelation therapy ^[3]

Use body surface area-based dosing.

Adults

• Encephalopathy and/or BLL > 100 mcg/dL
  • Dimercaprol (off-label)
  • PLUS edetate calcium disodium 4 hours after initiating dimercaprol ^[3]
• Symptomatic and/or BLL 70–100 mcg/dL: succimer (off-label) ^[3]
• Asymptomatic and BLL < 70 mcg/dL: Chelation therapy is usually not indicated.

Children

• Encephalopathy
  • Dimercaprol (off-label)
  • PLUS edetate calcium disodium 4 hours after initiating dimercaprol ^[3]
• Symptomatic and/or BLL ≥ 70 mcg/dL
  • Dimercaprol (off-label)
  • PLUS edetate calcium disodium 4 hours after initiating dimercaprol ^[3]
• Asymptomatic and BLL 45–69 mcg/dL
  • Succimer ^[3]
  • OR edetate calcium disodium
• Asymptomatic and BLL < 45 mcg/dL: Chelation therapy is usually not indicated.

Dimercaprol is no longer manufactured. Consult local poison control or the health department for guidance on alternative treatments (e.g., monotherapy with succimer, use of expired dimercaprol).

Initial management of acute lead poisoning

• Perform the ABCDE approach in poisoning and initiate stabilization as needed.
• Call the local Poison Control Center: In the US, the Poison Help line is 1-800-222-1222.
• Perform GI decontamination.
  • For ingestions of solid lead objects (e.g., bullets, jewelry): ^[1]
    • Pre-pylorus: endoscopic removal
    • Post-pylorus: whole bowel irrigation
  • For ingestions of lead-containing liquid or other substances: whole bowel irrigation ^[1]
• Administer lead chelation therapy based on BLL and/or symptom severity.
• Address environmental exposure (e.g., removal of substance or patient from the environment).

Ongoing management ^[2][3]

• Admit all symptomatic patients to the hospital for further management in consultation with toxicology.
• Manage patients with encephalopathy in the ICU.

All patients

• Evaluate for sources of lead exposure, including an environmental assessment of the patient's home if needed.
• Determine need for lead chelation therapy based on venous BLL; consult a specialist as needed.
• Report lead poisoning to local public and/or occupational health departments.
• Educate on measures to minimize lead exposure.
• Encourage adequate daily intake of iron and calcium; recommend supplementation as indicated. ^[1]

Children ^[2][3]

• Assess for indications for hospitalization.
  • All children with BLL ≥ 69 mcg/dL
  • Consider for children with BLL ≥ 45 mcg/dL unable to immediately minimize lead exposure. ^[4]
• Determine the need for lead chelation therapy based on BLL.
  • BLL ≥ 45 mcg/dL: Start lead chelation therapy.
  • BLL < 45 mcg/dL: Perform monitoring of elevated BLL in children.
    • The frequency of monitoring varies based on initial venous BLL. ^[4][5]
    • Consider more frequent monitoring in summer months as lead exposure may increase. ^[1][4][5]

Adults

• Pregnant and lactating individuals: See "Lead poisoning in pregnant and lactating individuals."
• Nonpregnant individuals with occupational exposure ^[10][15]
  • Perform serial BLL monitoring in all patients with venous BLL ≥ 3.5 mcg/dL. ^[15]
  • Refer to occupational medicine to evaluate for a change of job or work environment if: ^[15][16]
    • Venous BLL ≥ 30 mcg/dL
    • Persistent BLL elevation ≥ 10 mcg/dL despite exposure control measures

The following measures are recommended for both primary prevention of lead poisoning and to minimize further exposure to lead in patients with elevated BLL. ^[4][6]

• For buildings built before 1978: ^[1][5]
  • Consider a lead hazard screen or full risk assessment for lead exposure.
  • Conceal or remove peeling paint.
  • Hire EPA-certified contractors for remodeling or repair work.
  • Wet-wipe contact surfaces.
• For lead-containing water: ^[5]
  • Replace or upgrade plumbing lines installed before 1986 when possible.
  • Use National Sanitation Foundation-certified lead filters until old plumbing is replaced.
  • Consume only cold tap or bottled water.
• For individuals with jobs or hobbies that involve lead exposure: ^[8][14]
  • Eliminate occupational exposure when possible. ^[16]
  • Remove shoes before entering the home.
  • Wash exposed clothes separately.
• Counsel parents or caregivers about other common sources of lead exposure.
• Clean children's toys frequently.
• Wash hands frequently and before each meal.
• Identify and treat iron deficiency; encourage age-appropriate daily intake of iron and calcium. ^[1][4]

Lead poisoning in pregnant and lactating individuals ^[1][7][14]

• Elevated BLL during pregnancy is associated with adverse maternal and childhood outcomes, including:
  • Pregnancy loss
  • Gestational hypertension
  • Fetal growth restriction and low birth weight
  • Impaired neurodevelopment
• Lead screening is recommended:
  • At the first prenatal visit for all individuals with potential exposure to sources of lead ^[7]
  • For recent refugees who are pregnant or lactating ^[13]
• Pregnant and lactating individuals with BLL ≥ 5 mcg/dL require further management. ^[11][12][14]
• Management of elevated BLL should be performed in consultation with a specialist (e.g., maternal-fetal medicine, toxicology) and may include: ^[7][14]
  • Evaluating for sources of lead exposure and educating on measures to minimize lead exposure.
  • Lead chelation therapy, depending on venous BLL
  • Increased calcium and iron intake, with supplementation as necessary ^[7]
  • Monitoring of maternal BLL throughout pregnancy and at delivery
  • Breastfeeding modifications and infant BLL monitoring ^[17]

Maternal BLL ≥ 45 mcg/dL is considered a high-risk pregnancy. Consult or refer to clinicians with experience in managing lead poisoning during pregnancy. ^[7][14]

Individuals should not breastfeed until BLL is < 40 mcg/dL. Individuals with higher BLL who wish to breastfeed should pump and discard breast milk until this level is reached. ^[7][17]