Description

• Results from a high body burden of lead (Pb)—an element with no known physiologic purpose
• Synonym(s): Pb poisoning, inorganic

Epidemiology

• Predominant age: 1 to 5 years, adult workers
• Predominant sex: male > female (1:1 in childhood)

Prevalence

• Half of U.S. children have detectable blood Pb levels, and 1.9% have blood Pb levels >5 μg/dL.
• Centers for Disease Control and Prevention (CDC) estimates 2.5% of U.S. children aged 1 to 5 years have blood Pb levels ≥3.5 μg/dL (new blood Pb reference level). Lead levels are highest in children with public health insurance, residing in pre-1950s housing, or poverty.

Etiology and Pathophysiology

• Inhalation of Pb dust or fumes or ingestion of Pb
• Pb replaces calcium in bones. Pb interferes with heme synthesis, causes interstitial nephritis, and interferes with neurotransmitters, especially glutamine. High Pb levels can lead to encephalopathy, seizures, and coma.
• Pb crosses blood–brain barrier by displacing calcium ions. Pb exposure early in life causes methylation changes leading to epigenetic alterations that may predispose to brain dysfunction.

Risk Factors

• Children with pica or with iron-deficiency anemia
• Residence in or frequent visitation to deteriorating pre-1978 housing with Pb-painted surfaces or recent renovation
• Soil/dust exposure near older homes, Pb industries, or urban roads
• Sibling or playmate with current or past Pb poisoning
• Dust from clothing of Pb worker or hobbyist
• Pb dissolved in water from Pb or Pb-soldered plumbing (e.g., Flint, Michigan 2014 to 2015)
• Pb-glazed ceramics leachate (especially with acidic food or drink)
• Folk remedies, spices, and cosmetics
  • Latin America: azarcon, greta, litargirio (a topical agent)
  • Asia and Middle East: chuifong tokuwan, pay-loo-ah, ghasard, bali goli, kandu, ayurvedic herbal medicine from South Asia, kohl (alkohl, ceruse), surma, saoott, cebagin
• Hobbies: target shooting, glazed pottery making, Pb soldering, preparing Pb shot or fishing sinkers, stained-glass making, car/boat repair, home remodeling
• Occupational exposure: plumbers, pipe fitters, Pb miners, auto repairers, glass manufacturers, ship builders, printer operators, plastic manufacturers, Pb smelters and refiners, steel welders or cutters, construction workers, rubber product manufacturers, battery manufacturers, bridge reconstruction workers, firing range workers, military and law enforcement
• Dietary: zinc or calcium deficiency
• Imported toys or jewelry with Pb
• Retained bullet fragments, especially if multiple fragments, associated with fracture, or in joints

Pediatric Considerations

• Children are at increased risk because of incomplete development of the blood–brain barrier prior to 3 years of age (allowing more Pb into the CNS).
• Ingested Pb 40% bioavailable in children (10% in adults)
• Common childhood behaviors such as frequent hand-to-mouth activity and pica (repeated ingestion of nonfood products) increase the risk of Pb ingestion.

Pregnancy Considerations
Cross-sectional studies suggest an association between elevated blood Pb and preeclampsia.

General Prevention

• Counsel families on sources of Pb and how to decrease exposure.
• Screen high-risk children.
• Warn parents about unsafe home renovations.
• Wet mopping and dusting with a high-phosphate solution (e.g., powdered automatic dishwasher detergent with 1/4 cup per gallon of water) helps control Pb-bearing dust. High-phosphate detergent is no longer available in some states.
• If tap water is potentially Pb contaminated, use cold water instead of hot water and run for 30 to 60 seconds to flush pipes. Use Pb-free water source if possible (bottled or distilled water).

Commonly Associated Conditions

Iron-deficiency anemia