Lead Poisoning



  • Lead has multiple mechanisms of toxicity:
    • Binds sulfhydryl groups and affects multiple enzymatic processes
    • Resembles Ca2+ thereby interfering with Ca2+-dependent processes, such as cell signaling
    • May have mutagenic potential and play a role in human carcinogenesis
  • Distribution:
    • Up to 99% of lead is bound to erythrocytes after initial absorption
    • Ultimately redistributed into bone:
      • 95% of total body lead in adults
      • 70% of total body lead in children
    • High lead levels in the serum compromise the blood–brain barrier and result in lead entry into the CNS and neurotoxicity
  • Often coexists with iron deficiency; this allows for increased lead absorption in the gut
  • Impairs heme synthesis, leading to elevated free erythrocyte protoporphyrin (FEP); these complex with zinc, resulting in elevated zinc protoporphyrin (ZPP)
  • Levels correlate poorly with symptoms:
    • Associated with drops in intelligence quotient (IQ) and increase in violent behavior


  • Acute toxicity:
    • Most often due to inhalation of an environmental source or ingestion of substance containing lead
      • Pottery glaze
      • Certain folk remedies
      • Cosmetics
      • Jewelry
      • Weights
      • Home-distilled alcoholic beverages
      • Lead dust from ammunition and primer
  • Chronic toxicity:
    • Occupational exposures (usually via inhalation):
      • Battery manufacturing/recycling
      • Bridge painting
      • Construction workers
      • De-leading
      • Electronic waste recycling
      • Firing range instructors
      • Mining and smelting
      • Pottery workers
      • Welders
    • Home exposures (pediatric poisoning):
      • Lead-based paint inhalation/ingestion from toys and walls
      • Contaminated water from old pipes
      • Lead dust from the clothing of a parent exposed at work
      • Imported foods
      • Folk medicines

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