lead poisoning

Last edited 04/2022 and last reviewed 05/2022

Poisoning due to absorption or ingestion of lead affects the brain, the nervous and digestive system and blood (1,2).

Lead poisoning is associated with Raynaud's phenomenon. It is also a possible cause of dementia and epilepsy

• lead poisoning is believed to be primarily responsible for the collapse of the Roman Empire, in which lead acetate was used as a sweetener of wine (2)
  • its prolonged use was considered to have caused dementia to many Roman emperor

As of 2012, the Centers for Disease Control and Prevention (USA) have set the standard elevated blood lead level for adults to be 10 µg/dL and for children 5 µg/dL of the whole blood

The appearance of clinical manifestations varies from individual to individual depending on other environmental factors (2)

• in some there is a clear appearance of clinical features even at lower levels, while some are asymptomatic even at higher levels of lead present in their body fluids
• children are more prone to the effects of lead because usually their organs are in a developing stage
  • symptoms of toxicity may develop acutely with substantial exposure, or insidiously with lower exposures as lead accumulates in the body
    • sequelae may persist into adolescence and adulthood
  • thus blood lead levels have to be set lower and must be frequently checked, particularly where contamination is expected

• children with pica (compulsive ingestion of non-food items), especially ingesting soil or paint

• hand-to-mouth behaviour (eg, age appropriate behaviour in crawling or preschool age children)

• migrants from countries with high use of lead

• degraded or recently renovated older housing, residence close to lead environmental hazards

• nutritional status (insufficient dietary calcium, and deficiencies in iron and potentially zinc)
  
  
• human exposure to lead and its compounds occurs mostly in lead related occupations with various sources like leaded gasoline, industrial processes such as smelting of lead and its combustion, pottery, boat building, lead based painting, lead containing pipes, battery recycling, grids, arm industry, pigments, printing of books, etc

Key points with respect to lead poisoing in children (1):

• lead is a persistent environmental contaminant that can cause toxicity even at low blood lead concentrations (BLC)

• young children and fetuses are most at risk of neurological damage, which may persist into adolescence and adulthood

• identifying and removing the exposure source are the mainstays of management in children with elevated BLC (>=0.1 µmol/L (>=2 µg/dL)).

• notify local public health teams about children with BLC denoting unusually high lead exposure (defined as >=0.24 µmol/L (>=5 µg/dL)) for investigation and management

• chelation may be indicated in children who are symptomatic, or with very high BLC (>=2.4 µmol/L (>=50 µg/dL))

Reference:

• Roberts D J, Bradberry S M, Butcher F, Busby A. Lead exposure in children BMJ 2022; 377 :e063950 doi:10.1136/bmj-2020-063950
• Wani AL, Ara A, Usmani JA. Lead toxicity: a review. Interdiscip Toxicol. 2015;8(2):55-64. doi:10.1515/intox-2015-0009