Lead toxicity occurs after occupational or home exposure to lead. There is no threshold level for toxicity.
Anyone at risk of lead exposure requires screening with regular blood lead measurements. There is no 'normal' level, and interventions are initiated at the first sign of increased exposure.
Causes neurodevelopmental dysfunction in children and a range of cardiovascular, renal, neurological, and haematological dysfunctions in adults.
The mainstay of treatment is removal of the source. Chelation therapy is given for blood levels ≥2.2 micromoles/L (≥45 micrograms/dL) in a child or >3.4 micromoles/L (>70 micrograms/dL) in an adult, or if the patient is symptomatic.
Acute lead encephalopathy is a medical emergency requiring aggressive chelation therapy in an intensive care setting.
Acute symptoms resolve with treatment, but neurological impairments and cardiovascular toxicities are irreversible.
Lead resides in bone for decades after exposure has ceased; all patients require long-term monitoring.
Lead toxicity is a multisystem disease produced by inhalation or ingestion of lead. It produces neurodevelopmental dysfunction in children and a range of cardiovascular, renal, neurological, and haematological dysfunctions in adults. Any detectable lead level is consistent with exposure to lead.
The US Centers for Disease Control and Prevention (CDC) employs a blood lead reference value of ≥0.17 micromoles/L (3.5 micrograms/dL) to identify children with blood lead levels greater than most other children’s levels. A case definition for an elevated blood lead level in an adult (person ≥16 years of age) is ≥0.24 micromoles/L (5 micrograms/dL). In an adult, the US Occupational Safety and Health Administration considers a blood lead level of ≥1.2 micromoles/L (25 micrograms/dL) to be serious, requiring inspection.
History and exam
Key diagnostic factors
- presence of risk factors
- family history of lead poisoning or parental work with lead
- cognitive impairment (children)
- behavioural changes (children)
- headaches (children)
- clumsiness and agitation (children)
- loss of appetite (children)
- constipation (children)
- somnolence (children)
- altered mental state
- cerebellar signs
Other diagnostic factors
- colicky abdominal pain (adults)
- hypertension (adults)
- age 9 to 36 months
- housing with lead hazards
- occupational lead exposure
- lead-contaminated water supplies
- low socioeconomic status
- hobbies working with lead
- use of folk medications
- fetal exposure
- mineral-deficient and high-fat diets
- bullet firing ranges
1st investigations to order
- whole-blood lead level
- full blood count
- serum ferritin
Investigations to consider
- 24-hour urine lead with chelation
- abdominal radiographs
- nerve conduction studies
- x-ray fluorescence of long bones
- MRI brain
- Iron deficiency anaemia
- Non-lead peripheral neuropathy
- Arsenic poisoning
- WHO guideline for clinical management of exposure to lead
- Childhood lead poisoning prevention
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