Lead toxicity

Last reviewed: June 2019

Last updated: January 2018

Summary

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 neurodevelopment 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 if blood levels exceed 2.1 micromoles/L (44 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, and all patients therefore require long-term monitoring.

Definition

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, but levels >0.4 micromoles/L (>9 micrograms/dL) in a child or >1.2 micromoles/L (>24 micrograms/dL) in an adult are currently considered to require active interventions. Toxicity occurs at lower levels, but prevention is the approach to preventing such toxicity in the absence of effective management options at such levels.

History and exam

Key diagnostic factors

presence of risk factors
FHx 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
seizures
coma

Full details

Other diagnostic factors

colicky abdominal pain (adults)
hypertension (adults)

Full details

Risk factors

age 9 to 36 months
housing with lead hazards
occupational lead exposure
lead-contaminated water supplies
low socioeconomic status
hobbies working with lead
pica
use of folk medications
fetal exposure
mineral-deficient and high-fat diets
hand-to-mouth activity with toys and other objects
working in bullet firing ranges

Full details

Diagnostic investigations

1st investigations to order

whole-blood lead level
FBC
serum ferritin

Full details

Investigations to consider

24-hour urine lead with chelation
abdominal radiographs
nerve conduction studies

Full details

Emerging tests

x-ray fluorescence of long bones
MRI brain

Full details

Treatment algorithm

ACUTE

all patients

Contributors

Authors VIEW ALL 

J. Routt Reigart, MD

Professor Emeritus of Pediatrics

Medical University of South Carolina

Charleston

Disclosures

JRR declares that he has no competing interests.

Peer reviewers VIEW ALL 

Howard Hu, MD, MPH, ScD

NSF International Chair

Department of Environmental Health Sciences

Professor of Environmental Health Sciences, Epidemiology and Internal Medicine

University of Michigan Schools of Public Health and Medicine

Ann Arbor

Disclosures

HH is an author of a reference cited in this monograph. HH has received research funding greater than 6 figures USD.

Rose H. Goldman, MD, MPH

Chief

Occupational & Environmental Medicine

Cambridge Health Alliance

Associate Professor of Medicine

Harvard Medical School

Associate Professor of Environmental Health Sciences

Harvard School of Public Health

Boston

Disclosures

None disclosed.

Alison Jones, MD, FRCPE, FiBIOL, FRCP, FRACP

Dean

School of Medicine

Campbelltown Campus

University of Western Sydney

Australia

Disclosures

AJ declares that she has no competing interests.

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Lead toxicity

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

1st investigations to order

Investigations to consider

Emerging tests

Treatment algorithm

all patients

Contributors

Authors VIEW ALL 

J. Routt Reigart, MD

Disclosures

Peer reviewers VIEW ALL 

Howard Hu, MD, MPH, ScD

Disclosures

Rose H. Goldman, MD, MPH

Disclosures

Alison Jones, MD, FRCPE, FiBIOL, FRCP, FRACP

Disclosures

Differentials

Guidelines

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