Rapid Reference

Lead Poisoning

April 6, 2022
Sam Ashoo, MD

Why do we care?

The April, 2022 Peds EMP Article is on the topic of Lead Poisoning in Children. Here are a few alarming facts relevant to our practice in the ED.

  • According to the US Dept of Housing and Urban Development, 29 million homes in the US have significant lead-based paint hazards. 3.3 million of them have children under age 6.
  • It is estimated that 500,000 children in the US have blood levels above the 3.5 ug/dl cut off, which was lowered from 5 ug/dl by the CDC in Oct 2021. (Associated Press)
  • Despite improvements in population lead levels in the US, children of low-income families remain at higher risk and access to resources for treatment are limited. A recent article in the New York Times summarized the challenges experienced by families of children with lead poisoning- How 2 Industries Stymied Justice for Young Lead Paint Victims, By Ellen Gabler, March 29, 2022

Why are children at increased risk?

  • Smaller size and proportionally larger dose of ingested lead
  • Proximity to dirt and dust on the ground
  • Oral exploratory and pica behaviors
  • Their proportionally larger daily water and milk intake
  • Their higher rate of gastrointestinal absorption
  • An immature blood-brain barrier
  • In-utero exposure, since lead readily crosses the placenta

Additionally two populations of children are at significantly higher risk:

  • Children with Autism Spectrum Disorder (ASD)
    • May have persistent pica behaviors
    • May be iron deficient due to restricted diets, leading to increased lead absorption
    • May have symptoms masked by similarity to ASD characteristics
  • Children with Sickle Cell Disease
    • have an unusually high prevalence of pica behavior at all ages
    • have an older age of presentation, 7 compared to 3-4 for children without sickle cell disease
    • have increased risk of deficiencies in calcium, phosphorus, iron, and zinc, leading to increased lead absorption
    • have delayed diagnosis because of similar symptoms to vaso-occlusive pain crises, like abdominal pain and limb pain

Common Sources of Lead Exposure

Source of Lead Exposure

Examples / Comments

Lead-laden dust

Dust from:

  • Peeled or cracked paint

  • Home renovations

Paint chips

  • Older layers of paint that were applied prior to 1978List Item 1

Soil

  • Mining and smelting communities

  • Urban soil from leaded paint and gasoline (leaded gasoline use deposited 4-5 million tons of lead into soil)

Water

  • Leached from corroded pipes

Air

Released from:

  • Factory and smelter emissions

  • Combustion of leaded gasoline

  • Deterioration of lead-based paint 

  • Other industrial sources

Food

  • Grown in contaminated soil

  • Imported spices

  • Stored in ceramic dishware

  • Imported candies from Mexico (especially in chili powder and tamarind)

Nutritional supplements

  • Lead in soil absorbed by the plants used to make supplements

Alternative medicines

  • Greta and azarcon: Mexican remedy to treat upset stomach, diarrhea, vomiting, and teething; fine orange powders with as much as 90% lead content

  • Ba-baw-san: Chinese herbal remedy, treats colic pain and pacifies young children

  • Ghasard: Indian health tonic; brown powder

  • Daw Tway: folk remedy from Thailand and Myanmar used to aid digestion

  • Ayurvedic medicines from India

  • Others: litargio, alkohl, bali bali, coral,liga, pay-loo-ah, reuda

Ceramic dishware

  • Leaded glaze or paint

Cosmetics

  • Sindoor: red powder used by married Indian women

  • Surma: eye makeup used in India

Occupational or hobby exposure of parent

  • Battery manufacturing

  • Recycling plants

  • Demolition/renovation

  • Rubber and plastic industries

  • Ammunition manufacturing

  • Automotive/radiator repair

  • Lead soldering (eg, electronic manufacturing)

  • Welding

  • Painting

  • Plumbing

Children’s toys, jewelry, furniture

  • In 2008, lead >100 ppm was banned from children’s products by the federal government (however, toys with high levels of lead still exist15)

Summary of Children's Health Effects by Blood Level

Blood Level

Health Effects Based on Children

5-10 mcg/dL

Nervous System Effects

  • Cognitive function: Decreases in IQ,  academic achievement, specific cognitive measures

  • Externalizing behaviors: Increased incidence of attention-related and problem behaviors 

  • Auditory function: decreased hearing 

Reproductive and Developmental Effects

  • Reduced postnatal growth

  • Delayed puberty for girls and boys

10-40 mcg/dL

Nervous System Effects

  • Nerve function: slower nerve conduction

Blood Effects

  • Decreased hemoglobin, anemia

40-80 mcg/dL

Gastrointestinal Effects

  •  Abdominal pain, constipation, colic, anorexia and vomiting

Above 80 mcg/dL

Nervous System Effects

  • Severe neural effects: convulsions, coma, loss of voluntary muscle control and death

Additional symptoms not listed above:

  • Renal effects include proximal tubular dysfunction at BLLs as low as 10 mcg/dL, irreversible interstitial nephritis, and interference in vitamin D metabolism.
  • Hypertension

When to consider testing

  • Unexplained gastrointestinal symptoms, such as constipation, abdominal pain (which is usually severe and episodic), vomiting, anorexia, weight loss
  • Persistent unexplained neurologic symptoms such as headaches, confusion, fatigue, somnolence, inability to concentrate, irritability, or hyperactivity
  • Anemia or hypertension of unknown etiology
  • Irritability, aggressiveness, agitation, lack of focus and attention, clumsiness, decreased activity, or somnolence. Ask about the onset and duration of each symptom. Symptoms can rapidly progress to a state of stupor or seizures.

A blood lead level is the test of choice. Testing of tissues (hair) or urine is not a substitute for blood levels and can not be used to guide therapy.

Indications for Chelation Therapy

A blood lead level (BLL) > 45 mcg/dl is typically when chelation therapy is initiated. Chelation therapy has been reported for BLL between 20-44 mcg/dL, however there is no published evidence of benefit. Unfortunately, there is also no published evidence of neurocognitive improvement even with treatment of BLL > 45 mcg/dl. It is highly recommended that local toxicologists or environmental specialists assist in making this decision. They can be found through the regional Pediatric Environmental Health Specialty Unit (PEHSU) or the US Poison Control Centers (1-800-222-1222). Four chelation agents are currently available for treatment:

  1. Succimer
  2. Calcium disodium edetate (CaNa2EDTA)
  3. D-penicillamine
  4. Dimercaprol/British Anti-Lewisite (BAL).

Further Reading

Lead Poisoning in Children: Emergency Department Recognition and Management (Pharmacology CME) Date Release: Apr 2022 This issue reviews lead poisoning in pediatric patients, including key signs and symptoms, management in the emergency department, and formulation of a safe discharge plan.

References

  • Nadler A. Lead poisoning in children: emergency department recognition and management. Pediatr Emerg Med Pract. 2022 Apr;19(4):1-20. Epub 2022 Apr 2. PubMed

Last Updated on January 25, 2023

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