Lead Poisoning

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

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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

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.

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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).

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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.

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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