A 1-year-old boy is brought to the office for a routine visit. The patient recently transitioned from breast milk to whole milk and enjoys various table foods, including fruits, vegetables, and grains. The family is vegetarian and adds protein to his diet through beans and nut butters. He says 2 words, recently started walking, and often chews on his toys and books. The family lives in a house built in the 1940s that has no chipping paint and has recently been renovated, except for the basement and bedrooms. Height, weight, and head circumference are at the 50th percentile for age. Physical examination is normal. Capillary blood test results are as follows:
| Hemoglobin | 12.5 g/dL |
| Lead | 12 µg/dL (normal <5 µg/dL) |
Which of the following is the most appropriate next step in management of this patient?
Lead poisoning | |
Risk |
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Clinical |
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Management |
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Children are typically exposed to lead through inhalation or ingestion of lead particles from their environment. They are at increased risk of lead poisoning compared with adults due to an incomplete blood-brain barrier, increased mouthing of objects in their environment, and increased gastrointestinal absorption of lead. A risk factor for elevated lead levels is living in a home built before 1978, especially if there is peeling paint or dust released during renovation. Other risk factors include lead piping, having a parent who works with batteries or pottery, or having a playmate or sibling with a history of lead poisoning.
Patients who are symptomatic from lead toxicity can have anemia, abdominal pain, and encephalopathy. Targeted screening of high-risk populations regardless of symptoms is important as most children with lead toxicity are initially asymptomatic but can have cognitive and behavioral problems that become apparent after school entry.
Capillary (fingerstick) blood specimens are widely used in screening for lead poisoning, but false-positive results are common due to environmental contamination and improper collection. Confirmatory venous lead measurement is required to confirm the diagnosis of elevated lead level if a screening capillary lead level is ≥5 µg/dL.
(Choice A) Wallpapering over walls painted with lead-based paint is not an appropriate treatment measure, as the paint can still loosen underneath the paper and release lead dust. Lead paint should be encapsulated or removed by a professional to avoid exposure.
(Choices B, C, and D) This patient does not meet the threshold for chelation therapy. Although he is still at risk of cognitive impairment, chelation therapy is not routinely administered for lead levels <45 µg/dL due to lack of evidence for improved neurologic outcomes compared with removal from the lead-containing environment. Dimercaptosuccinic acid (succimer) is typically used when lead levels are 45-69 µg/dL. Dimercaprol (British anti-Lewisite) plus calcium disodium edetate (EDTA) should be administered on an emergency basis for levels ≥70 µg/dL or acute encephalopathy.
(Choice F) Abdominal x-rays can detect radiopaque lead flecks, paint chips, or lead-paint–covered foreign bodies. Imaging is indicated for patients with elevated levels and gastrointestinal symptoms (constipation, abdominal pain, vomiting) or suspicion of foreign body ingestion.
(Choice G) Patients with elevated blood lead levels should be screened for iron deficiency and prescribed oral ferrous sulfate if deficiency exists. Comorbid iron deficiency can increase gastrointestinal absorption of lead.
Educational objective:
Targeted screening for elevated blood lead levels should be performed in children with risk factors (eg, home built before 1978). Due to the potential of falsely elevated results with capillary testing, repeat testing by venous blood draw should be performed to verify a high blood lead level.