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Pediatric Lead Toxicity Workup

  • Author: Mohamed K Badawy, MD, FAAP; Chief Editor: Timothy E Corden, MD  more...
 
Updated: Jun 22, 2016
 

Approach Considerations

In the early 1990s, both the Centers for Disease Control and Prevention (CDC) and the American Academy of Pediatrics (AAP) recommended universal screening for lead toxicity in children at 1 and 2 years of age. With the subsequent decline in median blood lead concentrations, those organizations currently recommend performing environmental assessments to identify children at risk for lead exposure before screening.[8, 12]

Perform a rapid bedside glucose determination in children who present with altered mental status. Obtain serum pH and electrolyte levels, including calcium, magnesium, and phosphorus. Check for anion gap acidosis (see the Anion Gap calculator) that may be present in co-ingestions. A complete blood count (CBC) may reveal hypochromic microcytic anemia. Basophilic stippling of the erythrocytes, which is characteristic of lead poisoning, is uncommon in children.

Perform urinalysis. Children may appear mildly dehydrated, with concentrated urine and poor appetite. This can signal the beginning of the development of inappropriate secretion of antidiuretic hormone.

Whole blood lead level

Whole blood lead level (BLL) is the criterion standard for confirming the diagnosis of lead poisoning. For convenience, a fingerstick capillary lead level has been used for screening. Properly collected capillary samples have a 10% false-positive rate. Once an elevated lead level is detected, a venous lead level is assessed for confirmation.

Until recently, a BLL of 10 μg/dL or higher was considered to denote poisoning. Currently, the CDC recommends 5 μg/dL as a threshold for identifying children who have been exposed to lead and prompting measures to reduce the child’s future exposure to lead. That level corresponds to the 97.5th percentile of BLLs in US children aged 1–5 years from two consecutive cycles of the National Health and Nutrition Examination Survey (NHANES), which will be recalculated every 4 years. A BLL of 45 μg/dL remains the threshold for consideration of chelation therapy.[8]

Erythrocyte protoporphyrin

Erythrocyte protoporphyrin (EP) may be obtained in selected patients. Lead toxicity affects heme synthesis at several steps; this includes interference with the enzyme ferrochelatase, leading to the accumulation of EP. EP is easily detected because it fluoresces easily. EP is an adjunct for the diagnosis in the presence of elevated lead levels of 55 mcg and higher. At lead levels below that, EP is not a very sensitive measure, and its positivity declines. Therefore, EP is not used as a primary screening tool.

Hair samples

In Russia, hair sample is the standard for lead poisoning screening. However, studies have demonstrated that blood lead specimens are more sensitive than hair samples in detecting lead exposure.

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Imaging Studies

Abdominal radiography

Presence of radiopaque flakes is a clear indicator of pica.

Long-bone radiography

Radiodensity may be detected at the distal metaphyseal area. These indications, known as lead lines, are true growth arrest lines and, although not pathognomonic, are associated with chronic lead exposure.

Chest radiography

This study is indicated in patients with lead encephalopathy to confirm the position of the endotracheal tube. Although radiographic findings of suspected aspirations may be initially absent, an initial radiograph is often helpful.

CT scanning

Head computed tomography (CT) scanning may be needed in patients who present with altered mental status to exclude cerebral edema and structural lesions.

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Contributor Information and Disclosures
Author

Mohamed K Badawy, MD, FAAP Assistant Professor of Emergency Medicine and Pediatrics, University of Texas Southwestern Medical School; Associate Medical Director, Division of Emergency Medicine, Children's Medical Center Dallas

Mohamed K Badawy, MD, FAAP is a member of the following medical societies: Academic Pediatric Association, Society for Academic Emergency Medicine, American Academy of Pediatrics

Disclosure: Nothing to disclose.

Coauthor(s)

Gregory P Conners, MD, MPH, MBA Director, Division of Emergency and Urgent Care, Children's Mercy Hospital; Vice Chair of Pediatrics for Emergency and Urgent Care; Professor of Pediatrics and Emergency Medicine, University of Missouri-Kansas City School of Medicine

Gregory P Conners, MD, MPH, MBA is a member of the following medical societies: Academic Pediatric Association, American College of Emergency Physicians, American Pediatric Society, American Academy of Pediatrics, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Chief Editor

Timothy E Corden, MD Associate Professor of Pediatrics, Co-Director, Policy Core, Injury Research Center, Medical College of Wisconsin; Associate Director, PICU, Children's Hospital of Wisconsin

Timothy E Corden, MD is a member of the following medical societies: American Academy of Pediatrics, Phi Beta Kappa, Society of Critical Care Medicine, Wisconsin Medical Society

Disclosure: Nothing to disclose.

Acknowledgements

Jeffrey R Tucker, MD Assistant Professor, Department of Pediatrics, Division of Emergency Medicine, University of Connecticut School of Medicine, Connecticut Children's Medical Center

Disclosure: Merck Salary Employment

Mary L Windle, PharmD Adjunct Associate Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Nothing to disclose.

References
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  2. Newman N, Jones C, Page E, Ceballos D, Oza A. Investigation of Childhood Lead Poisoning from Parental Take-Home Exposure from an Electronic Scrap Recycling Facility - Ohio, 2012. MMWR Morb Mortal Wkly Rep. 2015 Jul 17. 64 (27):743-5. [Medline]. [Full Text].

  3. Murata K, Iwata T, Dakeishi M, Karita K. Lead Toxicity: Does the Critical Level of Lead Resulting in Adverse Effects Differ between Adults and Children?. J Occup Health. 2008 Nov 6. [Medline].

  4. Centers for Disease Control and Prevention (CDC). Blood lead levels in children aged 1-5 years - United States, 1999-2010. MMWR Morb Mortal Wkly Rep. 2013 Apr 5. 62 (13):245-8. [Medline]. [Full Text].

  5. Canfield RL, Henderson CR Jr, Cory-Slechta DA, et al. Intellectual impairment in children with blood lead concentrations below 10 microg per deciliter. N Engl J Med. 2003 Apr 17. 348(16):1517-26. [Medline].

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  8. Centers for Disease Control and Prevention. Lead. CDC. Available at http://www.cdc.gov/nceh/lead/. February 9, 2015; Accessed: September 4, 2015.

  9. Martínez S, Simonella L, Hansen C, Rivolta S, Cancela L, Virgolini M. Blood lead levels and enzymatic biomarkers of environmental lead exposure in children in Cordoba, Argentina, after the ban of leaded gasoline. Hum Exp Toxicol. 2013 May. 32(5):449-63. [Medline].

  10. Pourmand A, Khedir Al-Tiae T, Mazer-Amirshahi M. Perspective on lead toxicity, a comparison between the United States and Iran. Daru. 2012 Oct 30. 20(1):70. [Medline]. [Full Text].

  11. Lanphear BP, Winter NL, Apetz L, Eberly S, Weitzman M. A randomized trial of the effect of dust control on children's blood lead levels. Pediatrics. 1996 Jul. 98(1):35-40. [Medline].

  12. [Guideline] American Academy of Pediatrics. Recommendations for Preventive Pediatric Health Care. AAP. Available at https://www.aap.org/en-us/professional-resources/practice-support/Periodicity/Periodicity%20Schedule_FINAL.pdf. May 2015; Accessed: September 6, 2015.

  13. Lanphear BP, Hornung R, Ho M. Screening housing to prevent lead toxicity in children. Public Health Rep. 2005 May-Jun. 120(3):305-10. [Medline].

  14. American Academy of Pediatrics Committee on Environmental Health. Lead. Handbook of Pediatric Environmental Health. American Academy of Pediatrics. Elk Grove, IL: AAP; 1999. 131-43.

  15. Centers for Disease Control and Prevention. Preventing Lead Poisoning in Young Children. Atlanta: CDC; 2005. [Full Text].

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  17. Rogan WJ, Dietrich KN, Ware JH, et al. The effect of chelation therapy with succimer on neuropsychological development in children exposed to lead. N Engl J Med. 2001 May 10. 344(19):1421-6. [Medline].

 
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