eMedicine Specialties > Pediatrics: Cardiac Disease and Critical Care Medicine > Toxicology

Toxicity, Lead: Differential Diagnoses & Workup

Author: Mohamed K Badawy, MB, BCh, MD, Assistant Professor, Departments of Emergency Medicine and Pediatrics, University of Rochester and Golisano Children's Hospital at Strong Memorial Hospital
Coauthor(s): Gregory P Conners, MD, MPH, MBA, Interim Chair of Emergency Medicine, Professor of Emergency Medicine and Pediatrics, Departments of Emergency Medicine and Pediatrics, University of Rochester School of Medicine and Dentistry
Contributor Information and Disclosures

Updated: Nov 12, 2008

Differential Diagnoses

Anemia, Acute
Anemia, Chronic
Constipation
Failure to Thrive
Growth Failure
Hydrocarbon Inhalation Injury

Other Problems to Be Considered

Heavy metals poisoning

Workup

Laboratory Studies

The following studies may be indicated in patients with lead poisoning:

  • 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 that may be present in co-ingestions.
  • A CBC count 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 be the beginning for the development of inappropriate secretion of antidiuretic hormone.
  • Whole blood lead level (BLL) is the criterion standard for confirming the diagnosis of lead poisoning. A BLL of 10 mcg/dL or higher denotes 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.
  • Erythrocyte protoporphyrin (EP) may be obtained in selected patients: Lead toxicity affects heme synthesis at several steps, including 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.
  • 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.

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

More on Toxicity, Lead

Overview: Toxicity, Lead
Differential Diagnoses & Workup: Toxicity, Lead
Treatment & Medication: Toxicity, Lead
Follow-up: Toxicity, Lead
References
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References

  1. 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. Nov 6 2008;[Medline].

  2. American Academy of Pediatrics Committee on Environmental Health. Lead exposure in children: prevention, detection, and management. Pediatrics. Oct 2005;116(4):1036-46. [Medline]. [Full Text].

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

  4. 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. Apr 17 2003;348(16):1517-26. [Medline].

  5. CDC. Preventing Lead Poisoning in Young Children. CDC, United States Department of Health and Human Services:1991. [Full Text].

  6. CDC. Screening Young Children for Lead Poisoning. Guidance for State and Local Public Health Officials. Atlanta, GA: United States Department of Health and Human Services; 1997:[Full Text].

  7. 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. May 10 2001;344(19):1421-6. [Medline].

  8. 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. Jul 1996;98(1):35-40. [Medline].

  9. Florin TA, Brent RL, Weitzman M. The need for vigilance: the persistence of lead poisoning in children. Pediatrics. Jun 2005;115(6):1767-8. [Medline].

  10. Graeme KA, Pollack CV. Heavy metal toxicity, part II: lead and metal fume fever. J Emerg Med. Mar-Apr 1998;16, No.2:171-177. [Medline].

  11. Koller K, Brown T, Spurgeon A, Levy L. Recent developments in low-level lead exposure and intellectual impairment in children. Environ Health Perspect. Jun 2004;112(9):987-94. [Medline].

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

  13. Markowitz M. Lead poisoning. Pediatr Rev. Oct 2000;21(10):327-35. [Medline].

  14. Moss ME, Lanphear BP, Auinger P. Association of dental caries and blood lead levels. JAMA. Jun 23-30 1999;281(24):2294-8. [Medline].

  15. Schaffer SJ, Campbell JR. The new CDC and AAP lead poisoning prevention recommendations: consensus versus controversy. Pediatr Ann. Nov 1994;23(11):592-9. [Medline].

  16. Tong S, von Schirnding YE, Prapamontol T. Environmental lead exposure: a public health problem of global dimensions. Bull World Health Organ. 2000;78(9):1068-77. [Medline].

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Further Reading

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Keywords

lead toxicity, plumbism, blood lead level, BLL, lead poisoning, lead-based paint, paint chips, lead encephalopathy, anorexia, vomiting, constipation, abdominal pain, hyperactivity, respiratory depression, hypertension

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Contributor Information and Disclosures

Author

Mohamed K Badawy, MB, BCh, MD, Assistant Professor, Departments of Emergency Medicine and Pediatrics, University of Rochester and Golisano Children's Hospital at Strong Memorial Hospital
Mohamed K Badawy, MB, BCh, MD is a member of the following medical societies: Ambulatory Pediatric Association, American Academy of Pediatrics, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Coauthor(s)

Gregory P Conners, MD, MPH, MBA, Interim Chair of Emergency Medicine, Professor of Emergency Medicine and Pediatrics, Departments of Emergency Medicine and Pediatrics, University of Rochester School of Medicine and Dentistry
Gregory P Conners, MD, MPH, MBA is a member of the following medical societies: Ambulatory Pediatric Association, American Academy of Pediatrics, American College of Emergency Physicians, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Medical Editor

William T Zempsky, MD, Associate Director, Assistant Professor, Department of Pediatrics, Division of Pediatric Emergency Medicine, University of Connecticut and Connecticut Children's Medical Center
William T Zempsky, MD is a member of the following medical societies: American Academy of Pediatrics
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Pfizer Inc Stock Investment from broker recommendation; Avanir Pharma Stock Investment from broker recommendation

Managing Editor

Jeffrey R Tucker, MD, Assistant Professor, Department of Pediatrics, Division of Emergency Medicine, University of Connecticut and Connecticut Children's Medical Center
Jeffrey R Tucker, MD is a member of the following medical societies: American Academy of Clinical Toxicology, American Academy of Pediatrics, and Massachusetts Medical Society
Disclosure: Merck Salary Employment

CME Editor

Paul D Petry, DO, FACOP, FAAP, Consulting Staff, Freeman Pediatric Care, Freeman Health System
Paul D Petry, DO, FACOP, FAAP is a member of the following medical societies: American Academy of Osteopathy, American Academy of Pediatrics, American College of Osteopathic Pediatricians, and American Osteopathic Association
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, and Wisconsin Medical Society
Disclosure: Nothing to disclose.

 
 
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