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Childhood lead poisoning: Clinical manifestations and diagnosis

Author
Jennifer A Lowry, MD
Section Editors
Donald H Mahoney, Jr, MD
Michele M Burns, MD, MPH
Jan E Drutz, MD
Deputy Editor
James F Wiley, II, MD, MPH

INTRODUCTION

The clinical manifestations and diagnosis of lead toxicity will be reviewed here.

Prevention and treatment of lead poisoning are discussed separately. (See "Childhood lead poisoning: Exposure and prevention" and "Childhood lead poisoning: Management".)

EPIDEMIOLOGY

Lead (Pb), a stable metallic element with an atomic number of 82 and atomic weight of 207, was first smelted around 4000 BC as a by-product of silver processing [1]. The consequences of lead toxicity have been recognized for millennia [2]. Despite this knowledge, lead was included as an ingredient of gasoline in the 1920s and continued to be used in paint in some developed countries until the 1970s [3,4]. In many low-income countries, lead in gasoline and industrialized uses of lead (eg, smelters, mines, or refineries) remain major sources of exposure [1]. About 50 percent of the worldwide burden of lead poisoning occurs in Southeast Asia [5]. In 2004, 16 percent of all children in the world were estimated to have blood lead levels (BLLs) >10 mcg/dL (0.48 micromol/L) with 90 percent of children with elevated levels living in low-income regions [1].

Risk factors, sources, and prevention of childhood lead poisoning include:

Risk factors – Children younger than six years of age (and particularly those younger than 36 months) are more susceptible to the toxic effects of lead than are adults because they have an incomplete blood-brain barrier that permits the entry of lead into the developing nervous system and because they have a greater prevalence of iron deficiency, which can result from and cause lead poisoning through increased absorption of lead from the gastrointestinal tract [6-8]. In addition, they are at greater risk of exposure to lead dust because of crawling, higher respiratory rates, and hand-to-mouth behavior.

                       

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