Snapshot A 56-year-old man presents with fatigue, pallor, and abdominal pain. The patient reports memory loss and upon further questioning, reveals that he works at a battery recycling plant. On physical exam, the physician observes the finding seen in the image, as well as noticeable foot drop in both lower extremities. Laboratory testing is significant for a lead level > 10 μg/dL. Introduction Overview lead poisoning is caused by occupational and environmental lead exposure and can cause damage to various body systems treatment may involve chelation therapy Epidemiology Prevalence estimated 1.2 million children in the US estimated 16 per 100,000 employed adults (due to occupation) Demographics children aged 1-5 years children < 3 years at greatest risk most likely to put items containing lead into their mouths adults with occupational exposure to lead or exposure through a hobby Location absorption through respiratory tract, GI tract, and skin distribution to blood, soft tissues, and bones Risk factors age infants and young children more likely to chew paint flaking off walls or consume lead dust from their contaminated hands living in a house built before 1978 with chipped paint occupational exposure in lead-related industries (i.e., battery recycling, manufacturing, construction, and mining) exposure from hobbies involving lead (i.e., car repair, metal soldering, and glazed pottery making) ETIOLOGY Pathophysiology lead inhibits key enzymes in heme synthesis pathway inhibits ferrochelatase and ALA dehydratase leads to ↓ heme synthesis results in ↑ RBC protoporhyrin lead inhibits rRNA degradation causes rRNA to aggregate in RBCs visualized as basophilic stippling of RBCs lead causes toxicity through the generation of reactive oxygen species Presentation Symptoms typically nonspecific, result from lead toxicity irritability headache hyperactivity or lethargy anorexia various body systems affected hematological anemia gastrointestinal intermittent abdominal pain constipation vomiting renal interstitial nephritis CNS memory loss confusion encephalopathy Physical exam lead lines on gingivae at base of the teeth peripheral neuropathy wrist or foot drop pallor Imaging Radiographs indications abdominal x-ray in all children with suspected ↑ blood lead levels findings lead-containing paint chips or other lead-containing objects within the GI tract lead lines on metaphyses of long bones in growing children rarely seen except in cases of severe lead toxicity Studies Serum labs blood lead level most accurate test for lead poisoning ↑ lead level (> 10 μg/dL) on venous blood sample free erythrocyte protoporphyrin (FEP) level ↑ FEP due to inhibition of enzymes involved in hemoglobin synthesis note, iron deficiency anemia may also produce an ↑ in FEP ↓ MCV and TIBC ↑ serum iron and ferritin Histology peripheral blood smear hypochromic microcytic anemia basophilic stippling of RBCs Differential Diagnosis Iron deficiency anemia key distinguishing factor ↓ serum iron and ferritin Treatment Lifestyle prevent further exposure to lead via assessment of environmental and occupational exposure modify children's behavior to decrease hand-to-mouth activity Medical chelation therapy indications blood lead levels ≥ 45 µg/dL modalities succimer (oral agent) first-line penicillamine (oral agent) second-line dimercaprol plus EDTA (parenteral) for severe disease or lead encephalopathy crosses blood brain barrier Complications Developmental delay in children Lead encephalopathy treatment chelation therapy