Signs and Symptoms of Chronic Lead Poisoning

Neurological

• Headache, lethargy, irritability, difficulty concentrating
• Cognitive impairment and memory loss
• Peripheral neuropathy — predominantly motor, classically causing wrist drop (extensor muscle weakness) and foot drop
• Ataxia
• In severe or prolonged exposure: lead encephalopathy — tonic-clonic convulsions, cerebral oedema, raised intracranial pressure, opisthotonus
• Children: adverse neurodevelopmental effects — reduced IQ, learning disabilities, behavioral problems (even at subclinical blood levels)

Gastrointestinal

• Anorexia, nausea, vomiting
• Lead colic — severe, colicky abdominal pain
• Constipation or diarrhea
• Metallic taste in the mouth

Hematological

• Microcytic hypochromic anemia (lead inhibits heme synthesis by blocking ALA dehydratase and ferrochelatase)
• Basophilic stippling of red blood cells — a classic finding on peripheral blood smear
• Elevated erythrocyte protoporphyrin (zinc protoporphyrin)

Renal

• Fanconi syndrome (proximal tubular dysfunction) in chronic exposure — aminoaciduria, glycosuria, phosphaturia
• Progressive interstitial nephritis and chronic kidney disease with prolonged exposure
• Hypertension secondary to renal effects

Cardiovascular

• Hypertension
• Increased risk of atherosclerosis and cardiovascular disease (major concern in adults with long-term exposure)

Musculoskeletal

• Myalgia, arthralgia
• Lead lines (Burton's lines) — blue-black discoloration at the gingival margin, due to lead sulfide deposition
• Dense metaphyseal bands ("lead lines") visible on X-ray in children

Reproductive

• Males: reduced sperm count and motility
• Females: increased risk of spontaneous abortion, preterm labor, and fetal developmental toxicity

Endocrine / Other

• Impaired immune function
• Endocrine disruption (thyroid, adrenal effects reported)
• Growth retardation in children

Key Classic Signs at a Glance

Note: The most significant public health consequences are subclinical neurodevelopmental effects in children and cardiovascular disease in adults — both occur without overt symptoms, making blood lead level screening essential (Exposure to Lead, p. 34). There is no known safe blood lead level.