Lead Poisoning

Aka: Lead Poisoning, Lead Intoxication, Lead Toxicity, Painter's Colic, Plumbism, Saturnism, Lead Neurotoxicity Syndrome

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II. Epidemiology

  1. Lead levels in children increased during the 20th century, peaking in the 1970s
  2. Even in the U.S. in 2017, lead levels >5 mcg are seen in more than 500,000 children

III. Causes: Most Common

  1. Lead-based paint and lead contaminated soil account for 70% of cases
  2. Contaminated drinking water and imported goods (e.g. candies, spices, pottery) account for 30% of cases

IV. Causes: General

  1. Home renovation or remodel
    1. Household dust
    2. Paint chips from lead-based paint
      1. Lead-based paint was banned in U.S. in 1978
      2. Older housing is likely to still contain residual lead
  2. Drinking water from lead pipes (or contaminated from lead solder, valves or fixtures)
    1. Restricted use of lead in pipes was restricted as of 1986 in U.S. (but still found in municipal pipes, older homes)
    2. Flint Water Crisis started in 2014 and resulted from lead contaminated water
      1. https://en.wikipedia.org/wiki/Flint_water_crisis
  3. Steel or cast iron bathtubs coated in porcelain glaze
    1. Lead is exposed when porcelain breaks down (lead then leaches into bathwater)
  4. Industrial waste exposure (e.g. soil contaminated with lead)
  5. Residence near busy highway
  6. Regional airport with piston engine aircraft
  7. Tea Kettles and pottery
  8. Vinyl mini blinds
  9. Imported candy (e.g. Tamarind candy from Mexico stored in lead-contaminated ceramics)
  10. Imported eye cosmetics (e.g. Kohl or Surma from India, or other eye cosmetics from Pakistan)
  11. Imported Jewelry or Toys
  12. Parents with occupational exposure (i.e. Take-home exposures)
    1. Lead production or smelting
    2. Battery manufacturing or battery reclamation
    3. Brass, copper or lead foundry
    4. Radiator repair
    5. Scrap handling
    6. Ship and bridge demolition
    7. Old painted metal welding
    8. Thermal paint stripping of old buildings
    9. Old paint sanding
    10. Lead soldering
    11. Ceramic glaze mixing
    12. Cable stripping
    13. Firing range staff
    14. Machining or grinding lead alloys
  13. Pica secondary to Anemia
    1. Eating lead paint or soil
  14. Herbal remedies containing lead
    1. See Lead-Containing Herbal

V. Risk Factors

  1. Children younger than 5 years (esp. 6-12 months, peaking at ages 18-36 months)
  2. Iron Deficiency Anemia (4-5x Relative Risk)
    1. Lead and iron are both absorbed from Gastrointestinal Tract via the same transporter
    2. In Iron Deficiency, the transporter is upregulated and therefore absorbs more lead
  3. Communities with lead-containing water service lines (or poor anticorrosion control, e.g. Flint, MI)
  4. Communities with known elevated blood lead levels
  5. Formula fed infants living in communities with lead contaminated water supplies
  6. Close proximity to current or former industrial plants with lead emissions (batteries, smelting plants)
  7. High poverty regions with older, poorly maintained homes
  8. Immigrants or Refugees
  9. Parent with occupation or hobby that exposes them to lead (see causes below)

VI. Symptoms

  1. Nonspecific even at high levels (45 mcg/dl)
    1. Anorexia
    2. Fatigue
    3. Headache
    4. Abdominal Pain
    5. Constipation
    6. Arthralgias
  2. Very high levels
    1. Vomiting
    2. Agitation
    3. Somnolence
    4. Incoordination
    5. Confusion

VII. Signs

  1. Lead line in gums
  2. Papilledema
  3. Ocular palsy
  4. Wrist Drop
  5. Foot Drop
  6. Slurred speech
  7. Reflex changes
  8. Bradycardia
  9. Hypotension
  10. Mental status changes
    1. Seizures
    2. Delirium
    3. Coma

VIII. Labs: Screening

  1. Blood Lead Level
    1. See below for protocol
    2. May screen lead level with capillary blood test
    3. Confirm all abnormal capillary blood tests with venous blood draw lead level
  2. Indications
    1. Previously universal screening was in place before 1997 in United States
      1. Now screen child considered high risk or all children for whom risk is unknown or uncertain
    2. All Medicaid enrolled or eligible children
      1. Obtain lead level at 12 months and 24 months
      2. Catch-up at age 36-72 months if not already done
    3. All recent Immigrant Children (or Refugees, adoptees)
      1. Initial lead level on arrival in U.S.
      2. Repeat screening in 3-6 months later (for ages 6 months to 6 years old)
    4. High risk children
      1. Identified by CDC, state or local screening recommendations (i.e. high risk zip codes)
      2. Child lives in, visits, or attends child care in a house built before 1950
      3. Child lives in, visits, or attends child care in a house built before 1978 with renovation in last 6 months
      4. Child has sibling or playmate that has Lead Poisoning

IX. Labs: Advanced (indicated for lead level >20 mcg/dl or 0.97 umol/L)

  1. Peripheral Smear
    1. Stippled erythrocytes
  2. Complete Blood Count (CBC)
    1. Microcytic Anemia
    2. Leukocytosis
  3. Iron Deficiency Anemia labs (TIBC, Ferritin)
  4. Reticulocyte Count
  5. Urinalysis
  6. Comprehensive metabolic panel
    1. Metabolic Acidosis with Anion Gap
    2. Labile Serum Glucose (Hypoglycemia, Hyperglycemia)

X. Labs: Other findings suggestive of Lead Toxicity

  1. Urine lead level elevated
  2. Urine microscopy of sediment or renal biopsy
    1. Acid-fast inclusion bodies in tubular nuclei
    2. Pathognomonic for Lead Poisoning
  3. Free Erythrocyte Protoporphyrin (FEP) > 0.6 umol/L

XI. Imaging

  1. Abdominal XRay
    1. Indicated for moderate, high or very high lead level of 20 mcg/dl or greater
    2. Identifies lead remaining in the intestinal tract (radiodense)
  2. Long bone XRay
    1. Epiphyseal lead line

XII. Protocol

  1. Precautions
    1. Education and evaluation should be done at all abnormal lead levels
      1. Counseling regarding common lead exposures and prevention
      2. Nutrition counseling to increase Calcium and iron intake
      3. Evaluate Developmental Milestones and environmental exposures
      4. Formal environmental evaluation
    2. There is no known safe level of lead, and lead plays no beneficial role in human physiology
    3. Even blood lead levels 5 mcg/dl have been associated with permanent neurocognitive and behavioral deficits
  2. Lead level 5-9 mcg/dl (0.24 to 0.43 umol/L): Low Lead Toxicity level
    1. Obtain venous lead level confirmation at one to three months
  3. Lead level 10-14 mcg/dl (0.48 to 0.68 umol/L): Low Lead Toxicity level
    1. Obtain venous lead level confirmation within one month
    2. Lead level at 0 months
    3. Lead level at 3 months
    4. Lead level at 6-9 months
  4. Lead level 15-19 mcg/dl (0.72 to 0.92 umol/L): Low Lead Toxicity level
    1. Obtain venous lead level confirmation within one month
    2. Lead level at 0 months
    3. Lead level at 1-3 months
      1. If lead level still >15 mcg/dl proceed to follow lead level of 20-44 mcg/dl
      2. If lead level <15 mcg/dl, continue with education and observation
    4. Lead level at 3-6 months
  5. Lead level 20-44 mcg/dl (0.97 to 2.13 umol/L): Moderate Lead Toxicity level
    1. Obtain venous lead level confirmation within one month
    2. Lead level at 0 months
      1. Environmental investigation and lead hazard reduction
      2. Complete history, exam, XRay as above
      3. Obtain Hemoglobin, Hematocrit and lead level
      4. Consider bowel Decontamination if ingestion suspected (consider abdominal XRay)
        1. Enemas used to clear retained lead products
    3. Lead level at 2-4 weeks
    4. Lead level at 1 month
  6. Lead level 45-69 mcg/dl (2.17 to 3.33 umol/L): High Lead Toxicity level
    1. Obtain venous lead level confirmation within 48 hours (24 hours if >60)
      1. Complete history, exam, Neurologic Exam, XRay as above
      2. Obtain Hemoglobin, Hematocrit and lead level
    2. Lead level at 0 months
      1. Includes measure done for lead level of 20-44 mcg/dl
    3. Lead level pre-chelation
      1. Outpatient Chelation therapy
    4. Lead level post-chelation
  7. Lead level >70 mcg/dl (>3.38 umol/L): Very high Lead Toxicity level
    1. Obtain venous lead level confirmation emergently
    2. Lead level at 0 months
      1. Includes measure done for lead level of 20-44 mcg/dl
      2. Immediate hospitalization for chelation therapy
    3. Lead level pre-chelation
      1. Inpatient chelation therapy
    4. Lead level post-chelation

XIII. Management: Chronic lead chelation

  1. Precautions
    1. Consult toxicologist (typically poison control in U.S.) before using chelation
    2. Obtain labs and diagnostics as above before chelation
    3. Dosing regimens should be checked with toxicology
  2. First-Line
    1. Succimer or Chemet (Meso-2,3-dimercaptosuccinic acid or DMSA)
      1. Initial: 10 mg/kg (or 350 mg/m2) PO every 8 hours for 5 days
      2. Next: 10 mg/kg (or 350 mg/m2) PO every 12 hours for 14 days
  3. Other Parenteral agents that have been used for lead chelation
    1. Edetate Calcium Disodium (Calcium Disodium Versenate)
      1. Dose: 0.5-1.0 g/m2/day
      2. Maximum: 1.5 grams per day
    2. Dimercaprol (BAL in oil)
      1. Dose: 12-24 mg/kg/day for 5 days
  4. Other oral agents that have been used for lead chelation
    1. Penicillamine (Cuprimine)
      1. Dose: 20-40 mg/kg/day for 3 to 6 months
      2. Maximum: 1 grams per day
  5. Efficacy
    1. Chelation not affective if lead <45 mcg/dl
    2. Dietrich (2004) Pediatrics 114:19-26 [PubMed]

XIV. Management: Acute Lead Chelation

  1. Indications
    1. Acute Encephalopathy (e.g. Seizures, Altered Mental Status) AND
    2. Lead Toxicity confirmed with whole blood lead level
  2. Chelation agents
    1. British anti-Lewisite (BAL)
      1. Administered intramuscular (IM)
      2. Contraindicated in peanut allergy and G6PD Deficiency
    2. Calcium Disodium EDTA
      1. Administered after BAL
      2. Poor CNS penetration
  3. Protocol
    1. Consult poison control
    2. First: British anti-Lewisite (BAL) IM (if not contraindicated)
    3. Next: Calcium Disodium EDTA IV given 4 hours after BAL
  4. References
    1. Swadron and Nordt in Herbert (2016) EM:Rap 16(6): 13-4

XV. Complications: Untreated Lead Poisoning

  1. Aggressive and delinquent behavior
  2. Motor development deficits
  3. Language and cognitive deficits
  4. References
    1. Needlman (1996) JAMA 275:363-9 [PubMed]

XVI. Prevention

  1. Precautions regarding drinking water from lead pipes
    1. Allow tap to flow for 30 seconds, then collect water
      1. Alternatively shower, bath, and flush toilets before using tap water for cooking
    2. Do not use hot water from tap for drinking (use only cold water or bottled water)
    3. Consider formal testing of house tap water for lead
  2. Basic house measures
    1. Wash childrens hands and toys frequently
    2. Wet mop floors and window sills every 2 weeks
    3. Remove shoes before entering house
    4. Avoid folk remedies, imported medicines, candies, pottery (esp. from developing countries)
  3. Avoid living near highways or industrial plants
  4. Eliminate lead exposures (soil, dust, paint, water)
    1. CDC and local data can be used to identify areas for environmental testing (e.g. house paint)
  5. Replace all lead paint with non-lead paints using lead-safe practices
    1. Carefully limit child's exposure during remodeling
    2. Carefully dispose of removed lead paint

XVII. Resources

  1. Lead Poisoning in Children (CDC)
    1. https://www.cdc.gov/nceh/lead/
  2. Drinking Water Contamination (EPA)
    1. https://www.epa.gov/ground-water-and-drinking-water/basic-information-about-your-drinking-water

XVIII. References

  1. Tagliaferro (2023) Crit Dec Emerg Med 37(1): 21-9
  2. (2005) Pediatrics 116(4): 1036-46 [PubMed]
  3. Chao (1993) Am Fam Physician 47:113-20 [PubMed]
  4. Dietrich (2004) Pediatrics 114(1): 19-26 [PubMed]
  5. Mayans (2019) Am Fam Physician 100(1):24-30 [PubMed]
  6. Rogan (2001) N Engl J Med 344(19): 1421-6 [PubMed]
  7. Warniment (2010) Am Fam Physician 81(6): 751-60 [PubMed]

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