Rosen & Barkin's 5-Minute Emergency Medicine Consult (418 page)

• Acute toxicity:
  
  • Most often due to inhalation of an environmental source or ingestion of substance containing lead
    
    • Pottery glaze
      
    • Certain folk remedies
      
    • Cosmetics
      
    • Jewelry
      
    • Weights
      
    • Home-distilled alcoholic beverages
      
    • Lead dust from ammunition and primer
      
• Chronic toxicity:
  
  • Occupational exposures (usually via inhalation):
    
    • Battery manufacturing/recycling
      
    • Bridge painting
      
    • Construction workers
      
    • De-leading
      
    • Electronic waste recycling
      
    • Firing range instructors
      
    • Mining and smelting
      
    • Pottery workers
      
    • Welders
      
  • Home exposures (pediatric poisoning):
    
    • Lead-based paint inhalation/ingestion from toys and walls
      
    • Contaminated water from old pipes
      
    • Lead dust from the clothing of a parent exposed at work
      
    • Imported foods
      
    • Folk medicines
      

DIAGNOSIS

• Neurologic:
  
  • Seizures (may be prolonged and refractory)
    
  • Encephalopathy
    
  • Learning disabilities
    
  • Psychiatric disturbances
    
  • Cerebral edema
    
  • Peripheral motor neuropathy (wrist drop), classic but rare finding in chronic toxicity
    
• GI:
  
  • Colicky abdominal pain (lead colic)
    
  • Ileus
    
  • Nausea/vomiting
    
  • Lead lines on gingival line (Burton lines) appear as bluish tint (indication of lifetime burden, not acute exposure).
    
  • Hepatitis/pancreatitis
    
• Cardiovascular:
  
  • HTN (generally secondary to renal failure)
    
  • Myocarditis and conduction defects
    
• Renal:
  
  • Chronic renal insufficiency with long-term exposure
    
• Hematologic:
  
  • Anemia (due to interference with globin chain synthesis)
    
  • Increases RBC fragility, so decreased RBC life span
    
• Musculoskeletal:
  
  • Lead lines from increased Ca
    ²⁺
    deposition at epiphyses (do not consist of lead itself)
    
  • Decreased bone strength and growth
    

Blood lead level (BLL)

• Whole-BLL:
  
  • There is no normal BLL
    
    • In pediatric cases, educational interventions begin at BLL ≥10 μg/dL
      
    • In pediatric cases, chelation therapy is instituted at BLL ≥45 μg/dL
      
    • In adults, chelation therapy is usually considered at BLL ≥70 μg/dL
      
  • 100 μg/dL may present with severe encephalopathy; cognitive effects increase with rising levels
    
  • Expect that BLL may rise after treatment is completed due to redistribution
    
• CBC:
  
  • For presence of anemia
    
  • RBC indices and iron studies
    
• Electrolytes, BUN, creatinine, glucose:
  
  • For renal insufficiency
    
• Transaminases, liver function tests prior to chelation administration
  
• FEP or ZPP
  

• Plain abdominal radiographs to look for radiopaque foreign body
  
• Long-bone series to look for lead lines (specifically in children)
  
• Cranial CT and other studies as indicated by patient’s condition
  

• Acute toxicity:
  
  • Acute appendicitis/colitis/gastroenteritis
    
  • Celiac disease
    
  • Cholera
    
  • Distributive shock
    
  • Encephalopathy
    
  • Toxic ingestions
    
    • Amanita
      mushroom poisoning
      
    • Cyclic antidepressants or other seizure-inducing toxins
      
    • Organophosphates
      
• Chronic toxicity:
  
  • Addison disease
    
  • Guillain–Barré syndrome or other neuropathy
    
  • Vitamin deficiency (B3, B6, or B12)
    
  • Wernicke–Korsakoff syndrome
    

TREATMENT

• Support airway/breathing and circulation
  
• Cardiac monitoring
  
• Seizure management
  

• ABCs:
  
  • Cardiac monitor
    
  • Isotonic crystalloids as needed for hypotension; vasopressors for refractory hypotension
    
• Naloxone, thiamine, and dextrose (D50W) as indicated for altered mental status
  
• Cardiovascular:
  
  • Isotonic crystalloids to support BP
    
  • Vasopressors for refractory hypotension (rare)
    
• Neurologic:
  
  • Treat seizures with benzodiazepines.
    
  • Assist ventilation for respiratory failure due to neuromuscular weakness.
    
• Renal:
  
  • Hemodialysis for renal failure
    
• Alimentary:
  
  • Dextrose, enteral, or parenteral feeding may be beneficial
    

• Decontamination:
  
  • If opacities are seen on upright abdominal film, institute whole-bowel irrigation at 1–2 L/hr of polyethylene glycol until abdominal films are clear
    
  • Activated charcoal is not effective.
    
• Evaluate need for chelation therapy:
  
  • BLL
    
  • Acuity of exposure
    
  • Clinical symptoms
    
  • Consultation with a medical toxicologist or poison center
    

• Most likely exposures are via inhalation and caused by occupational exposure or ethnic products
  
• Adults with encephalopathy or those with BLL: >100 mg/dL may need chelation
  
  • Begin with dimercaprol (BAL) and continue for 5 days
    
  • Start edetate calcium disodium (CaNa
    ₂
    EDTA) after 2nd dose of BAL
    
• Asymptomatic patients with BLL of 70–100 μg/dL may be treated with an oral chelating agent, succimer (DMSA)
  
• Chelation is not indicated for asymptomatic adults with BLL <70 μg/dL
  

• Currently, BLL ≥10 μg/dL require investigative and educational interventions:
  
  • Investigation into the cause of the exposure and repeat monitoring must occur
    
  • Parental education should be initiated
    
• BLL ≥45 μg/dL:
  
  • Chelation therapy is initiated
    
  • Asymptomatic children are treated with DMSA
    
  • Symptomatic children or those with BLL ≥70 μg/dL are treated with BAL and CaNa
    ₂
    EDTA
    
  • Consult with medical toxicologist/poison center when chelation therapy is considered
    

• Much controversy about fetal lead toxicity
  
• Consult maternal–fetal medicine and medical toxicologist/poison center in pregnant patients with elevated BLL.
  

• Chelating agents:
  
  • Dimercaprol (BAL), 3 mg/kg deep IM q4h for 3–5 days if mild to moderate symptoms; 4 mg/kg IM q4h for 5 days for severe symptoms (seizure, encephalopathy):
    
    • Caution: Contraindicated in patients with peanut allergies
      
  • Edetate calcium disodium (CaNa
    ₂
    EDTA), 50 mg/kg/d as continuous IV infusion (adults and peds) or 1 g/m
    ²
    /d as continuous IV infusion
    
    • Treat for 5 days and start 4 hr after BAL
      
  • Succimer (DMSA):
    
    • Adults: 10 mg/kg PO q8h for 5 days, then q12h for 14 days
      
    • Peds: 350 mg/m
      ²
      q8h for 5 days, then q12h for 14 days
      
• Dextrose 50%: 25 g (50 mL; peds: 0.5 g/kg D25W) IV for hypoglycemia
  
• Diazepam: 5–10 mg (peds: 0.1 mg/kg) IV for seizure control
  
• Lorazepam: 2–4 mg IV or IM
  
• Naloxone: 0.4–2 mg (peds: 0.1 mg/kg) IV
  
• Thiamine: 100 mg (peds: 1 mg/kg) IM or IV
  

FOLLOW-UP

• Symptomatic lead intoxication
  
• Children at high risk for re-exposure in their current environment
  
• Children with difficulty tolerating DMSA
  
• Pregnant patients with elevated lead levels—consult obstetrics and toxicology.
  

• Asymptomatic patients not requiring IV chelation therapy
  
• Chronically exposed patients who do not require admission should be referred for outpatient evaluation
  
• Ensure home environment is safe for patient prior to discharge
  
• Ensure pediatric patients tolerate oral chelation therapy prior to discharge
  

Follow up with medical toxicologist or primary care physician.

• Heel sticks may result in falsely elevated BLL; repeat positive blood tests for confirmation
  
• Secure social worker support to ensure safe home environment prior to discharge
  
• Inquire and test siblings or family members in a patient with lead toxicity
  
• Do not give BAL if patient has peanut allergy
  

• Binns HJ, Campbell C, Brown MJ. Interpreting and managing blood lead levels of less than 10 microg/dL in children and reducing childhood exposure to lead: Recommendations of the Centers for Disease Control and Prevention Advisory Committee on Childhood Lead Poisoning Prevention.
  Pediatrics
  . 2007;120:e1285–e1298.
  
• Centers for Disease Control and Prevention (CDC). Lead poisoning in pregnant women who used Ayurvedic medications from India–New York City, 2011–2012.
  MMWR Morb Mortal Wkly Rep
  . 2012;61:641–646.
  
• Henretig F. Lead. In: Flomenbaum NE, Goldfrank LR, Hoffman RS, et al., eds.
  Goldfrank’s Toxicologic Emergencies
  . 9th ed. New York, NY: McGraw-Hill; 2010.
  
• Levin R, Brown MJ, Kashtock ME, et al. Lead exposures in U.S. Children, 2008: Implications for prevention.
  Environ Health Perspect
  . 2008;116(10):1285–1293.
  
• Lin CG, Schaider LA, Brabander DJ, et al. Pediatric lead exposure from imported Indian spices and cultural powders.
  Pediatrics
  . 2010;125:e828–e835.