Rosen & Barkin's 5-Minute Emergency Medicine Consult (448 page)

• Ask about possible workplace, environmental, or accidental exposure to mercurial products.
  
• Document the patient’s ingestion of seafood over the last few weeks.
  

• Elemental mercury:
  
  • Cough progressing to respiratory distress if inhaled or intravenously injected
    
  • Ataxia
    
  • Subcutaneous nodules or granulomas if injected
    
• Inorganic mercury:
  
  • Oral burns
    
  • Abdominal tenderness
    
  • Heme-positive stools
    
• Organic mercury:
  
  • CNS abnormalities:
    
    • Progressive cognitive deterioration
      

• Good history for workplace or environmental exposure
  
• Physical exam looking for:
  
  • Respiratory distress
    
  • Caustic GI injury
    
  • Neuropsychiatric impairment
    
• Lab tests:
  
  • Renal failure
    
  • Urine and blood mercury levels:
    
    • Not reliable with recent seafood ingestion
      

• Inorganic mercury exposure:
  
  • CBC
    
  • Electrolytes, BUN, creatinine, glucose
    
  • 24-hr urine mercury collection:
    
    • Normal urine levels <20 mg/dL
      
  • Whole-blood mercury level:
    
    • Normal blood <10 mg/dL
      
• Organic mercury exposure:
  
  • CBC with peripheral smear
    
  • Electrolytes, BUN, creatinine, glucose
    
  • Whole-blood mercury level:
    
    • Normal blood <10 mg/dL
      

• Chest radiograph:
  
  • For noncardiac pulmonary edema
    
  • Evidence of IV mercury in pulmonary vascular tree
    
• Abdominal radiograph:
  
  • For presence of mercury with intentional oral ingestion
    
• Head CT:
  
  • May detect cerebellar atrophy
    

Lumbar puncture in the workup of altered mental status

• Multisystem involvement is often confused with other heavy-metal intoxications.
  
• Cerebrovascular accident
  
• Senile dementia, Alzheimer disease
  
• Parkinson disease
  
• Peptic ulcer disease
  
• Gastrointestinal bleeding
  
• Pancreatitis
  
• Sepsis
  
• Acute respiratory distress syndrome
  

TREATMENT

• Remove from toxin exposure.
  
• Decontamination:
  
  • Wash exposed skin.
    
• For altered mental status:
  
  • Dextrose
    
  • Thiamine
    
  • Naloxone (Narcan)
    
  • Oxygen
    

• Secure ABCs and monitoring.
  
• 0.9% NS
  
• IV fluid resuscitation for hypotension:
  
  • Blood transfusion for significant gastrointestinal hemorrhage
    
• Naloxone, D
  ₅₀
  W, thiamine for altered mental status
  

• Elemental mercury:
  
  • For inhalation exposure, observe closely for several hours for development of noncardiogenic pulmonary edema.
    
  • Ingested elemental mercury passes through normal intestinal tract with minimal absorption.
    
  • Consider chelation for symptomatic patients with oral dimercaptosuccinic acid (DMSA).
    
  • For subcutaneous nodules/abscess, perform an incision and drainage.
    
• Inorganic mercury salt ingestion:
  
  • Administer activated charcoal.
    
  • Aggressive 0.9% NS IV fluid resuscitation/blood products for hypovolemic shock:
    
    • Hydrate and maintain urine output (1 mL/kg/h).
      
  • Chelate symptomatic patients:
    
    • IM dimercaprol (British anti-Lewisite [BAL])
      
    • Oral DMSA efficacy may be limited secondary to caustic GI injury.
      
• Organic mercury:
  
  • Administer activated charcoal.
    
  • Chelate with oral DMSA.
    

• Dextrose: D
  ₅₀
  W 1 amp: 50 mL or 25 g (peds: D
  ₂₅
  W 2–4 mL/kg) IV
  
• Dimercaprol (BAL): 5 mg/kg IM q4h for 48 hr, then 2.5 mg/kg q6h for 48 hr, then 2.5 mg/kg q12h for 7 days
  
• DMSA: 10 mg/kg PO q8h for 5 days, then q12h for 2 wk
  
• Naloxone (Narcan): 2 mg (peds: 0.1 mg/kg) IV/IM initial dose
  
• Thiamine (vitamin B
  ₁
  ): 100 mg (peds: 50 mg) IV or IM
  

• D-penicillamine:
  
  • Adult: 250 mg PO QID for 7–14 days
    
  • Peds: 5–7 mg/kg PO QID for 7–14 days
    
• 2,3-Dimercapto-1-propanesulfonate:
  
  • IV or PO formulations. Contact your poison center at 1-800-222-1222 for availability.
    

FOLLOW-UP

Acutely symptomatic patients:

• Any evidence of respiratory compromise
  
• Ingestion of inorganic mercury salt that may lead to a caustic GI injury
  
• Renal impairment
  
• Any patient starting chelation therapy
  

• Asymptomatic patient with history of ingestion of elemental mercury and intact intestinal tract
  
• Patient with history of inhalation exposure to elemental mercury who remain asymptomatic after 6 hr of observation
  

• Medical toxicology referral for symptomatic patients or where chelation is considered
  
• Gastroenterology for caustic GI injury
  
• Pulmonary/ICU care for patients with symptomatic inhalational injury
  
• Neurology in the evaluation of progressive cerebral deterioration
  
• Poison center for all suspected exposures
  

• For discharged patients with possible workplace or environmental exposures, follow up with their primary care provider for results of 24-hr urine or whole-blood mercury levels.
  
• Outpatient referral to medical toxicology for suspected or confirmed cases
  
• For the asymptomatic patient, have the patient refrain from eating seafood for 2 wk before repeating the 24-hr urine for mercury.
  

• Obtain a good history for workplace, environmental or accidental exposure in patients with gastrointestinal and/or neuropsychiatric complaints.
  
• Monitor patients for at least 6 hr if they were exposed to inhalational elemental mercury.
  
• Ingestion of inorganic mercurial salts can lead to significant caustic GI injury.
  
• Lab tests may yield false positives especially in patients who eat seafood.
  

• Clarkson TW, Magos L, Myers GJ. The toxicology of mercury–current exposures and clinical manifestations.
  N Engl J Med
  . 2003;349:1731–1737.
  
• Rocha JB, Aschner M, Dórea JG, et al. Mercury toxicity.
  J Biomed Biotechnol.
  2012;2012:831890.
  
• Young-Jin S. Mercury. In: Flomenbaum NE, Goldfrank LR, Hoffman RS, et al., eds.
  Goldfrank’s Toxicologic Emergencies.
  9th ed. New York, NY: McGraw-Hill; 2010.
  

See Also (Topic, Algorithm, Electronic Media Element)

• Respiratory Distress
  
• Caustic Ingestion
  
• Renal Failure
  
• Psychosis, Medical vs. Psychiatric
  

CODES

• 961.2 Poisoning by heavy metal anti-infectives
  
• 976.0 Poisoning by local anti-infectives and anti-inflammatory drugs
  
• 985.0 Toxic effect of mercury and its compounds
  

BASICS