Mercury toxicity: Difference between revisions
 
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==Background==
==Background==
*Atomic symbol of Hg from latin name hydrargyros which means silver water
===Historical Exposures===
#'''Hat felters (Elemental)'''
#*"Mad as a hatter"
#Anti-syphilitic agents (Inorganic)
#*"A night in the arms of venus lead to a lifetime on mercury"
#'''Calomel (Inorganic)'''
#*Mercurous Chloride sold as a teething powder
#*Causes "pink disease"
#**pain and erythema of the palms and soles, irritability, insomnia, anorexia, diaphoresis, photophobia, and skin rash
#'''Minamata Bay, Japan (Organic)'''
#*Massive exposure to methylmercury from contaminated seafood secondary to industrial dumping of mercury containing compounds
#'''Iraq 1971 (Organic)'''
#*95,000 tons of methylmercury coated grain sold for human consumption
#'''Miners and smelters (Elemental)'''
#*Mostly secondary to exposure to Cinnabar (HgS)
#'''Dental workers through amalgams (Elemental)'''
#*Clinical effects secondary to exposure to mercury through amalgams is controversial
===Common Exposures===
===Common Exposures===
*Industrial
*Industrial
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*Seafood consumption
*Seafood consumption
**Mostly methylmercury
**Mostly methylmercury
===Exists as three major forms===
===Exists as three major forms===
*All disrupt sulfhydryl ezymes leading to impaired cellular function
*All disrupt sulfhydryl ezymes leading to impaired cellular function
====Elemental====
====Elemental====
*Liquid metal at room temperature (Think of the Terminator recongealing)
*Liquid metal at room temperature (Think of the Terminator recongealing)
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*Poorly absorbed from GI tract  
*Poorly absorbed from GI tract  
**Therefor most ingestions are non-toxic
**Therefor most ingestions are non-toxic
====Organic====
====Organic====
*Exists in three major forms:
*Exists in three major forms:
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*Short chain forms are highly lipophilic and cross the blood-brain barrier and placenta
*Short chain forms are highly lipophilic and cross the blood-brain barrier and placenta
**Metabolized in the liver to N-acetyl-homocysteine-methylmercury which undergoes enterohepatic recirculation
**Metabolized in the liver to N-acetyl-homocysteine-methylmercury which undergoes enterohepatic recirculation
====Inorganic====
====Inorganic====
*Exists as monovalent and divalent  
*Exists as monovalent and divalent  
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**Other dangers exist though!!!
**Other dangers exist though!!!
*The California Department of Public Health issued a health alert on May, 2014 noting mercury poisoning linked to use of skin-lightening or acne Creams from Mexico<ref>http://www.ehib.org/papers/Health_Alert%20_Mercury_Poisonings_from_Mexican_creams_5_2014.pdf</ref>
*The California Department of Public Health issued a health alert on May, 2014 noting mercury poisoning linked to use of skin-lightening or acne Creams from Mexico<ref>http://www.ehib.org/papers/Health_Alert%20_Mercury_Poisonings_from_Mexican_creams_5_2014.pdf</ref>
===Historical Exposures===
''Atomic symbol of Hg from latin name hydrargyros which means silver water''
*Hat felters (Elemental)
**"Mad as a hatter"
*'''Anti-syphilitic agents (Inorganic)'''
**"A night in the arms of venus lead to a lifetime on mercury"
*Calomel (Inorganic)
**Mercurous Chloride sold as a teething powder
**Causes "pink disease"
***pain and erythema of the palms and soles, irritability, insomnia, anorexia, diaphoresis, photophobia, and skin rash
*Minamata Bay, Japan (Organic)
**Massive exposure to methylmercury from contaminated seafood secondary to industrial dumping of mercury containing compounds
*Iraq 1971 (Organic)
**95,000 tons of methylmercury coated grain sold for human consumption
*Miners and smelters (Elemental)
**Mostly secondary to exposure to Cinnabar (HgS)
*Dental workers through amalgams (Elemental)
**Clinical effects secondary to exposure to mercury through amalgams is controversial


==Clinical Features==
==Clinical Features==
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===Elemental Mercury===
===Elemental Mercury===
====Acute Exposure====
====Acute Exposure====
*Metal fume fever
*[[Metal fume fever]]
**Usually self limited course of fever, chills, shortness of breath, metallic taste in throat, lethargy, confusion, vomiting, renal tubular necrosis
**Usually self limited course of [[flu-like illness]]; [[fever]], chills, [[shortness of breath]], metallic taste in throat, [[lethargy]], [[confusion]], [[vomiting]], renal tubular necrosis
***Rarely may progress to respiratory compromise and death
***Rarely may progress to [[respiratory distress|respiratory compromise]] and death
*Worse presentation in children
*Worse presentation in children
**May develop pneumothorax, pneumomediastinum and interstitial emphysema
**May develop [[pneumothorax]], pneumomediastinum and interstitial emphysema
*Small airway obstruction secondary to desquamation
*Small airway obstruction secondary to desquamation


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#Hyperexcitable state/emotional lability
#Hyperexcitable state/emotional lability
*Other findings
*Other findings
**Headache, visual disturbances, peripheral neuropathy, ataxia
**[[Headache]], [[visual disturbances]], peripheral neuropathy, [[ataxia]]
===Inorganic Mercury===
===Inorganic Mercury===
====Acute Exposure====
====Acute Exposure====
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====Chronic Exposure====
====Chronic Exposure====
*Chronic exposures usually secondary to inhalation exposure
*Chronic exposures usually secondary to inhalation exposure
*Symptoms include renal failure, dementia, acrodynia
*Symptoms include [[renal failure]], [[dementia]], acrodynia
**Acrodynia (AKA pink disease) = painful erythema and edema of hands and feet, rash, tachycardia, hypertension and irritability.
**Acrodynia (AKA pink disease) = painful erythema and edema of hands and feet, [[rash]], [[tachycardia]], [[hypertension]] and irritability.
*Neuropsychiatric disturbances
*Neuropsychiatric disturbances
===Organic Mercury===
===Organic Mercury===
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**Acute presentations usually show signs days to weeks after exposure
**Acute presentations usually show signs days to weeks after exposure
*Neuro symptoms predominate
*Neuro symptoms predominate
**Tremor, ataxia, paresthesias, memory difficulties, visual disturbances, hearing loss
**Tremor, [[ataxia]], [[paresthesias]], memory difficulties, [[visual disturbances]], [[hearing loss]]
*May also cause thrombocytopenia and agranulocytosis
*May also cause [[thrombocytopenia]] and [[agranulocytosis]]
*Highly '''fetotoxic'''
*Highly '''fetotoxic'''
**Easily crosses placenta
**Easily crosses placenta
**May lead to severe mental retardation (like those with Minamata disease), developmental delay, ataxia and seizures in offspring
**May lead to severe intellectual disability (like those with Minamata disease), developmental delay, ataxia and seizures in offspring
**Controversy exists over exposure from regular diet
**Controversy exists over exposure from regular diet
***Albacore tuna may contain up to 0.34ppm of organic mercury
***Albacore tuna may contain up to 0.34ppm of organic mercury
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==Evaluation==
==Evaluation==
===Work-Up===
===Work-Up===
*Urine and blood Hg levels
*Urine and blood mercury levels
*CBC
*CBC
*Chem 7
*Chem 7
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===Evaluation===
===Evaluation===
*Urine Hg levels (>25μg/L is elevated) for elemental and organic mercury
*Urine mercury levels (>25μg/L is elevated) for elemental and organic mercury
**Levels >300μg/L usually symptomatic
**Levels >300μg/L usually symptomatic
**Organic mercury poorly excreted
**Organic mercury poorly excreted
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*ABC's
*ABC's
*Decontaminate
*Decontaminate
**Of note, mercury can penetrate through latex and nitrile gloves
===Inhalation injuries===
===Inhalation injuries===
*[[Oxygen]]  
*[[Oxygen]]  
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===[[Caustic injuries]]===
===[[Caustic injuries]]===
*May consider milk or egg whites
*May consider milk or egg whites
**Thought to bind Hg
**Thought to bind mercury
*WBI
*WBI


===Chelation therapy===
===Chelation therapy===
The choice of chelating agent is dependent of the type of mercury poisoning.
*[[Penicillamine]] 250mg PO QID x 1-2wks
*[[Penicillamine]] 250mg PO QID x 1-2wks
**Avoid in renal failure
**Avoid in renal failure
*[[Dimercaprol]] (BAL) 2.5-5mg IM Q6-12hr
*[[Dimercaprol]] (BAL) 2.5-5mg IM Q6-12hr
*DMSA 10mg/kg TID x 5days then 10mg/kg BID x 14days
**Contraindicated in organic mercury poisoning as can paradoxically increase mercury levels
*[[DMSA]] (succimer) 10mg/kg TID x 5days then 10mg/kg BID x 14days


==Disposition==
==Disposition==


==See Also==
==See Also==
*[[Toxicology (main)]]
*[[Heavy Metals]]
*[[Heavy Metals]]


Latest revision as of 06:52, 9 March 2021

Background

Common Exposures

  • Industrial
    • Batteries, fungicide
  • Seafood consumption
    • Mostly methylmercury

Exists as three major forms

  • All disrupt sulfhydryl ezymes leading to impaired cellular function

Elemental

  • Liquid metal at room temperature (Think of the Terminator recongealing)
  • 14x more dense than water
  • Volatile and lipid soluble, therefore rapidly absorbed through lungs (approximately 70-80%)
  • Oxidized rapidly to inorganic form
  • Poorly absorbed from GI tract
    • Therefor most ingestions are non-toxic

Organic

  • Exists in three major forms:
  1. Long chain
  2. Short chain
  3. Aryl
  • Long chain and Aryl forms are rapidly converted to inorganic forms
  • Short chain forms are highly lipophilic and cross the blood-brain barrier and placenta
    • Metabolized in the liver to N-acetyl-homocysteine-methylmercury which undergoes enterohepatic recirculation

Inorganic

  • Exists as monovalent and divalent
  • Corrosive
  • Chronic exposures lead to accumulation in brain and CNS
  • Found in many batteries, little risk of toxicity from the mercury components s/p ingestion
    • Other dangers exist though!!!
  • The California Department of Public Health issued a health alert on May, 2014 noting mercury poisoning linked to use of skin-lightening or acne Creams from Mexico[1]

Historical Exposures

Atomic symbol of Hg from latin name hydrargyros which means silver water

  • Hat felters (Elemental)
    • "Mad as a hatter"
  • Anti-syphilitic agents (Inorganic)
    • "A night in the arms of venus lead to a lifetime on mercury"
  • Calomel (Inorganic)
    • Mercurous Chloride sold as a teething powder
    • Causes "pink disease"
      • pain and erythema of the palms and soles, irritability, insomnia, anorexia, diaphoresis, photophobia, and skin rash
  • Minamata Bay, Japan (Organic)
    • Massive exposure to methylmercury from contaminated seafood secondary to industrial dumping of mercury containing compounds
  • Iraq 1971 (Organic)
    • 95,000 tons of methylmercury coated grain sold for human consumption
  • Miners and smelters (Elemental)
    • Mostly secondary to exposure to Cinnabar (HgS)
  • Dental workers through amalgams (Elemental)
    • Clinical effects secondary to exposure to mercury through amalgams is controversial

Clinical Features

  • Clinical presentation highly dependent on form, concentration and duration of exposure
    • Inhalation of elemental mercury and ingestion of inorganic can cause acute or subacute toxicity
    • Organic mercury more likely causes chronic toxicity

Elemental Mercury

Acute Exposure

Chronic Exposure

  • Classic Triad:
  1. Tremor
  2. Gingivitis/stomatitis
  3. Hyperexcitable state/emotional lability

Inorganic Mercury

Acute Exposure

  • Primarily toxic through oral route
  • Causes caustic burns
    • Severity dependent on type [Hg(2)Cl vs Hg(1)Cl] and concentration of mercurial salts
      • Mercuric forms [Hg(2)] more toxic
    • Other symptoms include pain, nausea, hematemesis, hypovolemia, acute tubular necrosis
    • Sequelae include renal failure

Chronic Exposure

  • Chronic exposures usually secondary to inhalation exposure
  • Symptoms include renal failure, dementia, acrodynia
  • Neuropsychiatric disturbances

Organic Mercury

  • Acute and chronic exposures present similarly
    • Acute presentations usually show signs days to weeks after exposure
  • Neuro symptoms predominate
  • May also cause thrombocytopenia and agranulocytosis
  • Highly fetotoxic
    • Easily crosses placenta
    • May lead to severe intellectual disability (like those with Minamata disease), developmental delay, ataxia and seizures in offspring
    • Controversy exists over exposure from regular diet
      • Albacore tuna may contain up to 0.34ppm of organic mercury
      • Please see Faroe Island and Seychelles studies
    • Thimerosal (mercury containing preservative found in many vaccines) has NOT been linked to developmental delays or autism

Differential Diagnosis

Heavy metal toxicity

Evaluation

Work-Up

  • Urine and blood mercury levels
  • CBC
  • Chem 7
  • Type and screen
  • Radiographs

Evaluation

  • Urine mercury levels (>25μg/L is elevated) for elemental and organic mercury
    • Levels >300μg/L usually symptomatic
    • Organic mercury poorly excreted
  • Blood levels for organic mercury
  • Hair analysis is not sufficient

Management

  • ABC's
  • Decontaminate
    • Of note, mercury can penetrate through latex and nitrile gloves

Inhalation injuries

Caustic injuries

  • May consider milk or egg whites
    • Thought to bind mercury
  • WBI

Chelation therapy

The choice of chelating agent is dependent of the type of mercury poisoning.

  • Penicillamine 250mg PO QID x 1-2wks
    • Avoid in renal failure
  • Dimercaprol (BAL) 2.5-5mg IM Q6-12hr
    • Contraindicated in organic mercury poisoning as can paradoxically increase mercury levels
  • DMSA (succimer) 10mg/kg TID x 5days then 10mg/kg BID x 14days

Disposition

See Also

External Links

References

  1. ↑ http://www.ehib.org/papers/Health_Alert%20_Mercury_Poisonings_from_Mexican_creams_5_2014.pdf
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