8. 3 forms of mercury
Organic:
Elemental / inorganic salts organic Hg
Inorganic: Hg + other elements compound or salts
used in industry, cosmetic skin creams
Elemental Hg inorganic Hg in the body
Elemental: quick silver, thermometer, fluorescent light
bulb, electrical switch, dental amalgam
Microorganism in water/ soil
9. How people are exposed to Hg ?
Elemental Hg: breath elemental Hg vapors (dental
office, smelting operation, Hg spilled or released )
Inorganic Hg: Hg salts are used
Organic Hg: seafood consumption (fish, shellfish
contaminated with methylmercury), pass through
the placenta , breast milk
13. Pathophysiology
Binding to sulfur
Replacing hydrogen ion in sulfhydryl groups
React with phosphoryl, carboxyl and amide group
widespread enzymes dysfunction
14. Pathophysiology
Mercury salt poisoning: necrosis of GI mucosa and
proximal renal tubules (shortly after exposure)
Mercurial ointments use: membranous
glomerulonephritis, acrodynia
Methyl mercury poisoning:
– fetal Minamata disease: atrophy of the cerebellar
hemispheres, postcentral gyri, calcarine area ataxia,
sensory neuropathy, visual field constriction
– Less severe in adult
16. Elemental mercury
Common in occupational setting
Max. limit of ambient air concentration 0.9
mg/m3 (0.1 mg/m3)
Children is more sensitive to mercury vapor:
minute ventilation to body size
Direct aspiration of metallic mercury: massive
endotracheal hemorrhage
Vacuuming spilled mercury
18. Amalgam (elemental Hg)
"Amalgam is not a true alloy. It is made up of 50% mercury, which is not locked
into a set filling but escapes continuously during the entire life of the filling in the
form of vapor, ions and abraded particles“
Australasian Society Of Medicine And Toxicology
19. Amalgam: advantages vs disadvantages
Patient
Durable and cheap
Low rate of local side effect
No conclusive evidence for
systemic adverse effect
Environmental & health care
provider
Decreased exposure due to
good conduct and Hg
hygiene protocols
Environmental impact of
dental amalgam is almost
insignificant
J Ir Dent Assoc. 2013 Dec-2014 Jan;59(6):311-7.
20. Inorganic mercury
Ingestion: caustic gastroenteritis, grayish
discoloration of mucous membrane, metallic taste
Renal: oliguria (within 3 days) from proximal
tubular necrosis
No report of Hg poisoning form button battery
ingestion
Pediatrics. 1992;89:747–757
23. Thimerosal (inorganic Hg)
0.1% thimerosal or 600 mcg/mL Hg
A preservative in multi-dose vials in areas with in
adequate refrigeration
No longer use in the US for routine childhood
vaccines since 2001
Global Alliance for Vaccines and Immunisation.Report to the GAVI Alliance Board Report of the Chief Executive Officer. 2012.
Immunol Allergy Clin North Am.2003;23:589–603.
24. Organic Hg compound
Almost purely permanent neurologic disease
Associated with methylmercury
Lipophilic property
Delayed neurotoxicity (weeks to months)
Detected in breast milk (30% of blood conc.)
25. Source and route of organic Hg exposure
Seafood
FDA limit: 1 ppm for methyl mercury in fish
EPA limit: 0.1 mcg/kg/day
High blood concentration group in self-reported
high consumers of seafood
High risk groups:
– pregnant women or who may become pregnant
– nursing mother
– young children
26. Minamata
Decreased wt. and muscle tone
Profound developmental delay
Seizure
Deafness and blindness
Severe spasticity
28. Diagnostic testing for Mercury
Whole Blood 24-hour Urine Hair Clinical
Elemental/Inorganic (+) (++) (+) (+)
Acute, transient Confirm exposure Reflects past
exposure and
external adsorption
Poor correlation to
total body burden
(TBB)
Monitor chelation Early detection
Poor correlation to
TBB
Organic (++) (–) (+) (+)
Best reflects TBB
(N-acetyl-β-D-
glucosaminidase, β2-
microglobulin)
Fecal elimination Reflects past
exposure and
external adsorption
Poor correlation to
TBB
Reflects irreversible
CNS toxicity
Early detection
29. Hg concentration
Overlap of Hg concentration found in the normal
population, asymptomatic exposed individuals
No correlation between either whole blood or
urine mercury concentration and mercury toxicity
1.0 μg/L or less for whole blood and 0.5 μg/L for
urine are generally considered to exposure in
non-poisoned individuals
Centers for Disease Control and Prevention. Fourth National Report on Human Exposure to Environmental
Chemicals. July 26, 2012. 2009.
30. General management for elemental Hg
Aspiration: postural drainage, ETT suction
Localized injection: surgical excision
Sweep spilled Hg into tightly sealed container
No vacuum for spilled Hg
Broken CFL bulb: EPA guideline / local
requirements
www.pcd.go.th/info_serv/haz_lamp.htm
Opening window to release vapor
Adhesive tape to pick up fragments
31. General management for inorganic Hg
Activated charcoal (AC): substantial adsorption
(800 mcg mercuric chloride: 1 g AC)
Whole bowl irrigation with PEG
Severe gastroenteritis
– Removal over endoscopic evaluation in suspected
penetrating GI mucosal injury
32. General management for organic Hg
Chronic ingestion of contaminated food
Aggressive decontamination: acute ingestion,
dermal exposure
33. Chelation (BAL, DMSA)
Thiol groups in chelators compete with
endogenous sulfhydryl groups for the binding of
mercury
Preventing inactivation of sulfhydryl-containing
enzymes and other essential proteins
Indication:
– history of significant mercury exposure with
– Presence of typical symptoms of mercury poisoning
Urine or blood concentration: unclear cases,
guide the duration of therapy
34. Summary
3 major forms: elemental, inorganic and organic
Large variety of clinical presentation
Neurologic sequelae esp. from organic Hg
exposures : largely irreversible
Promotion of public education and awareness
regarding
– Danger of Hg
– Avoidance
– Proper disposal
Notas do Editor
Neurasthenia is a symptom complex that includes fatigue, depression, headaches, hypersensitivity to stimuli, psychosomatic complaints, weakness, and loss of concentrating ability
Erethism, derived from the Greek word red, describes the easy blushing and extreme shyness of affected individuals.
acrodynia, or “pink disease,” which is an erythematous, edematous, and hyperkeratotic induration of the palms, soles, and face, and a pink papular rash that was first described in a subset of children exposed to mercurous chloride powders.98