2. Mercury
• Mercury (quicksilver) is the only metal
that is liquid under ordinary conditions.
• Japanese fishing village of Minamata
(1950s): birth defects and neurologic
diseases caused by methylmercury in
contaminated seafood (industrial
discharges into the bay from a nearby
factory).
3. Mercury
HgS in cinnabar.
• electrolytic production of chlorine and caustic soda
• electrical equipment
• thermometers
• fluorescent lamps
• dental amalgam
• artisanal gold
• antiseptics
Thimerosal has been removed from almost all the
vaccines.
Environmental exposure to mercury from the burning
of fossil fuels and the bioaccumulation of
methylmercury in fish is still very important problem
worldwide.
4. Pharmacokinetics
• Elemental mercury is quite volatile
and can be absorbed from the
lungs.
• It is poorly absorbed from the intact
gastrointestinal tract.
• Inhaled mercury is the primary
source of occupational exposure.
5. Pharmacokinetics
Organic short-chain alkylmercury
compounds are volatile and
potentially harmful by inhalation and
ingestion.
Percutaneous absorption of metallic
mercury and inorganic mercury can
be of clinical concern following
massive acute or long-term chronic
exposure.
8. Pharmacokinetics
• Inorganic mercury is excreted
through the urine and feces.
• Most of the inorganic mercury is
excreted within weeks to months,
but a fraction may be retained in
the kidneys and brain for years.
9. Pharmacokinetics
• After inhalation of elemental mercury vapor,
urinary mercury levels decline with a half-life
1-3 months.
• Methylmercury has a blood and whole body
half-life 50 days.
• Methylmercury undergoes biliary excretion
and enterohepatic circulation.
• 2/3 of methylmercury is excreted in the feces.
12. Acute mercury intoxication
• Acute inhalation of elemental
mercury vapors may cause
chemical pneumonitis and
noncardiogenic pulmonary
oedema.
• Acute gingivostomatitis may occur.
• Neurologic sequelae!
13. Acute mercury intoxication
• Acute ingestion of inorganic mercury
salts (mercuric chloride) can ressult
in a corrosive, potentially life-
threatening hemorrhagic
gastroenteritis.
• After hours to days acute tubular
necrosis and oliguric renal failure
occur.
14. Treatment
• Intensive supportive care!
• Prompt chelation with oral or
intravenous unithiol, intramuscular
dimercaprol or oral succimer
diminishes nephrotoxicity after
acute exposure to inorganic
mercury salts.
15. Treatment
• Vigorous hydration may help to
maintain urine output.
• If acute renal failure ensues,
days to weeks of hemodialysis or
hemodiafiltration in conjunction
with chelation may be necessary.
16. Chronic mercury intoxication
Chronic poisoning from inhalation of
mercury vapor results in a classic triad:
• TREMOR
• NEUROPSYCHIATRIC
DISTURBANCE
• GINGIVOSTOMATITIS
17. Chronic mercury intoxication
Tremor usually begins as a fine
intention tremor of the hands.
The face may also be involved.
Progression to choreiform movements
of the limbs may occur.
19. Chronic mercury intoxication
Erethism is a behavioral pattern
that includes:
• insidious change in mood
• shyness, withdrawal, depression
• explosive anger or blushing
20. Chronic mercury intoxication
Low-dose exposure may produce
subclinical neurologic effects.
Gingivostomatitis, sometimes with
loosening of the teeth, may be
reported after high-dose exposure.
21. Chronic mercury intoxication
Overt peripheral neuropathy
is rare.
Evidence of peripheral nerve
damage may be detected on
electrodiagnostic testing.
22. Chronic mercury intoxication
Acrodynia is an uncommon idiosyncratic
reaction to subacute or chronic mercury
exposure (mainly in children).
It is characterized by painful erythema of
the extremities.
It may be associated with hypertension,
diaphoresis, anorexia, insomnia,
irritability, apathy and miliary rash.
24. Chronic mercury intoxication
• Chronic exposure to inorganic
mercury salts (via topical
application in cosmetic
creams) has been associated
with neurological symptoms
and renal toxicity.
25. Chronic mercury intoxication
Methylmercury intoxication affects
mainly the central nervous system:
• paresthesias, ataxia
• hearing impairment
• dysarthria
• progressive constriction of the visual
fields
27. Chronic mercury intoxication
• Methylmercury is a reproductive
toxin.
• High-dose prenatal exposure to
methylmercury may produce
mental retardation and a cerebral
palsy-like syndrome in the
offspring.
29. Chronic mercury intoxication
• Dimethylmercury is a rarely
encountered, but extremely
neurotoxic form of
organomercury.
• It may be lethal in small
quantities.
30. Diagnosis
• history
• physical findings
• confirmatory laboratory testing
The urine mercury concentration
should be <5 mcg/L and whole
blood mercury conc. <5 mcg/L.
31. Prevention
Workplace exposures should
result in urinary mercury
concentrations <35 mcg per
gram of creatinine.
End-of-work-week whole
blood mercury concetrations
less than 15 mcg/L.
32. Prevention
• Pregnant women, nursing mothers
and young children should avoid
consumption of fish with high
mercury levels (swordfish) and limit
consumption of fish with lower levels
of mercury, to no more than 12
ounces (340 g) per week.
34. Treatment
• Dimercaprol should not be used
in treatment of exposure to
elemental or organic mercury.
• Dimercaprol redistributes
mercury to the central nervous
system from other tissue sites.
