1. 3rd National Congress of Emergency Medicine
MERCURY POISONING:
An Experience in HUSM
Dr. Rashidi Ahmad. MD (USM), Mmed (USM)
Lecturer/Consultant Emergency Physician
School of Medical Sciences
USM Health Campus, Kelantan 1
17th Nov 2007

2. Mercury the Metal
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3. Environmental Sources of Mercury
• Natural Degassing of the earth
• Combustion of fossil fuel
• Industrial Discharges and Wastes
• Incineration & Crematories
• Dental amalgams
Hg0 Hg2+ CH3Hg+
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4. The Mercury Cycle
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5. 5

6. Mercury pollution in the Amazon
• Gold mining—sediments of a river are
run through sluice boxes with mercury
in them. The gold sticks to the mercury
and then the mercury-gold goop is
cooked over a fire to drive off the
mercury, leaving the gold
• Mercury goes to water and air
• Altered vision in study of children along
Rio Tajapos river in Brazil
? Similarly it can happens at Rusila, Terengganu
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7. The many forms of mercury
ORGANIC INORGANIC
SHORT CHAIN ARYL ELEMENTAL MERCURIC
ARKYL COMPOUND SALT
LONG CHAIN
ARKYL
* Methyl mercury (organic) – most toxic
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8. Mercury
• Toxic in any forms
• The difference lies in how it is absorbed,
the clinical signs and symptoms, and
the response to treatment modalities.
• Mercury poisoning can result from vapor
inhalation, ingestion, injection, or
absorption through the skin.
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9. Historical awareness
“Mad as a Hatter”
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10. 10

11. Outbreaks of MeHg Poisoning
Place Year Cases
Minamata 1953-60 1000
Nigata 1964-65 646
Guatemala 1963-65 45
Ghana 1967 144
Pakistan 1969 100
Iraq 1956 100
Iraq 1960 1,002
Iraq 1971 40,000
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On-going 2001 ???

12. Organic Mercury Poisoning
• Minimata, Japan, 50 years
ago…
• Seafood from the bay was
polluted with mercury from an
industrial source
• Neurotoxicity – CP
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13. Seed Grain Outbreaks
• Mercury compounds
applied as antifungal
agent to seed grains
• Iraq—made bread directly
from treated seed grain
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14. Iraq mercury contaminated seed grain – CP
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15. Neurobehavioral Effects
• Blindness – Deafness
• Cerebral Palsy – Seizures
• Retarded motor development
• Visual and Auditory Deficits
• Delayed motor development
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16. Hg and Heart Attacks
• Case-control study showing higher
mercury in men who had heart attacks
vs. controls
“Mercury, Fish Oils, and the Risk of Myocardial
Infarction”. New England Journal of Medicine. 2002
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17. The harmful effects
• Organic mercury - Most devastating to
the CNS
– Short-chained (methylmercury) - Affects the CNS
– Long-chained - Subacute/chronic effects similar to that
of inorganic mercury exposure
• Elemental mercury - Primary neurologic toxicity
• Inorganic mercury salts
– Acute - Severe corrosive gastroenteritis, acute tubular
necrosis
– Subacute or chronic - GI, neurologic, and renal
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dysfunction

18. Introduction
• Mercury poisoning is usually
misdiagnosed [insidious onset, nonspecific s/sx & lack
of knowledge within the medical profession]
• Most recently, 2 areas have caused
public concern regarding mercury
toxicity
- the potential risk associated with eating fish, especially
when dealing with pregnancy
- the use of dental amalgams, or fillings, by dentists.
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Mercury poisonong. www.e-medicine.com

19. Pathogenesis
• Unclear
• Induce auto-immunity
• High affinity towards sulfur group
– Haemoglobin
– IgG, helper CD4+ cells, NK cells
– Mitochodrial function esp in neurons
– Inhibit transport proteins
The Journal of Immunology, Vol 140, Issue 3 750-754 19

20. Accidental Mercury Inhalation:
An Experience in HUSM
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21. Learning objectives
• To highlight the possible clinical
features and possible complications
• To describe the effects of elemental
mercury vapor
• To highlight salient points from various
literatures pertaining to the
management of mercury poisoning.
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22. 17th August 2006 – 3 pm at ED HUSM
• 17 employees of pharmaceutical factory
were rushed to HUSM after alleged
inhalational mercury poisoning.
• Mercury contained thermometer broke in
a beaker with boiled water in a closed
laboratory environment.
• Released mercury vapor was inhaled by
the lab staff.
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23. Demographic Data
Gender 15 female, 2 male
Mean age 30.6 years
Premorbid PID – 1
Pregnancy – 2 (33/52 & 28/52
POA)
Race Malay
Occupation Lab technicians
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24. Symptoms
Sore throat 7
Chest discomfort 1
Dizziness 3
Eye itchiness 1
N&V 2
Metallic taste 2
SOB 1
Asymptomatic 2
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25. Physical examination
• Anxious, tachypneic
• No skin manifestation
• 1 patients showed intention tremor
• 1 patient had reddish sclera of the R eye
• 7 patients had injected throat
• Lungs – clear
• CVS – S1S2, no murmur
• Per abdomen – soft non-tender
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26. Triage parameters
• Conscious, alert, tachypneic, pink
• Normal blood pressure and heart rate
• SaO2 97 – 99%
• Afebrile
Fast track – assigned isolated
ward
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27. Investigations
• FBC – Normal
• BUSE /RFT/ LFT– Normal
• ABG (n = 2) - Normal
• ECG – Normal sinus rhythm
• Whole blood mercury level : 0.5 – 7.3μg/L
Normal mercury levels are considered to be less
than 10 mcg/L in the blood and less than 20
mcg/L in the urine
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28. 28

29. 29

30. Management
• All patients were treated symptomatically
• Observed in OW for 24 hours with all
symptoms resolved
• Discharged with TCA 1 week to A&E and
planned ante-natal clinics.
• Rx – T. Prednisolone 50 mg daily x 3/7
All patients were asymptomatic upon 1/52 follow-up without
any clinical signs. Repeated CXR were all normal.
All patients were discharged
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31. 31

32. Elemental mercury
• Inorganic, Quicksilver (exist in liquid)
• Occurs naturally in soil and in the
atmosphere from volcanic emissions
• Mercury is extracted and used in
industry, then enters air or water from
pollution
• 13.6 times the weight of water
• Evaporates at room temperature
• Lipid soluble; excreted in urine
• Bacteria change to Methylmercury
US Department of Health and Human Services, Public Health 32
Service, Agency for Toxic Substances and Disease Registry, 1989;
publication no. ATSDR/TP-89/16

33. Elemental Mercury
• Very toxic to the nervous system, also to
kidneys
• But….very poorly absorbed by the GI tract
Inhalation route gives higher exposure
• Mercury in fillings is inorganic
• Alloys with other metal called Amalgam
• Many Industrial uses ( drugs, chemicals,
thermometers, batteries, gold mining)
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34. Mercury inhalation
• 80% of inhaled Hg can be absorbed in blood
(~ t1/2 3 days for single exposure)
• 80-100% lung absorption (WHO, 1991); <1%
GI
• Oxidized to Hg2+ easily binds to sulfhydryl
group on enzymes and other proteins and
membrane disulfide bonds
• Concentrated 10 x higher in brain than
equivalent dose of inorganic mercuric salts
Cases of mercury exposure, bioavailability, and absorption
Michael Gochfeld Environmental and Community Medicine,March 2003 34

35. Effect of acute inhalational of elemental Hg
Sore throat 7
Shortness of breath
Metallic taste Chest 1
discomfort
Pleuritic chest pain
Dizziness 3
Lethargy
Eye itchiness 1
Confusion
N&V 2
Nausea & vomitting
Metallic taste 2
Tremors
SOB 1
Asymptomatic 2
Young J: Mercury. In: Goldfrank LR, ed. Goldfrank's Toxicology Emergencies.
Vol 74. New York: McGraw-Hill; 1994:1051-62. 35

36. Inhalational mercury respiratory toxicity
• Erosive bronchitis and
bronchiolitis with interstitial
pneumonitis
(WHO,1991)
• Atelectasis, emphysema,
haemorrhage and
pneumothorax
(Winship, 1985)
• Mild respiratory symptoms
(Wallach, 1972; Janus and Klein, 1982;
Tsuji et al, 1970)
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37. Long term effect- neurotoxicity
Adult Fetus/children
• Memory loss • Cerebral palsy
• Ataxia • Mental retardation
• Dysarthria • Autism
• Hypoasthesia • Late walking
• Finger tremor
• Alzheimer’s disease
Low dose mercury toxicity and human health, March 2005
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38. Pathogeneis of mercury neurotoxicity
• Selectively accumulates in hippocampus,
basal ganglia, cerebral cortex
• Prevents presynaptic serotonin release and
inhibits serotonin transport; causes
calcium disruptions
• Causes demylinating neuropathy
• Causes abnormal neuronal
cytoarchitecture; disrupts neuronal
migration, microtubules, and cell division
Clarkson, T. The toxicology of mercury. Crit
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Rev Clin Lab Sci 1997; 34(3): 369-403

39. Pregnancy – the risky group
• 117 first term pregnancies in the
mercury exposed group
• Spontaneous abortion (19 cases)
• Stillbirth (3 cases)
• Congenital malformations (5 cases of
spina bifida and 1 case of intra-atrial
defect)
Sikorski et al, 1987
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40. Few words on investigation
• Blood mercury is only useful within 3
days of exposure and it is more reliable
in methylmercury (high concentrations
in RBCs)
• A 24-hour urine specimen is a good
indicator for inorganic mercury
poisoning
• Hair mercury level has no role in acute
Hg toxicity
WHO, 2002
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41. Treatment of inhalational mercury
• No role of inducing emesis
• Oral steroid is a common practice but
without substantial evidence
• Hemodialysis is used in severe cases of
toxicity when renal function has declined
(ATSDR, 2002)
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42. • Most inhalational form are self limited –
recovery without sequalae but fibrosis,
empyema and fatal ARDS has been
reported
Taueg C, et al. Acute and chronic poisoning from residential exposures to
elemental mercury-Michigan, 1989-1990. J Toxicol Clin Toxicol 1992; 30(1): 63-7
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43. • Use chelating agents: symptomatic,
systemic absorption is anticipated,
increased mercury blood or urine levels
– dimercaprol (BAL) d-penicillamine
(DPCN)
– 2,3-dimercaptosuccinic acid
(DMSA)
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44. The identification of mercury
Summary
poisoning is difficult due to vague
toxidrome.
Major target organ in inhalational
mercury poisoning is brain and lung
Pregnant ladies are considered high
risk group
Inhalational elementary mercury
poisoning is self-limited with few
sequelae.
The use of oral steroids in mild
inhalational elemental mercury
poisoning is non-substantial
Only manage severe poisoning in
institutes with well fitted 44
decontamination facilities

45. Conclusion
Mercury distribution and
exposure is a global problem
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