Mercury Poisoning: Symptoms and Treatment

What is Mercury (Hg)?

Mercury is a liquid silver metal, also known as quicksilver. Mercury is liquid even below freezing, and at one time was commonly used in thermometers. Mercury occurs in ore deposits of cinnabar throughout the world. Cinnabar is the source of the red pigment vermillion, but is also highly toxic.

Mercury has three chemical forms:

• Methylmercury
• Elemental mercury
• Other organic or inorganic mercury compounds

Mercury can also bond with other metals, such as gold. Mercury doesn’t bond with iron, and traditionally was stored and transported in iron containers.

Causes of Mercury Poisoning

Medically, mercury poisoning is known as hydrargyria or mercurialism. Exposure to mercury and mercury poisoning usually happens in one of three ways.

• inhalation of vapors ie coal smoke
• eating seafood high in mercury (methylmercury)
• mercury absorption through the skin

Mercury fumes or vapor in the air can settle on the ground or in water. Fish and other animals can ingest mercury. It then metabolizes into methylmercury in the animal’s body. Many cases of mercury poisoning occur due to eating fish high in methylmercury. Marine mammals such as whales and dolphins have also shown particularly high levels of mercury.

Who is at risk for mercury poisoning?

Anyone can get mercury poisoning. Methylmercury poisoning is especially dangerous to the fetus, and to young children.

Symptoms of Mercury Poisoning

Symptoms of mercury poisoning vary depending on the chemical form of mercury, and the type of exposure. All three forms affect the brain, nervous system, kidneys and other vital organs.

Methylmercury

Methylmercury poisoning can affect children in the womb if the mother consumes a high amount of fish or other animals containing mercury. Often, the mother shows no symptoms. Pregnant women should avoid seafood unless mercury levels are known to be safe. Methylmercury poisoning can also affect adults.

Symptoms of methylmercury poisoning include:

• impaired neurological development in fetuses, infants and children
• acrodynia (pink disease) in children – pain, swelling and pink discoloration in fingers and toes
• impaired brain function
• poor memory
• inability to concentrate
• poor coordination or motor skills
• poor peripheral vision
• muscle weakness
• speech impairment
• sensations such as “pins and needles” in the hands, feet or around the mouth
• Minamata disease, causing vision and hearing impairment, insanity, paralysis and death

Elemental Mercury

Elemental or metallic mercury can enter the body if a person inhales mercury vapors, which are then absorbed by the lungs. Exposure can occur if elemental mercury spills, or products containing mercury break. The risk of elemental mercury poisoning is higher in warm, badly-ventilated areas indoors.

Symptoms of Elemental Mercury poisoning include:

• mood swings
• irritability or nervousness
• extreme shyness or self-consciousness
• insomnia or sleep disorders
• weakness
• muscle spasms or twitching
• headaches
• sensations such as “pins and needles” in the hands, feet or around the mouth
• impaired cognitive function
• kidney damage
• respiratory failure
• death

Other Mercury Compounds

The body can absorb organic mercury compounds such as methylmercury, and inorganic compounds, through the gastrointestinal tract. Inorganic compounds are more difficult to absorb.

Symptoms of Inorganic Mercury Poisoning

• skin rash
• dermatitis
• mood swings
• mental disturbance
• muscle weakness
• memory loss (amnesia)
• digestive problems
• nausea
• gastritis
• kidney damage
• neurological failure
• death

Mercury in Dental Fillings

Although some are concerned about mercury in silver dental fillings, the U.S. Public Health Service says there is “insufficient evidence of a link between dental mercury and health problems, except in rare instances of allergic reaction.” Use of mercury in dental fillings has decreased considerably, due to development of safer, more modern materials.

Treatment of Mercury Poisoning

Treatment of mercury poisoning depends on

• amount of mercury ingested
• the chemical form of mercury
• length of exposure
• type of exposure (inhalation, ingestion, through the skin)
• overall health of the patient

In many cases, removing the source of mercury is enough the begin the body’s healing process. Often, the effects of mercury poisoning are reversible.

When a person has been exposed to elemental mercury or mercury fumes and vapors, decontamination is important. Decontamination includes removal of clothes, washing the body with soap, and flushing the eyes with saline solution.

In extreme cases, the standard treatment is chelation therapy. Chelation removes heavy metals such as mercury, lead and arsenic from the body using a chelating agent such as dimercaptosuccinic acid (DMSA). In cases where neurological damage has occurred, a specialist can assess and treat the patient depending on the symptoms and severity of damage.

Mercury poisoning can be fatal. If you suspect mercury poisoning, contact a doctor or other health professional.