In minimal doses, mercury is generally considered safe. However, mercury is a known neurotoxin that can cause many adverse health effects in higher amounts. The most common form of mercury poisoning occurs from consuming fish and seafood containing high levels of mercury.
This article provides an overview of mercury poisoning, symptoms, complications, diagnosis, and treatment.
Causes and Symptoms
Mercury is a neurotoxin that can damage nerve tissue in the body and negatively affect nervous system function. There are different types of mercury poisoning with different symptoms.
Methylmercury
One of the most common types of mercury poisoning comes from exposure to methylmercury. This most commonly occurs when people eat fish or shellfish containing high amounts of methylmercury.
Symptoms of methylmercury poisoning may include:
Muscle weakness Loss of coordination Loss of peripheral vision (side vision) Prickling sensation in the hands, feet, or around the mouth Impairment of speech or hearing Difficulty walking
Metallic Mercury
Another type of mercury poisoning can occur from exposure to vapor from metallic mercury.
This type can occur when metallic mercury breaks or spills and the vapors become exposed to air. Metallic mercury can be found in dental fillings, thermostats, jewelry, and school laboratories.
Breathing in this type of mercury vapor can cause:
Tremors Emotional changes Sleeping difficulties Weakness, muscle twitching, or atrophy (loss of muscle tissue) Headaches Changes in nerve responses Poor thinking ability Impaired kidney function, respiratory issues, or even death (when at high levels)
Other Types of Mercury
Inorganic mercury can sometimes be found in everyday household products such as fungicides, preservatives, antiseptics, skin-lightening products, and anti-aging products.
This type of mercury exposure occurs by being absorbed through the gastrointestinal tract and kidneys and may cause:
Skin rashesMuscle weaknessMood swingsMemory lossMental disturbances
Effects on Infants and Children
Methylmercury exposure can harm infants in the womb when their mothers consume fish or seafood with high mercury levels. This exposure can negatively affect brain and nervous system development.
Children who have been exposed to methylmercury before birth have been known to have difficulties with:
Cognitive thinkingAttentionLanguageFine motor skillsVisual-spatial skills
High levels of prenatal mercury poisoning can also cause a form of cerebral palsy, a group of disorders affecting movement, posture, and muscle tone. Lower doses during pregnancy are more likely to cause neurodevelopmental or cognitive delays.
Mercury poisoning symptoms occurring in children after birth may include:
A pins-and-needles sensation (paresthesias) Loss of coordination (ataxia) Visual and auditory issues Seizures
Diagnosis
Mercury poisoning can be diagnosed with a blood test, urine test, or hair test (for long-term mercury exposure). You will need to see your healthcare provider, who will likely perform a physical exam, ask about your symptoms, and gather information about your past medical history.
Methylmercury positioning—from eating fish and seafood high in mercery—requires a blood test for diagnosis. Urine mercury levels do not help determine this type of mercury poisoning.
Treatment
The first step for treatment requires identifying the source of mercury exposure and removing it.
People with high levels of mercury poisoning in the blood may also be prescribed chelation therapy. Chelation therapy is a medical procedure that involves using chemicals or medications to remove heavy metals and other substances from the body.
A chelating agent can be injected directly into the bloodstream through an IV (intravenous drip) or given as a pill by mouth. The chelating agent binds to mercury and other toxins and exits the body through urination.
Summary
Mercury is a neurotoxin that can cause many adverse health effects at high levels. The most common form of mercury poisoning occurs from consuming high-mercury fish and seafood.
Mercury can damage the nervous system and cause symptoms such as muscle weakness, loss of coordination and peripheral vision, prickling sensations, and more. Methylmercury exposure can negatively affect infants in the womb and adversely affect their brain and nervous system development.
A Word From Verywell
Mercury poisoning can cause many adverse health effects, but there are preventive measures you can take to avoid it. Eating a diet low in high-mercury fish and seafood, properly disposing of devices containing mercury, and being aware of everyday products that can cause mercury poisoning can help.
Fortunately, treatments are available to reverse mercury poisoning and its effects. If you are having symptoms of mercury poisoning, contact your healthcare provider for evaluation and testing.
