10 Mercury Poisoning Symptoms
Mercury is a heavy metal that is known to cause toxic and dangerous effects in humans. It exists as elemental mercury in nature, inorganic salts, and organic mercury compounds. Depending on the chemical form, dosage, and time of exposure it can affect different organs and cause mayhem in a person’s body.
Methylmercury is a form of organic mercury that is mostly found in fish and it is very toxic to humans. Usually, people affected by this type of mercury toxicity experience symptoms in a more chronic fashion. As the mercury accumulates in our bodies, the symptoms start to become more evident, especially in the central nervous system (CNS) which is greatly affected by methylmercury poisoning. This form of mercury toxicity is especially important in pregnant women as methylmercury can reach the fetus and cause many neurological complications.
Other forms of mercury toxicity can be due to acute exposure such as vapor inhalation associated with occupational exposure. This form of toxicity usually develops symptoms faster due to the amount of mercury involved. After inhaling mercury, it usually transforms into an inorganic form that can affect the nervous system and the kidneys as well. Mercury can be found in many products like batteries, thermometers, and dental fillings to name a few. It was previously used in many drugs and the clothing industry until its toxic effects (especially in the nervous system) became public knowledge, hence the popular phrase “mad as a hatter”.
1. Fatigue
Fatigue can be described as a general feeling of exhaustion. Usually, this symptom improves with adequate rest, but depending on the source of the problem, it may not improve at all. It can be triggered by exercise, stress, and work-related activities. It is a non-specific symptom that can be associated with many conditions like anemia and anxiety, to name a few.
This is a common finding among people exposed to mercury vapors. Depending on the amount of mercury inhaled, it can develop suddenly but most commonly it develops insidiously over time. This is a classic sign of chronic exposure to mercury that can be seen in factory workers, dental practitioners, and miners as well.
2. Dizziness
Dizziness is defined as the loss of balance and/or the feeling of being lightheaded. It is a subjective sensation that can show up suddenly and may cause a person to feel ill. It is important to try to sit down as soon as possible to prevent falls that could result in serious complications.
This symptom is often described by patients that have been exposed to large amounts of inorganic mercury through inhalation of mercury vapors. Depending on the amount of mercury exposure, dizziness could be an early sign of metal fume fever, which is a condition associated with acute mercury exposure causing fever, chills, fatigue, dizziness, and breathlessness.
3. Headache
A headache is described as the sensation of pain in any region of our head. It is a non-specific symptom associated with many conditions. Depending on the characteristics and nature of the headache, they can be classified into primary headaches (migraines and tension-type headaches to name a few), secondary headaches (traumatic, vascular, and substance-related headaches to name a few), and a third category reserved for neuropathies and other headaches.1Headache Classification Committee of the International Headache Society (HIS). The International Classification of Headache Disorders, 3rd Edition (ICHD-3) – www.ichd-3.org
Even though this is a non-specific symptom, it can be quite common among patients exposed to mercury. People exposed to large amounts of mercury vapors can develop a condition known as metal fume fever. This condition can cause mild headaches and fatigue during the early stages of the disease. Headaches may also be associated with methyl mercury exposure through eating contaminated fish.
4. Abdominal Pain
Abdominal pain is a non-specific symptom associated with many conditions. The location and characteristics of the pain can help to distinguish between different pathologies and it can be very useful information to the clinicians in order to provide an accurate diagnosis.
Mercury salts are another form that this mineral can cause harm to humans. Ingestion of mercury salts such as mercuric chloride causes this metal to accumulate in the gastrointestinal tract. Severe abdominal pain is the most common finding among patients with this kind of mercury intoxication but bloody diarrhea, nausea, and vomiting have also been described.
5. Metallic Taste
Taste is another sense that can be altered by mercury exposure. Being a heavy metal, it makes sense that one of the symptoms of mercury poisoning would be having a metallic and annoying taste of metal in the mouth. Sometimes, it can be described as a bitter or sour flavor in the mouth that can be quite unsettling for the patient experiencing it.
This symptom is most commonly seen in cases of mercury salt ingestion. It can appear just a few hours after the ingestion of mercuric chloride and it can be accompanied by inflammation of the gums and foul-smelling breath.
6. Hearing Loss
Hearing loss can be described as having problems hearing sounds that are usually normal to other people. It can affect one or both ears and it can be described as mild, severe, or profound. Depending on the cause of the diminished hearing acuity, it can happen suddenly or it can have an insidious onset as well.
The main target of mercury toxicity is the central nervous system (CNS). Depending on the type of exposure, symptoms can develop differently but most of the time, patients will present with signs and symptoms of CNS involvement. Usually, the hearing loss associated with mercury poisoning affects both ears and it can even be a cause of deafness.
7. Visual Abnormalities
Many medical conditions might cause problems with the eyesight. Whether it affects visual acuity, color differentiation, or light sensitivity, will depend on the nature of the problem itself. Mercury toxicity is a known cause of visual abnormalities that can even lead to blindness.
The most common eye-related symptom associated with mercury poisoning is having problems with visual acuity. Blurred vision, tunnel vision, and even some abnormalities related to color differentiation have been described as well. Blindness is very rare but may happen depending on the level of neurological damage.
8. Tremors
Tremors are described as involuntary movements of the body. They can be caused by fear, nervousness, extreme muscle tiredness, and even a fever may cause chills which are a form of involuntary muscle contraction to generate heat. On the other hand, other medical conditions like Parkinson’s disease, alcoholism, and other toxicities may cause tremors as well.
Muscle tremors are a common finding associated with organic mercury exposure. This is most commonly seen in methylmercury toxicity after chronic exposure to contaminated fish. This is a sign of nerve involvement and it should be evaluated by a medical professional as soon as possible to prevent further complications.
9. Memory Loss
Memory loss is also known as amnesia. It can be described as having problems remembering events, dates, names, or even people. There are two main types of memory loss. Anterograde amnesia is when an individual has problems making new memories, as seen in patients after major head trauma. On the other hand, retrograde amnesia is when a person struggles to remember past events.
Memory loss is a classic symptom associated with the consumption of fish contaminated with methylmercury. The patient might seem foggy at first but as the neurological damage progresses, it can result in memory loss that interferes with daily activities.
10. Tingling Sensation
Paresthesia is the medical term used to describe an altered sensation on a part of the body that usually manifests as tingling, numbness, or burning without an apparent reason. It can be caused by applying an abnormal pressure to a nerve, which causes the transient feeling of numbness that we experience after crossing our legs for too long or falling asleep on top of our hands. It can also manifest as “pins and needles” sensation that can be a sign of nerve damage.
Organic mercury affects the motor and sensory centers in our brain. As the disease progresses, more symptoms will start to appear and it can produce tingling in the arms or other parts of the body as well. It is important to know that cooking mercury-contaminated fish does not change mercury levels.
