Neurotoxicity is damage to the central or peripheral nervous system that may occur from exposure to toxic substances.

Exposure to certain toxins, such as heavy metals, pollutants, or certain medications, may damage nerve cells. This can affect how the nervous system functions and cause a range of neurological symptoms.

Some immunotherapies can cause neurotoxicity and lead to a condition known as immune effector cell-associated neurotoxicity syndrome (ICANS).

This article looks at the symptoms, causes, diagnosis, and treatment of neurotoxicity, as well as the specific effects of ICANS.

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Neurotoxicity can occur due to exposure to neurotoxins, which are natural or manmade substances that harm the nervous system.

This may cause a range of neurological symptoms, which are symptoms relating to the nervous system. This includes the brain, spinal cord, and nerves throughout the body.

Neurotoxins can impair how the nervous system functions and may affect movement, behavior, and cognitive abilities.

Symptoms of neurotoxicity include dysfunction relating to the nervous system, such as:

Symptoms may develop immediately after exposure to a neurotoxin or they can develop over time. In rare cases, neurotoxicity is life threatening.

Exposure to toxic substances, either manmade or natural, may cause neurotoxicity. These include:

Certain medications, such as some cancer treatments, may cause neurotoxicity. It can occur as a side effect of:

A range of cancer treatments may cause neurotoxicity, including anti-angiogenic treatments and immunotherapy drugs, such as immune checkpoint inhibitors.

A 2020 study, which included 84 participants, found that chimeric antigen receptor-modified (CAR)-T cell therapy, a lymphoma treatment, caused neurotoxicity in 43% of people.

According to a 2020 article, neurotoxicity may be present if there is at least one neurological sign or symptom following exposure to a neurotoxin.

To diagnose neurotoxicity, doctors may carry out a range of tests to check neurological function. These can include:

  • motor function tests
  • neuropathology tests to check for disorders of the nervous system, such as tissue samples
  • cognitive testing, such as memory, learning, or language tests
  • nerve conduction velocity tests, which measure the movement of electrical signals through a nerve to check nerve function
  • imaging tests, such as MRI scans, and cerebrospinal fluid analysis

Treating neurotoxicity may depend on the underlying cause. If certain medical treatments, such as immunotherapy drugs, are causing neurotoxicity, corticosteroids may help resolve and reverse the neurotoxicity.

Chelation therapy may also be a treatment option for removing heavy metal toxins from the body and treating neurotoxicity. This therapy uses materials such as ethylenediaminetetraacetic acid (EDTA) that bind to toxins and remove them from the body.

Avoiding or protecting the body from neurotoxin exposure where possible may help prevent neurotoxicity. Preventive steps include:

  • avoiding exposure to toxins where possible, including heavy metals, solvents, industrial products, and pollutants
  • avoiding smoking or exposure to second-hand smoke
  • maintaining a healthy lifestyle, with a balanced diet and regular exercise
  • avoiding eating any food that neurotoxic substances may have contaminated

Early recognition of symptoms and prompt treatment may help to prevent neurotoxicity from progressing further and stop long-term damage.

If a person is using medication that has a risk of neurotoxicity, it is best to report any new symptoms to a doctor and make sure to follow up regularly for surveillance testing.

ICANS is a potential complication of certain immunotherapies, including CAR-T cell therapy. People with certain blood cancers, such as lymphoma, may receive CAR-T cell therapy.

According to a 2022 article, around 20% to 70% of people having CAR-T cell therapy may develop ICANS. This is a type of neurotoxicity that can be life threatening.

Symptoms of ICANS include:

  • headache
  • confusion
  • difficulty finding words
  • trouble paying attention
  • seizures
  • loss of consciousness

ICANS typically develops within 3 to 10 days of CAR-T cell therapy. With treatment, symptoms may resolve in 7 to 10 days, but some people may require longer treatment.

Can neurotoxicity be reversed?

The reversal of neurotoxicity may depend on the extent of damage, the onset of treatment, and the underlying cause.

Cases of ICANS are usually reversible and may resolve on their own or with early treatment.

A 2019 article suggests EDTA chelation therapy may help to remove heavy metal accumulation from the body and, therefore, may reverse the signs and symptoms of neurotoxicity.

What is an example of a neurotoxin?

Neurotoxic substances can include:

  • heavy metals
  • certain cancer treatments, such as chemotherapy, radiation treatment, and immunotherapy drugs
  • pathogens, such as bacteria and viruses
  • pollutants
  • solvents and industrial products

How long does it take for neurotoxicity to go away?

The duration of neurotoxicity may depend on the cause and treatment. A 2020 study found that neurotoxicity lasted for an average of 6 days in people following CAR T-cell therapy.

Chelation therapy for neurotoxicity may require long-term, regular treatments, sometimes over a course of years, to reduce heavy metal toxins in the body.

Neurotoxicity is damage to the nervous system due to exposure to neurotoxic substances, such as certain medications and environmental toxins.

Prompt treatment may help to resolve and reverse neurotoxicity and prevent further damage. If people have any signs of neurotoxicity, they will need to seek medical attention as soon as possible.