Demyelination occurs when myelin, which is the protective coating of nerve cells, sustains damage. When this happens, neurological problems can occur.

Demyelination can result from various medical conditions, including multiple sclerosis (MS).

This article looks at some conditions that cause demyelination, the symptoms that may develop, and the treatment options for each.

Many of the nerves in the nervous system have a coating, or sheath, of myelin, which is a fatty white substance. This myelin sheath protects nerve fibers and enables electrical impulses to pass along nerve cells quickly and efficiently.

How well impulses travel determines how smoothly and quickly a person can perform everyday movements. When something disrupts the myelin sheath, it can cause potentially serious complications with the nervous system.

Some conditions result in damage to the myelin sheath, which can cause problems in the brain, the eyes, the spinal cord, and other parts of the body. Doctors call these conditions demyelinating diseases.

There are several different conditions that can lead to demyelination. The sections below look at some of these in more detail.

MS

In MS, the immune system attacks myelin in the central nervous system, which includes the brain and spinal cord. Experts do not know the exact cause of MS, but they believe that genetic and environmental factors play a role.

Damage to myelin in these areas can result in hardened scars that can appear at different times and in different places. These can lead to various symptoms of demyelination, which can impact a wide range of body functions.

Some common symptoms of MS include:

  • numbness and tingling
  • weakness and fatigue
  • pain
  • vision changes, such as blurry vision or double vision
  • decreased bladder control
  • difficulty with balance and coordination
  • problems with concentration and memory
  • depression

For a small number of people, the symptoms remain mild, but for many others, they can become severe. Most people experience times of relapse, when symptoms worsen for a while, and remission, when symptoms may disappear altogether.

MS usually starts between the ages of 20 and 50 years, and it affects two to three times as many women as men.

Most people with a diagnosis of MS have the same life expectancy as people without MS.

Optic neuritis

Optic neuritis occurs when inflammation and demyelination affect the optic nerve. The optic nerve works to communicate sensory information from the eye to the brain.

Optic neuritis may affect one or both of the eyes. Its symptoms include changes in vision and eye pain.

It is unclear what causes optic neuritis. Experts often link the condition with MS, with the condition — according to one 2016 paper — occurring in about 50% of people with MS. The same paper states that it may also be an initial MS symptom in about 20% of individuals.

Optic neuritis is also more likely to occur in people with viral infections, such as mumps, measles, and the flu.

Neuromyelitis optica

Neuromyelitis optica, or Devic’s disease, occurs when the immune system attacks and destroys myelin in the spinal cord and eye. This can result in symptoms and complications such as:

Many people with neuromyelitis optica have episodes of symptoms that can occur months or years apart. If neuromyelitis optica affects breathing, it can be life threatening.

Like many demyelinating diseases, the cause of neuromyelitis optica remains unknown. However, people who develop the condition often have a personal or family history of autoimmune conditions.

Transverse myelitis

Transverse myelitis refers to inflammation of the spinal cord. When this happens, myelin can sustain damage, leading to symptoms such as:

  • pain and weakness in the limbs
  • unusual sensations, such as burning, numbness, or tickling
  • bladder and bowel problems

In some instances, the cause of transverse myelitis remains unknown. However, the condition may also result from:

Although transverse myelitis can affect people of any age, it most often affects people aged 10–19 years and 30–39 years. Genetics does not appear to play a role in the condition.

Acute disseminated encephalomyelitis

Acute disseminated encephalomyelitis (ADEM) occurs due to widespread inflammation that affects the brain and spinal cord. This can damage myelin and lead to early symptoms such as:

ADEM can also progress to cause symptoms such as vision problems, weakness, and issues with coordination and movement. When ADEM is severe, it can be life threatening, leading to seizures or coma.

The onset of ADEM typically follows a bacterial or viral infection. Less commonly, it can occur following some childhood vaccines. However, some research suggests that the condition is only likely to occur 1.16 times per 1 million vaccine doses.

Adrenoleukodystrophy and adrenomyeloneuropathy

Adrenoleukodystrophy (ALD) is a genetic condition that leads to myelin damage. It has an estimated prevalence of 1 in 20,000 individuals. ALD typically develops during childhood and can lead to symptoms such as:

Adrenomyeloneuropathy (AMN) occurs in adults with the same mutation that causes ALD. It is often milder, begins between the ages of 21 and 35 years, and includes symptoms such as:

  • progressive weakness or stiffness in the legs
  • impaired coordination and movement
  • bladder and bowel problems
  • sexual dysfunction
  • adrenal gland dysfunction (Addison’s disease)
  • peripheral neuropathy

Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is a rare autoimmune condition in which the immune system attacks the nerves of the peripheral nervous system, which includes the nerves outside of the brain and spinal cord. In some forms of GBS, the immune system attacks myelin.

The main symptom of GBS is weakness or numbness and tingling in the legs that often spreads to the arms and torso. In some cases, this may become so severe that paralysis can result. It affects both sides of the body.

Certain infections are known to trigger GBS. One of the most common triggers is an infection with the bacteria Campylobacter jejuni, which causes food poisoning. Experts believe that up to 40% of GBS cases in the United States are due to infections with these bacteria.

Other infections that can lead to GBS include the Epstein-Barr virus, cytomegalovirus, and the flu.

In very rare situations, certain vaccines — such as the flu vaccine — can cause GBS. However, according to the Centers for Disease Control and Prevention (CDC), a person is more likely to get GBS from actually having the flu than from getting a flu vaccine.

Charcot-Marie-Tooth disease

Charcot-Marie-Tooth disease (CMT) also causes damage to the peripheral nerves. It is an inherited condition that results from a genetic mutation that can impact the structure or function of myelin.

Some symptoms of CMT include:

  • weak muscles in the limbs
  • changes to walking, often with frequent tripping or falling
  • foot irregularities, such as high arches or curled toes
  • a reduced ability to feel sensations such as touch and temperature
  • muscle cramping
  • peripheral neuropathy

CMT is progressive, which means that the symptoms gradually become worse. People with the condition typically experience increasing difficulty with movement and carrying out daily tasks.

Demyelinating diseases can affect a wide range of body functions, including the following.

Vision

These conditions can lead to blurry or double vision or a loss of vision that may be temporary or permanent.

Reflexes and movement

Changes to the motor system can lead to muscle weakness, stiffness, spasms, and problems with balance. This can affect movement and make it hard for a person to speak and swallow.

Demyelinating conditions rarely affect involuntary actions, such as breathing and blood pressure.

Senses and feeling

A person may experience numbness and tingling, burning, or prickling sensations in their arms, legs, or feet. They may also feel pain when touched lightly.

A person with MS may notice a symptom that doctors call Lhermitte’s sign. When a person moves their head, they may feel as though an electric shock is passing down the back of their neck, into the spine, and then out through their arms and legs.

Cerebellum

This part of the brain controls balance and coordination. Problems in this area can lead to tremors or incoordination. For example, some people may find that swallowing, writing, eating, and walking become difficult.

Genitourinary system

Some people may experience problems with urination and bowel movements. This can affect sexual health, making it harder to have erections or orgasms. Some people may feel pain during sex, and they may have a higher chance of developing a urinary tract infection.

Mood and thinking

The person may experience depression, anxiety, irritability, and problems with thinking, memory, and focus. Some people may also take longer to process thoughts.

Fatigue

With demyelinating diseases, a person may also experience constant fatigue without any particular cause.

Treatment for demyelinating diseases depends on the specific condition a person has. Below is a list of some possible treatment options.

MS

There is currently no cure for MS, but scientists have made significant progress in recent years. Treatment is now available that appears to reduce the risk of flares and slow the progression of MS for some people.

Current guidelines recommend that doctors prescribe a type of disease-modifying therapy (DMT) from the earliest possible stage when it appears to be most effective. DMT for MS helps reduce the activity of the immune system.

During a time of relapse (when symptoms worsen), steroid treatment can reduce the impact of inflammation. Various medications, including antidepressants and pain relief medications, can help treat specific symptoms. Physical therapy can help with muscle strength as well as coordination and balance problems.

Optic neuritis

Some people with optic neuritis find that the condition improves without treatment. However, most people need some sort of treatment intervention to ease the symptoms or prevent them from worsening.

Corticosteroids are a common treatment for optic neuritis that can help reduce inflammation.

Neuromyelitis optica

Corticosteroids can treat the symptoms of neuromyelitis optica. Additionally, drugs that reduce the activity of the immune system — such as methotrexate and azathioprine — may help prevent future episodes.

Individuals with severe symptoms may also benefit from the use of plasma exchange therapy. This treatment helps remove blood plasma containing autoantibodies, replacing it with fresh plasma that a doctor introduces back into the person’s bloodstream.

Transverse myelitis

Corticosteroids can reduce inflammation and help dampen immune system activity. Additionally, pain relief medications — such as acetaminophen and ibuprofen — can help with muscle pain.

If these treatments are not effective, plasma exchange therapy or intravenous immunoglobulin (IVIG) may help. IVIG contains antibodies from healthy donors that bind to the autoantibodies that are causing inflammation, helping remove them from circulation.

ADEM

Corticosteroids generally help individuals with ADEM recover. In severe situations, plasma exchange therapy or IVIG may help.

ALD and AMN

Treating ALD and AMN focuses on addressing individual symptoms and improving quality of life.

Doctors typically use steroid replacement therapy to help address adrenal gland dysfunction. They may also recommend physical therapy to help with movement and muscle strength.

GBS

Healthcare professionals often treat GBS using plasma exchange therapy or IVIG. Some people may recover in as little as a few weeks. However, for others, recovery may take several years, and there may be permanent nerve damage.

CMT

The treatment for CMT focuses heavily on physical and occupational therapy. These interventions can help people with CMT maintain flexibility, muscle strength, and the ability to perform daily tasks.

In some situations, surgery may be necessary to treat foot irregularities. If peripheral neuropathy is present, a person can take pain relief medications.

When demyelination occurs, new myelin can form. However, the new myelin may not be as protective as the old myelin, which means that the transmission of electrical impulses may not be as efficient as before. Stem cell therapy may one day provide a technique to regenerate healthy new myelin.

There are currently no cures available for demyelinating diseases. The overall outlook depends on the specific type of demyelinating disease a person has and the severity of their symptoms.

Treatment can help people manage the symptoms of demyelination. A person’s healthcare team will work with them and their loved ones to help them manage the symptoms and improve their quality of life.