Demyelinating diseases, such as multiple sclerosis (MS), involve damage to myelin, the protective coating of nerve cells. Depending on the disease, they can lead to weakness, vision loss, and other neurological symptoms.
The medical term for the damage of myelin is demyelination.
This article looks at some conditions that cause demyelinating disease, 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, 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 is one of the factors that 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 damage the myelin sheath, which can cause problems in the brain, the eyes, the spinal cord, and other nerves in 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, spinal cord, and optic nerves. Experts do not know the exact cause of MS. However, they do believe that genetic and environmental factors play a role.
Demyelination can lead to a wide range of neurological symptoms during MS exacerbations. In severe cases, damage to myelin can lead to hardened scars that are permanent and cause lasting symptoms.
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
Some MS variants can worsen with time. For example, Schilder’s disease is a progressive variant of MS that most commonly starts in childhood. The disease causes widespread demyelination through the brain and spinal cord. The condition is very rare, and the underlying causes are not clear.
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 visual 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.
The condition is a common part of MS and occurs in around
Inflammatory diseases, such as lupus, can cause the condition. It is also common in people with viral infections, such as mumps, measles, and the flu.
Neuromyelitis optica
Neuromyelitis optica (NMO), or Devic’s disease, occurs when the immune system attacks and destroys myelin in the spinal cord and eye. NMO can affect one or both sides of the spinal cord and eyes.
This can result in symptoms and complications such as:
- vision loss from optic neuritis
- weakness, pain, or both in the limbs
- bladder and bowel problems
Many people with neuromyelitis optica have episodes of symptoms that can occur months or years apart.
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 affecting both sides of the spinal cord at the same level. 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:
- MS
- neuromyelitis optica
- certain infections, such as varicella-zoster, syphilis, or tuberculosis
- autoimmune conditions, such as lupus or Sjögren’s
Although transverse myelitis can affect people of any age, it
Acute disseminated encephalomyelitis
Acute disseminated encephalomyelitis (ADEM) occurs
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.
Adrenoleukodystrophy and adrenomyeloneuropathy
Adrenoleukodystrophy (ALD) is a genetic condition that leads to myelin damage. It has an estimated prevalence of
- adrenal gland dysfunction (Addison’s disease)
- vision or hearing loss
- impaired coordination and movement
- changes in behavior, such as withdrawal or aggression
- problems with memory and learning
- difficulty with speech
- swallowing difficulties
- seizures
Adrenomyeloneuropathy (AMN) occurs in adults with the same mutation that causes ALD. It is often milder, begins between the ages of
- 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 myelin. In severe cases, it can also attack the nerves of the peripheral nervous system. This only occurs if inflammation continues after it destroys the myelin.
People may also refer to GBS as acute demyelinating polyneuropathy.
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. If this paralysis affects muscles that control breathing, respiratory support will be necessary during treatment.
Certain infections are known to trigger GBS. One of the most common triggers is an infection with Campylobacter jejuni, which causes food poisoning. Experts believe that up to
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
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 daily tasks.
HTLV-I-associated myelopathy (HAM)
The HTLV-I virus can cause slow, progressive myelopathy. Myelopathy means damage to the spinal cord.
HAM causes demyelination in the spine, leading to symptoms.
Symptoms of HAM are similar to those of primary progressive multiple sclerosis (PPMS). However, most people who have HTLV-1 infection do not develop myelopathy.
Demyelinating diseases can affect many areas of the nervous system, 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 toward their chest, 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.
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 excessive exertion or lack of sleep.
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. However, 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 one of several disease-modifying therapies (DMT) starting at diagnosis because early treatment can help improve long-term outcomes. DMT for MS helps reduce excessive immune system activity.
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 and problems with coordination and balance.
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 short-term treatment for acute flare-ups.
Neuromyelitis optica
Corticosteroids and plasma exchanges can treat the symptoms of acute attacks.
In plasma exchange therapy, blood flows from a venous catheter into a machine that removes the antibodies and places the blood back into the body through a venous catheter.
Conversely, drugs that reduce the activity of the immune system — such as methotrexate and azathioprine — are beneficial as maintenance therapies and may help prevent future episodes.
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 ineffective, plasma exchange therapy or intravenous immunoglobulin (IVIG) are potential short-term treatments for acute episodes. IVIG contains antibodies from healthy donors that bind to the autoantibodies 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
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.
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.