Demyelination occurs when myelin, which is the protective coating of nerve cells, experiences damage. When this happens, neurological problems can occur.
It can result from various medical conditions, including multiple sclerosis (MS).
In this article, we take a look at some diseases that cause demyelination, the symptoms that may develop, and the treatment options for each.
Many of the fibers in the nervous system have a coating — or sheath — of myelin, a fatty white substance. These myelin sheaths enable electrical impulses to pass along the nerve cells quickly and efficiently.
How well impulses travel determines how smoothly and quickly a person can perform everyday movements.
Some diseases result in damage to the myelin sheaths, which may cause problems in the brain, eyes, spinal cord, and other parts of the body. Doctors call these conditions "demyelinating diseases." They include MS.
Demyelinating diseases can affect a wide range of body functions.
Vision: It can lead to blurred 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. It can affect movement, and it can make it hard for a person to speak and swallow. It rarely affects unconscious actions, such as breathing and blood pressure.
Senses and feeling: A person may experience numbness, 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 if 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 tremor or incoordination. Some people may find that swallowing, writing, eating, and walking become difficult.
Genitourinary system: Some people may experience problems with urination and bowel movements. It can impact sexual health, making it harder for a man to have an erection or a woman to have an orgasm. Some people may feel pain during sex, and they may have a higher chance of developing a urinary tract infection.
A person may also experience constant fatigue without any particular cause.
There are many different types of demyelinating disease. Below is a list of some of these conditions, along with information on possible treatment options.
The most common type of demyelinating disease is MS. It happens when the immune system mistakenly attacks and damages myelin.
The term multiple sclerosis means "many scars." Damage to myelin in the brain and spinal cord can result in hardened scars that can appear at different times and in different places. These can lead to various symptoms of demyelination.
Common symptoms include pain, numbness, and tingling.
However, neurological changes can affect a wide range of body functions, including vision, mood, the ability to think, and bladder and bowel control.
For some people, the symptoms will remain mild, but for others, they can become severe.
Most people will experience times of relapse when symptoms worsen for a while, and remission, when symptoms may disappear altogether.
There is currently no cure for MS, but scientists have made significant progress in recent years, and 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 these disease-modifying therapies (DMTs) from the earliest possible stage when it appears to be most effective. A DMT for MS will 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 can treat specific symptoms, including antidepressants and pain relief medication.
MS usually starts between the ages of 20–40 years, and it affects twice as many women as men. Most people with a diagnosis of MS will have the same life expectancy as people without MS.
MS is one cause of optic neuritis, which involves a swelling of the optic nerve, leading to changes in vision and eye pain.
Corticosteroids can help reduce inflammation.
Learn more here about optic neuritis.
Neuromyelitis optica, or Devic's disease, occurs when the immune system attacks and destroys myelin, resulting in:
- optic neuritis
- pain, weakness, or both in the spine and limbs
- bladder and bowel problems
If neuromyelitis optica affects breathing, it can be life-threatening.
Corticosteroids can treat symptoms, and drugs that reduce the activity of the immune system may help prevent future attacks.
Find out more about neuromyelitis optica.
Transverse myelitis is an inflammation of the spinal cord. It affects sensation.
It can cause:
- pain and weakness in the limbs
- bladder and bowel problems
Corticosteroids can reduce inflammation. Pain relief medications, such as acetaminophen, can help with muscle pain. If these are not effective, plasma exchange therapy may help.
Acute disseminated encephalomyelitis
Acute disseminated encephalomyelitis (ADEM) causes inflammation in the brain and spinal cord. This can damage myelin and can lead to fever, exhaustion, headache, nausea, vomiting, and sometimes seizures. It can be life-threatening.
Corticosteroids or plasma exchange therapy may help.
There are currently no cures available for demyelinating diseases, but treatment can help people manage symptoms.
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 is not as efficient as before.
Stem cell therapy may one day provide a technique to regenerate healthy new myelin.