Demyelination occurs when the protective layer of nerve cells, known as myelin, is damaged.
When this happens, neurological problems may occur.
Demyelinating diseases damage the linings of nerve cells.
Many of the nerve fibers in the nervous system are covered with a white, fatty substance called myelin. These myelin sheaths allow electrical impulses to be transmitted along with nerve cells quickly and efficiently.
How well these impulses are conducted determines how smoothly and quickly a person can perform daily movements with little conscious effort.
Symptoms of demyelinating diseases
In general, demyelinating diseases can affect:
- Reflections and movement.
- The senses.
People who experience these symptoms may also experience persistent exhaustion that does not seem to have a particular cause.
People with a demyelinating disease may experience blurred vision, loss of vision, double vision, or feel their vision swing back and forth.
Some people may also experience weakness in their extremities and the trunk of their body or have trouble balancing. In addition, muscles can contract, causing stiffness or tightness and interfering with movement and speech.
People may also experience spikes in blood pressure and rapid heartbeat due to a nervous system that overreacts.
Some people may experience numbness, burning, or tingling in their arms, legs, or feet. They may also feel pain when touched lightly.
Some people with demyelinating diseases, such as multiple sclerosis (MS), get a symptom called Lhermitte’s sign. This feels like an electric shock that goes through the back of the neck to the spine and then through the arms and legs.
Symptoms related to the brain:
Demyelinating diseases can cause memory problems, difficulty concentrating, and cognition problems.
People with a demyelinating disease may also experience tremors or incoordination. Sometimes, swallowing, writing, eating, and walking can be difficult.
Symptoms that affect the genitourinary system:
Demyelinating diseases can affect how someone needs to use the bathroom. These conditions can cause people to have incontinence (where they can not control their bladder or bowels) or constipation (where they can not empty their bowels wholly and regularly).
Urinary tract infections may also be more common in people with demyelinating diseases.
The sexual health of people with demyelinating diseases can be affected. Men may be unable to have an erection, and both women and men may be unable to achieve orgasm. People with demyelinating disorders can also experience pain during sex.
There are many different types of demyelinating diseases. The diagnosis varies from one disorder to another.
The term multiple sclerosis means “many scars.” It refers to areas of the brain and spinal cord where myelin has been lost, leaving hardened scars that may appear at different times and in other places.
Unfortunately, there is no cure for MS, but many of the symptoms can be treated.
There are medications available to treat MS relapses and control symptoms, usually taken orally or by injection.
MS is more common among women than among men. Approximately three women and two men suffer from this particular demyelinating disease.
Although MS is not hereditary, some doctors believe that genes can make some people more susceptible to the disease than others.
Optic neuritis is another demyelinating disease that can arise from multiple sclerosis.
This condition is more common among people between 20 and 40 years old. Its most common symptoms are pain with eye movement, vision loss, or loss of sight of colors.
Optic neuritis is often treated with corticosteroids, although if doctors suspect that MS is causing the problem, they can prescribe medication for MS.
Optic neuromyelitis, or Devic’s disease, occurs when the immune system attacks and destroys myelin, causing pain in the spine and extremities and causing problems in the bladder and bowel.
Optic neuromyelitis can sometimes cause death if a person’s breathing is affected. The initial attack of optic neuromyelitis is likely to be treated with corticosteroids. Medicines that suppress the immune system, called immunosuppressants, can be used to prevent further attacks.
Transverse myelitis is an inflammation of the spinal cord. This type of demyelinating disease affects sensitivity and can cause pain and weakness in the arms and legs, as well as causing problems in the bladder and bowel. About 1,400 new cases of transverse myelitis are diagnosed each year in the United States.
Like other demyelinating diseases, corticosteroids can be prescribed to reduce inflammation of the spine.
Doctors may recommend plasma exchange therapy for people who do not respond to corticosteroids. This procedure replaces the plasma (the fluid in which blood cells and antibodies travel) with special liquids.
Analgesics such as acetaminophen, ibuprofen, and naproxen may also help with muscle pain.
Acute disseminated encephalomyelitis:
Acute disseminated encephalomyelitis (ADEM) is a widespread attack of inflammation in the brain and spinal cord. Inflammation damages the myelin and can cause fever, exhaustion, headache, nausea, and vomiting.
In some severe cases, people may experience seizures, go into a coma or die. A small fraction of people with this condition develops MS.
Like transverse myelitis, corticosteroids or plasma exchange therapy can be considered to reduce inflammation caused by ADEM.
Adrenoleukodystrophy and adrenomyeloneuropathy:
Adrenoleukodystrophy and adrenomyeloneuropathy are inherited and rare demyelinating diseases caused by a genetic mutation that usually only affects men. However, some women may carry the gene, and, in some cases, women may develop symptoms.
The symptoms of these conditions vary and cover the full range of symptoms of demyelinating disease described above.
If people with adrenoleukodystrophy or adrenomyeloneuropathy have low adrenaline and cortisol levels, then a doctor can prescribe steroids, which can replace hormones and improve a person’s quality of life.
Other treatments for these conditions are currently in clinical trials.
Currently, there are no cures available for demyelinating diseases. As a result, treatment tends to focus on reducing and managing symptoms and slowing the progression of the disease.
When demyelination occurs, new myelin can grow. However, the new myelin is not as solid and protective as the old myelin, which means that the transmission of electrical impulses is not as efficient as before.
Researchers are studying what can be done to improve how the body produces new myelin.