Autoimmune diseases are those in which the body itself attacks itself. One of the best known is multiple sclerosis. In this article, however, we will talk about another one, which is related to it: Devic’s disease or neuromyelitis optica (NMO)
This disease is inflammatory and demyelinating; It affects the nerve fibers of the Central Nervous System, especially those of the optic nerve and the spinal cord. In this article we will learn what it consists of, its fundamental characteristics, its symptoms, causes and treatment.
Devic disease, also called neuromyelitis optica (NMO) (or NMO spectrum of disorders), is a neurological disorder considered rare, affecting between 1 and 9 people in every 100,000. Is about an autoimmune and demyelinating inflammatory disease, which mainly affects the myelin of the optic nerve and the spinal cord
Myelin is a layer that protects the axons of nerve cells, and has the function of increasing the speed of nerve impulse transmission.
Characteristics
The main affectation in Devic’s disease is a demyelination of the nerve fibers of the Central Nervous System (CNS), which includes the optic nerve (it becomes inflamed) and which produces axonal degeneration. On the other hand, spinal symptoms also appear due to inflammation of the spinal cord (motor and sensory alterations in the extremities).
In relation to its course, it can vary from one person to another; In women, for example, there is usually a course of recurrent attacks. However, although more rarely, a monophasic course can also occur, with episodes of optic neuritis (ON) (inflammation of the optic nerve) and myelitis isolated in time, but simultaneous (later we will see what they consist of).
This second type of course It appears more typically in young people, both in men and women Regarding its distribution by sex, 90% of people affected by Devic disease are women. The average age of onset is around 50-55 years, although it can appear at any age.
Symptoms
The main symptoms of Devic’s disease are the following:
1. Optic neuritis (ON) attacks
Optic neuritis is an inflammation of the optic nerve. These attacks can be unilateral or bilateral. Basically, in these episodes The cells of our immune system attack the structures of the body; in this case, to the myelin sheaths of the optic nerve(s). This symptom is also typical of multiple sclerosis.
2. Acute myelitis
Also called acute transverse myelitis, it is an inflammation of the white and gray matter of the CNS, in one or more adjacent spinal cord segments. Generally the chest segments become inflamed. Myelitis can appear due to Devic’s disease, but also due to multiple sclerosis, infections, certain drugs, etc
3. Attacks of blindness
These attacks are usually acute and very serious. It is common for them to appear separated in time (every “X” months or even years). After them, the patient shows a partial recovery thereof.
Attacks of blindness generally appear simultaneously with attacks of optic neuritis and myelitis.
4. Paraparesis or quadriparesis
Paraparesis involves reduced motor strength in two of the limbs (generally the lower ones); It can also cause paralysis in them. Quadriparesis is the same but with involvement of all four limbs.
The senses of the patient with Devic’s disease may deteriorate as the disease progresses, due to the different attacks that occur. This will imply difficulties or alterations in your visual and auditory system, mainly.
6. Deterioration of the sphincters
The sphincters, as they depend on the spinal cord and, therefore, the CNS, will also be affected in this disease. This can cause, for example, urine leakage due to weakening and loss of sphincter control
7. Other symptoms
Devic disease can also involve other symptoms, although they are rarer. These can be vomiting, nausea (caused by inflammation of the spinal cord), sleep or endocrine disorders (caused by a disturbance in the hypothalamus) and attacks of cerebral edema. The latter can cause some confusion in the patient, even inducing a coma.
8. Associated disorders
It is common for people who suffer from Devic’s disease to also manifest other types of disorders, these being systemic and autoimmune. Examples of them are: Sjögren’s syndrome and systemic lupus erythematosus (SLE)
Causes
The cause of Devic’s illness is unknown. However, its etiology has been related to autoantibodies against aquaporin-4 (a type of antibody). That is to say, It is known to have an autoimmune origin, like multiple sclerosis
As there is still no well-defined and easy-to-determine cause of this disease, Its diagnosis is basically clinical, made from the observation of the symptoms manifested by the patient On the other hand, although the diagnosis is mostly clinical, MRI (Nuclear Magnetic Resonance) tests are normally performed to detect possible spinal lesions.
In acute attacks of myelitis, spinal lesions typically involve 3 or more vertebral segments. This technique (MRI) can be used to differentiate Devic’s disease from other autoimmune disorders, such as Multiple Sclerosis (MS). A difference between these pathologies, and which also helps to establish a diagnosis, is a normal brain MRI in the early stages of Devic disease
Sometimes it happens, however, that the patient has had atypical brain lesions, or has only had a first episode of myelitis; In these cases, finding autoantibodies against aquaporin-4 helps diagnose Devic disease with a little more certainty.
Treatment
Drug treatment used for Devic disease includes intravenous corticosteroids ; These drugs usually reduce the duration of the symptoms that cause attacks of blindness and optic neuritis. In addition, they have the advantage that they accelerate the patient’s visual recovery.
However, the use of corticosteroids has no influence on the patient’s functional recovery or prognosis. It also does not reduce the risk of developing multiple sclerosis in the future (since these two diseases are closely related).
Prevention of Devic disease is very important, and any slightest symptom should be taken into account. A good preventive strategy is to perform a brain magnetic resonance imaging (MRI) if you suspect you may have the disease. On the other hand, once the disease is diagnosed, it will be of great importance go to specialized ophthalmologists and neurologists who can recommend an appropriate treatment for each case.
Forecast
Devic’s disease has a good prognosis, although sometimes certain visual disturbances may remain. In more severe cases, the patient may go blind
