Autoimmune diseases are those in which the body 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 optic (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 know what it is, its basic features, symptoms, causes and treatment.
What is Devic’s disease?
Devic’s disease, also called neuromyelitis optic (NMO) (or spectrum of NMO disorders), is a neurological disorder considered rare, affecting between 1 and 9 in 100,000 people. It is an inflammatory autoimmune demyelinating disease, which primarily affects the myelin of the optic nerve and spinal cord.
Myelin is a layer that protects the axons of nerve cells and has the function of increasing the speed of transmission of nerve impulses.
The main implication in Devic’s disease is demyelination of nerve fibers in the central nervous system (CNS), which includes the optic nerve (this becomes inflamed) and causes axonal degeneration. On another side, more spinal cord symptoms appear due to the inflammation of the spinal cord (Motor and sensory alterations of the limbs).
Depending on its course, it may vary from one person to another; in women, for example, a course of recurrent attacks is usually administered. However, although more rarely, a single-phase course can also occur, with episodes of optic neuritis (ON) (inflammation of the optic nerve) and myelitis isolated over time, but simultaneous (we will see later what is ).
This second type of course it appears more generally in young people, men and women. As for its distribution by sex, 90% of people affected by Devic’s disease are women. The average age of onset is around 50 to 55 years old, although it can appear at any age.
The main symptoms of Devic’s disease are as follows:
1. Attacks of optic neuritis (ON)
Optic neuritis is 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, in 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. The segments of the chest are usually inflamed. Myelitis can appear due to Devic’s disease, but also due to multiple sclerosis, infections, certain medications, etc.
3. Attacks of blindness
These attacks are usually acute and very severe. They usually appear separately over time (every “X” months or even years). After them, the patient exhibits partial recovery of the same.
Attacks of blindness usually occur at the same time as attacks of optic neuritis and myelitis.
4. Paraparesis or quadriparesis
Paraparesis involves reduction of the motive force of two of the limbs (Usually the lowest); it can also cause them paralysis. Quadriparesis is the same but with involvement of all four limbs.
5. Significant disability
The senses of the patient with Devic’s disease may deteriorate as the disease progresses, due to the various attacks produced. This will mainly involve difficulties or alterations in your visual and hearing system.
6. Deterioration of sphincters
The sphincters, as they depend on the spinal cord and therefore the CNS, will also be affected in this disease. This can lead, for example, to loss of urine due to weakening and loss of control of the sphincter..
7. Other symptoms
Devic’s disease can involve other symptoms as well, although they are rarer. These can be vomiting, nausea (caused by inflammation of the spinal cord), sleep or endocrine disturbances (caused by an alteration in the hypothalamus), and attacks of brain edema. The latter can cause confusion in the patient, or even induce a coma.
8. Associated disorders
It is common for people with Devic’s disease to have other types of disorders as well, these being systemic and autoimmune. Examples of these are: ed Sjögren syndrome and systemic lupus erythematosus (SLE).
The cause of Devic’s disease is unknown. However, its etiology has been linked to autoantibodies against aquaporin-4 (a type of antibody). In other words, that is to say it is known to have an autoimmune origin, just like multiple sclerosis.
As there is not yet a well-defined and easily determined cause in this disease, its diagnosis is essentially clinical, made from the observation of the symptoms manifested by the patient. On the other hand, although the diagnosis is mainly clinical, NMR (Nuclear Magnetic Resonance Imaging) tests are usually performed to detect possible damage to the spinal cord.
In acute myelitis attacks, lesions to the spinal cord typically cover 3 or more vertebral segments. This technique (MRI) can be used to differentiate Devic disease from other autoimmune diseases, such as multiple sclerosis (MS). A difference between these pathologies, and the one which also helps to establish a diagnosis, is 1 Normal brain MRI in the early stages of Devic’s disease.
Sometimes, however, the patient may have had atypical brain damage or only had a first episode of myelitis; in these cases, finding autoantibodies against aquaporin-4 helps diagnose Devic’s disease with a little more certainty.
Pharmacological treatment used for Devic’s disease includes intravenous corticosteroids; these drugs usually decrease the duration of symptoms that cause episodes of blindness and optic neuritis. In addition, they have the advantage of accelerating the visual recovery of the patient.
However, the use of corticosteroids has no influence on the functional recovery or the prognosis of the patient. It also does not decrease the risk of developing multiple sclerosis in the future (since these two conditions are closely related).
Prevention of Devic’s disease is very important and any minimal symptoms should be considered. A good preventative strategy is to perform magnetic resonance imaging (MRI) of the brain in the face of any suspicion of suffering from the disease. On the other hand, once the disease is diagnosed, it will be of great importance go to specialist ophthalmologists and neurologists who can recommend appropriate treatment in each case.
Devic’s disease has a good prognosis, although some visual disturbances can sometimes remain. In more severe cases the patient may go blind.
- Alvarez, JC et al. (2014). Multiple sclerosis monographs. Demyelinating diseases with optic and medullary involvement in MS: 9-96.
- Arias-González, NP, Valencia-Parets, D. (2014). Optic neuromyelitis, anti-aquaporin antibody 4. Medical Journal MD, 6 (1): 58-61.
- Wingerchuk, D., Lennon, V., Lucchinetti, C., Pittock, S. and Weinshenker, B. (2007). The spectrum of optic neuromyelitis. The Lancet Neurology, 6: 805-815.