The Optic neuromyelitis (NMO), also known as Devic's disease, is a pathology of autoimmune origin, Inflammatory and demyelinating factors that primarily affect the spinal and optic nerve terminals (Chiquete et al., 2010).
At the clinical level, this disorder is characterized by the presentation of alterations related to optic neuritis and spinal myelitis. Signs and symptoms may range from major neurological involvement, severe blindness or even the death of the affected person (Álvarez Pinzón, 2012).
In addition, optic neuromyelitis usually follows a course in the form of relapses or recurrent outbreaks, in which the symptoms usually present acutely And severe (Álvarez Pinzón, 2012).
In the case of diagnosis, this is usually done based on three clinical conditions ( Optic neuritis , Acute myelitis And absence of related symptoms With the CNS) and the use of various laboratory tests ( Magnetic resonance , Analysis of cerebrospinal fluid, Serological examination , Potential Evoked, etc.) (Alemán-Iñíguez, Alemán-Iñíguez and Díaz Heredia, 2015).
Because it is a rare disease, there is currently little information on specialized treatments for optic neuromyelitis. Usually, interventions usually focus on symptom control and recurrence of outbreaks (Chiquete et al., 2010).
The most common treatments include administration of Corticosteroids , Immunosuppressants , the Plasmapheresis Or physical therapy and rehabilitation (National Institute of Neurological Disorders and Stroke, 2016).
Characteristics of Optic Neuromyelitis
Optic neuromyelitis or Devic's disease is a pathology of the nervous system that affects the optic nerves (optic neuritis) and the Spinal (myelitis) (Mayo Clinic, 2015).
In addition, optic neuromyelitis is an autoimmune disease, that is, our body's immune system reacts against its own cells Resulting in a demyelinating process (Mayo Clinic, 2015).
The cells and nerve terminals of our body are responsible for receiving and generating messages consistently, from the different body areas To centers of the central nervous system that are responsible for developing and processing responses to environmental demands (HealthLine, 2016).
Thus, a good part of our nervous structure, is covered with myelin, that is to say, a membrane or protective layer that contains large Quantities of Lipids , To isolate axons from nerve cells and prevent them from being damaged by the extracellular environment (Clarck et al., 2010).
In particular, the Myelin Is key in the rapid transmission of nerve signals, so it is essential for the functioning of our Central and peripheral nervous system is efficient (National Institutes of Health, 2016).
Thus, in some pathologies such as optic neuromyelitis, the presence of an abnormal immune process will cause damage to the myelin, Destroying it in whole or in part (HealthLine, 2016).
As a consequence of a demilinating process, a Axonal damage , Slowing the flow of nervous information and causing serious damage Structural and, therefore, deficits related to the motor, sensory or cognitive sphere (HealthLine, 2016).
Thus, optic neuromyelitis was described in the last years of the 19th century, by Albut, as an autonomic disorder of the eyes, Triggers in several acute episodes of paraplegia (Álvarez Pinzón, 2012).
However, it is not until 1894 that researchers Eugène Devic and Fernand Gault, on a clinical level, characterize the course of optic neuromyelitis.
In His clinical report describes a total of 17 cases (Chiquete et al., 2010), in which a significant association between various lesions Located in the optic and spinal nerves (Álvarez Pinzón, 2012).
In addition, for many years, optic neuromyelitis has been characterized in the medical literature as a variant of multiple sclerosis , Although in the Today, thanks to modern research techniques, a wide variety of differential clinical and laboratory findings have been found (Carnero Contentti, Leguizamón, Colla Machado and Alonso, 2013).
On the other hand, we must take into account that optic neuromyelitis may be referenced with other types of denominations, which include: Multiple sclerosis optic-esinal or Asian; Devic's disease, Devic's syndrome, opticomyelitis or optic neuromyelitis (National Organization for Rare Disorders, 2015).
Is it a frequent pathology?
Optic neuromyelitis is a rare disease in the general population. Its prevalence is estimated at around 1-5 cases per 100,000 people in (National Organization for Rare Disorders, 2016).
In the case of the United States, several health organizations have indicated that there may be approximately 4,000 people affected by Optic neuromyelitis and about 250,000 worldwide (National Multiple Sclerosis Society, 2016).
In addition, optic neuromyelitis is a pathology that can affect anyone, regardless of gender, age or geographical origin, without However, a differential prevalence has been observed in some cases (National Multiple Sclerosis Society, 2016):
- More than 80% of cases of optic neuromyelitis are diagnosed in women.
- It has been estimated that it is the most frequent Demyelinating disease In Asian, African or Native American populations.
- Although it can occur in any age group, there is a prevalence peak around 40-50 years.
Signs and symptoms
The clinical course of optic neuromyelitis is characterized by the development of recurrent episodes of optic neuritis and myelitis. Generally, these Are sequential and in rare cases, occur simultaneously (Chiquete et al., 2010).
Thus, the course of optic neuromyelitis is defined as monophasic and relapsing, ie characterized by outbreaks and relapses in more than 70% of cases Diagnosed (Álvarez Pinzón, 2012).
We will then describe in detail each of the medical conditions that characterize this pathology (Mayo Clinic, 2015; Organization for Rare Disorders, 2015):
Neuritis Optica
Optic neuritis is a type of pathology that affects the optic nerve Producing a significant inflammation of it.
Usually, this disorder usually occurs unilaterally, that is, it affects one eye, although in other cases it may cause bilateral symptoms.
The clinical course of optic neuritis usually encompasses a wide range of ophthalmic signs and symptoms; however, the most common are related With the presentation of acute eye pain and loss of visual acuity.
In addition, other types of alterations may also occur:
- Edema, paleness or malformation of the optic paw : The optic papilla is an ocular region located in the center of the retina, is a point Through which the optic nerve originates. In the case of optic neuritis, the involvement of the optic nerve can produce various abnormalities in This structure, with inflammation being one of the most significant.
- Discromatopsia : This pathology refers to a total or partial loss of the ability to perceive and distinguish colors. Specifically, depending on the affected wave may appear a protanopia (red color blindness), deuteranopia (green color blindness), tritanopia (Blue color blindness) or acormatosia (total color blindness).
- Afferent pupillary deficit : The pupil is an ocular structure that is in charge of controlling the amount of light that accedes to this one, Specifically, when a demyelinating-like disease affects the retina, optic nerve, optic tract, or optic chiasma , A Asymmetry.
In this case, before the light stimulation, the affected retina shows a pathological response dilating, whereas the normal one is Contract
Transverse myelitis
Transverse myelitis is a pathology that refers to the existence of a pathological and / or abnormal inflammation of the spinal cord .
At the clinical level, it can lead to the development of sensory, motor and autonomic symptoms, normally characteristic of nervous centers Located at a lower level of the location of the spinal cord injury or involvement.
Typically, this disorder usually begins with the initial presentation of pain in the upper and lower extremities or in the back, followed by Loss of sensation or Paresthesia In the lower limbs and a loss of bowel and bladder control.
In addition, during the most severe outbreaks, affected individuals may also have muscle paralysis or paraplegia, significant neck stiffness I Recurrent headaches .
On the other hand, the reach of a good part of the spinal structures and / or brainstem may lead to the development of other types of symptoms Neurological disorders of greater severity, such as seizures or epileptogenic episodes.
Apart from the characteristics of optic neuritis and transverse myelitis, in the majority of cases, the initial symptoms related to Loss of sensation or the development of muscular paralysis, have to improve with therapeutic interventions (National Organization for Rare Disorders, 2015).
However, in cases of recurrent algos of visual or spinal symptoms, they may present permanently, the most common are blindness Or mobility deficits (National Organization for Rare Disorders, 2015).
Causes
Although the specific origin of optic neuromyelitis is not known with complete accuracy, involvement of the optic and spinal nerves seems to be Be associated with the presence of pathological or abnormal antibodies (National Institute of Neurological Disorders and Stroke, 2016).
Specifically, these antibodies bind to a protein called Aquaporin-4 Which, among other things, triggers the activation of various components of the Immune system, leading to damage and inflammation of healthy cells (National Institute of Neurological Disorders and Stroke, 2016).
On the other hand, at the genetic level, more than 95% of cases of optic neuromyelitis occur sporadically, so it is not associated with a history Of this pathology. However, about 3% if there is any history of optic neuromyelitis (National Organization for Rare Disorders, 2015).
Thus, familial cases of this pathology are usually associated with a history of deficiencies and autoimmune disorders (National Organization for Rare Disorders, 2015
Diagnosis
The diagnosis of optic neuromyelitis is based on two fundamental pillars, the clinical findings and the complementary tests of Confirmation (Chiquete et al., 2010).
In this way, the clinical criteria are usually followed (Rodriguez, Gil, Restrepo and Iglesias Gamarra, 2011):
A. Basic Criteria:
- Optic Neuritis
- Acute Myelitis
B. Supplementary or Supporting Criteria:
- Brain magnetic resonance: absence of structural brain lesions characteristic of Multiple Sclerosis.
- Spinal magnetic resonance: absence of spinal cord lesions corresponding to the three segments of the vertebral bodies.
- Antibodies: presence of anti-AQP4 antibodies, ANAS, ENAS or anti-thyroglobulins.
- Cerebrospinal fluid: presence of white cells or alterations related to bacterial meningitis.
- Electro-diagnostic analysis: subclinical lesions identified through the analysis of the evoked potentials.
Treatment
There is currently no curative treatment for optic neuromyelitis, however, various therapeutic interventions have been designed for the Treatment of symptomatic outbreaks, medical complications, and relapse prevention.
In the case of acute episodes of symptoms, the administration of Corticosteroids wave Plasmapheresis (Eliminating harmful antibodies from the Blood circulation) are the most common treatments of choice (National Institute of Neurological Disorders and Stroke, 2016).
In the case of corticosteroids, these are usually given in high intravenous doses, whereas plasmapheresis involves mechanical separation Of blood plasma and its replacement by an organic solution (National Organization for Rare Disorders, 2015).
On the other hand, in the preventive intervention of the symptomatic outbreaks, the administration of drugs Immunosuppressants Such as mycophenolate, mofetil, Rituximab and aztioprima, are usually effective (National Institute of Neurological Disorders and Stroke, 2016).
In addition, for the relief and improvement of other complications such as spasms and muscle stiffness, ocular or muscular pain, or intentional and (National Institute of Neurological Disorders and Stroke, 2016).
Similarly, in the most severe cases, where there is a significant physical disability accompanied by functional dependence, the use of Therapy and physical rehabilitation.
Forecast
The medical perspectives of people with this type of pathology are often worse than those expected from the development of Multiple sclerosis (Chiquete, 2010).
About 60% of people diagnosed, usually present symptomatic relapses during the first year and 90% during the first three years (Chiquete, 2010).
At symptomatic level, almost half of patients after 5 years of clinical course usually present partial or total blindness in one or both eyes. In addition, many of the deaths are associated with a respiratory failure of neurological origin (Chiquete, 2010).
References
- German-Iñiguez, J., Alemán-Iñiguez, V., & Díaz-Heredia, F. (2015). Management of relapse in Devic's disease. First successful treatment, reported with Plasmapheresis in Ecuador; Bibliographic review, news and case report. . Rev. Mex. Oftalmol, 63-69.
- Page 2 Neuromyelitis Optica. Pathology, Diagnosis and Treatment in the 20th Century. Rev Sal Bosq, 2 (1), 35-45.
- Carnero Contentti, E., Leguizamón, F., Colla Machado, P., & Alonso, R. (2013). Optic neuromyelitis: clinical and therapeutic update. Neurol Arg, 259-269.
- Chiquete, E., Navarro-Bonnet, J., Ayala-Armas, R., Gutiérrez-Gutiérrez, N., Solórzano-Meléndez, A., Rodríguez-Tapia, D.,. . . Ruiz-Sandoval, J. (2010).
Optic neuromyelitis: clinical update. Rev Neurol, 51 (5), 189-294. - Cleveland Clinic. (2016). Devic's Disease (neuromyelitis). Obtained from Cleveland Clinic.
- Mayo Clinic. (2015). Neuromyelitis Optica. Obtained from Mayo Clinic.
- NIH. (2016). National Institute of Neurological Disorders and Stroke. Obtained from Optic Neuromyelitis.
- NMSS. (2016). Neuromyelitis Optica (NMO). Retrieved from the National Multiple Sclerosis Society.
- NORD. (2015). Neuromyelitis Optica. Retrieved from the National Organization for Rare Disorders.