The Optical neurourits (NO) is a pathology in which a slight or significant inflammation of the optic nerve occurs (Ernene et al., 2016).
At the clinical level, the functional and structural alteration of this nervous branch is characterized by the presence or development of a deficit of acuity and Visual ability, chromatic ability, afferent pupillary alteration and, in some cases, accompanied by edema, atrophy or pallor of the nerve (Buompadre, 2013).
In addition, the clinical course of optic neuritis tends to be highly variable, from sudden / progressive to unilateral / bilateral. Furthermore, at an etiological level, Optic neuritis may be caused by demilinating, vascular, toxic, traumatic factors, among others (Bidot, Vignal-Clemont, 2013).
In the case of the diagnosis of this type of pathologies, the physical, ophthalmologic and neurological examination is fundamental, complemented with diverse Such as magnetic resonance, campimetry, or evoked potentials (Gutiérrez-Ortiz and Teus Guezala, 2010).
The treatment of optic neuritis usually focuses on the control or elimination of the identified ethological cause and, on the other hand, the reduction and Severity of the episodes or symptomatic attacks, generally through the administration of corticoids and immunomudulators (Buompadre, 2013).
Characteristics of optic neuritis
Optic neuritis is the medical term commonly used to refer to the presence of inflammation of the optic nerve (Mayo Clinic, 2014).
The optic nerve, also called the cranial nerve II, is the nervous branch responsible for the transmission of visual information, that is, the stimuli that Are generated in the retina And are transferred to the occipital area of the cerebral cortex for processing (Buompadre, 2013).
Thus, the function of the cranial pair II is fundamentally sensory, encompassing the peripheral receptors of the retina, the central pathways and the centers Cortical (Sánchez Méndez, 2016).
In this way, when there is a temporary affectation or permanent lesion of the optic nerve, a wide variety of ophthalmological symptoms (Gutierrez-Ortiz and Teus Guezala, 2010).
The pathologies and medical events that most frequently affect the optic nerve are glaucomas (altered intraocular pressure) and pathologies Inflammatory, comprehensive or inflammatory, hereditary and traumatic (Gutierrez-Ortíz and Teus Guezala, 2010).
Specifically, optic neuritis can cause a wide pattern of visual loss, localized pain, and other neuro-ocular symptoms (Mayo Clinic, 2014).
Although optic neuritis is a pathology that is usually associated with multiple sclerosis , Usually constituting one of its Symptoms, in other cases, it is an isolated medical event that usually occurs after the administration of an early and efficient treatment (May Clinic, 2014).
About us
Although there are few epidemiological studies on the global prevalence of optic neuritis, some studies in Sweden and Denmark, indicates that it ranges from 4 to 5 cases of new diagnosis, per 100,000 individuals in the general population (Ernene et al., 2016).
In addition, various risk factors associated with age, sex, race, or genetic disorders have also been identified (Mayo Clinic, 2014).
Specifically, there is a peak frequency between the ages of 20 and 40. In addition, within these, women often suffer from optic neuritis in A higher proportion than men, with a ratio of 3: 1 (Mayo Clinic, 2014). In addition, optic neuritis has to affect with a frequency greater than The Caucasian individuals (Ernene et al., 2016).
The most common diagnostic situation is the following: a young patient between the ages of 20 and 45, with a first acute event of signs and symptoms related to Ophthalmologic involvement (Ernene et al., 2016).
However, some more atypical cases may also be observed during childhood or in advanced age during old age (Ernene et al., 2016).
Common signs and symptoms
Depending on the etiologic cause and the individual characteristics of the affected person, the symptoms produced by optic neuritis may vary from However, the most common ones include (Buompadre, 2013, Krause, 2015, Mayo Clinic, 2014, Sánchez Méndez, 2016):
to) Episodes of Acute Pain
Many people with optic neuritis report localized pain episodes in the eye areas, especially Behind or around the eyes, periocular pain.
In addition, the feelings of discomfort and pain are often aggravated or accentuated by the movement of the eyes. In many cases, it may be accompanied by Perception of light flashes (photopsies), black spots, and even flashing or flashing lights.
B) Visual Acuity Deficit
The loss of visual acuity is one of the early and cardinal signs of optic neuritis. Generally, it usually appears on a continuum that varies From blurred vision to total absence of light perception.
Typically, these types of symptoms usually occur unilaterally, that is, it affects a single eye, although in approximately 40% of cases Neuritis optica infantile, it courses with a bilateral fall of the visual acuity, simultaneously or consecutively.
In addition, progressive loss of acuity is usually accompanied by altered color perception (discromatopsia) and a significant reduction Of the visual field. In most affected people, these types of symptoms begin with an abnormal or less strange perception of colors.
Usually, this loss of vision is usually temporary, restricted to an exacerbation or symptomatic outbreak, although the duration of the Episode is variable, usually have to be resolved in a period of hours to days. However, in other cases the loss of vision, partial or total, its permanent.
On the other hand, we must take into account that efficient and sharp vision loss, in many cases, can be aggravated by the performance of activity Intense physics or by the presence of elevated temperatures, be they corporal (Uhtholff phenomenon) and / or environmental.
C) Pupillary defect afferent
The pupil is an ocular structure located in the central area of the iris , Usually presents a variable diameter in function of the physical stimuli (Light / dark) or nervous (drugs / fear / surprise, etc.).
The essential function is to control the amount of light that accesses through the eye structure for the correct visual perception, that is, before the Intense lighting in one or both eyes, pupillary constriction usually occurs.
However, in the pathologies that affect this structure, it may appear that there is a defect in the pupillary response to light stimuli.
Thus, in the case of optic neuritis, there is an alteration or afferent transmission of the visual information of the optic nerve, thus, when A source of intense light alternates between both eyes, within an approximate interval of 4 seconds, the affected pupil may respond in the form of dilatation.
(D) Papilloedema
The optic papilla is a blind eye region, in which all the nerve bundles that originate the optic nerve meet. In the case of optic neuritis, Pap smears are frequent, that is, the presence of an inflammation of this area of convergence.
As a result, various symptoms associated with blinking, darkening, blurred or double vision may occur.
Characteristic clinical course
As we have pointed out previously, optic neuritis may have a progressive or sudden course, most usual, is the presentation of a group of symptoms In the form of an outbreak or acute episode (Cleveland Clinic, 2015).
Although the symptoms are variable in different affected individuals, in the case of adults, it is more common that they only affect one eye, Whereas, in the childhood population, optic neuritis usually affects the two eyes more frequently (Cleveland Clinic, 2015).
In addition, the most common is that the crisis tends to be resolved in a short period of time. Normally, the symptoms have to disappear on some days, Approximately one week (Multiple Sclerosis Society, 2016).
However, there are cases in which these become recurrent, causing chronic medical complications, while in others they disappear with a Faster, resolving in hours (Multiple Sclerosis Society, 2016).
Causes
The optic nerve can be affected by a wide variety of factors, inflammatory, infectious, demyelinating, vascular, toxic, Nutritional, hereditary, comprehensive, mechanical and even infiltrative (Buompadre, 2013).
Apart from this, a good part of the optic neuritis is due to the presence of several immunological factors of unknown origin, from Which itself destroys various healthy cells, including myelin that covers the optic nerve branch (Mayo Clinic, 2014).
Myelin is essential for the transmission of information, that is, it allows the electrical impulses to be transmitted quickly and efficiently from the Ocular areas to brain centers are processed (Mayo Clinic, 2014).
When this pathological process appears, the normal process of transmission of disrupted affected visual ability, among other events (Mayo Clinic, 2014).
Specifically, optic neuritis is a very common medical condition in multiple sclerosis. In addition, it has been pointed out that there is a 50% probability Of developing this demyelinating pathology after having suffered one or several episodes of optic neuritis (Mayo Clinic, 2014).
In addition, some research has suggested the presence of some genetic factors related to the predisposition and development of neuritis optics. Specifically, the presence of the haplotype HLA-DR15, DQ6, DW2 has been identified in almost 50% of adult patients diagnosed in addition to Multiple sclerosis (Buompadre, 2013).
Diagnosis
The diagnosis of optic neuritis is clinical, ie the presence and identification of some signs and symptoms, such as afferent pupillary defect, Visual deficit, dyschromatopsia or papillary edema, are sufficient to give the diagnosis (Galdos Iztueta, Noval Martín, Martínez Alday, Pinar Sueiro, Fonollosa Callduch, 2012).
In the phase of physical and ophthalmologic examination, therefore, it is fundamental to explore the sensitivity and visual capacity, the fundus of the eye, the visual field, The integrity of the optic nerve, etc.
In addition, some complementary tests should be used (Galdos Iztueta et al., 2012):
- Magnetic resonance : This type of neuroimaging technique allows the identification of the presence of demyelinating type nerve lesions, Is especially useful for predicting a possible development of multiple sclerosis. Generally, in optic neuritis, Oval, with an amplitude greater than 3 mm and located in periventricular areas.
- Visual evoked potentials : This type of techniques allows to study the potentials generated by the nervous system after the Stimulation of a peripheral sensory organ. Specifically, they are used to examine possible involvement of the optic pathways or to detect lesions Which have not produced obvious clinical symptoms. The most common in optic neuritis is to find an extension of the Latency The P100 wave with a Preservation of the amplitude and morphology of the wave.
- Optical Coherence Tomography : With this technique we can study the thickness of the queen and thus measure its internal thickness and the integrity of The layer of nerve fibers.
Is there treatment?
Due mainly to the demilinating etiologies of optic neuritis, there is no specific cure for this pathology.
Normally, neuritis crises usually recur spontaneously, however, it is recommended to use some therapeutic measures, such as Steroid drugs to control and reduce optic nerve inflammation (Mayo Clinic, 2014).
Although steroids are effective in resolving symptoms, in many cases they have side effects such as stomach disorders, insomnia , Mood changes or increased body weight (Mayo Clinic, 2014).
In addition, steroid therapy is also often used to reduce the risk of developing MS and to accelerate the functional recovery of vision (Mayo Clinic, 2014).
In more severe cases, when other interventions do not show beneficial effects, the Plasmapheresis , However, has not yet been Experimentally confirmed its applications and side effects (Mayo Clinic, 2014).
References
- AAO. (2016). Optic Neuritis . Retrieved from the American Academy of Ophthalmology.
- Bidot, S., & Vignal-Clemont, C. (213). Optical neuropathies. EMC , 1-6.
- Buompadre, M. (2013). Acute optic neuropathy: differential diagnoses. Rev Neurol , 139-147.
- Cleveland Clinic. (2016). Health Information . Obtained from Cleveland Clinic.
- Ergene, E. (2016). Adult Optic Neuritis . Obtained from Medscape.
- Galdos Iztueta, M., Noval Martín, S., Martínez Alday, N., Pinar Sueiro, S., & Fonollosa Callduch, A. (2012). Protocols in optic neuropathy. Part 1. Thea Laboratories Ophthalmologic Research Information Magazine , 1-36.
- Gutiérrez-Ortiz, C., & Teus Guezala, M. (2010). Pathology of the optic nerve. Janus , 59-68.
- Hedges, T. (2005). Treatment of optic neuropathy: new possibilities.
- Krause, L. (2015). Optic Neuritis . Retrieved from Healthline.
- Mayo Clinic. (2014). Optic neuritis . Obtained from Mayo Clinic.
- MSS. (2016). Optic neuritis . Obtained from Multiple Sclerosis Society.
- NIH. (2016). Optic neuritis . Obtained from MedlinePlus.
- Sánchez-Méndez, F. (2016). Optic nerve and vision disorders. Practical medical continuing education .
- Image source .