Chronic Relapsing Inflammatory Optic Neuropathy (CRION)

Epidemiology of demyelinating diseases in Mexico: A registry-based study

BACKGROUND

Demyelinating diseases (DD) are a group of chronic neurological diseases associated with loss and injury of brain or spinal cord regions. These conditions could trigger impairment of neurological functions and disability from earlier stages of life. Epidemiological data on DD remains insufficient for decision-making in the Mexican healthcare system. This study aims to describe the epidemiology of DD based on data from Mexico's National Registry of Demyelinating Diseases.

METHODS

A cross-sectional, registry-based, observational study was performed. We analyzed 408 reports of multiple sclerosis (331, 81%), neuromyelitis optica spectrum disorder (67, 16%), chronic recurrent inflammatory optic neuropathy (5, 1%), clinically isolated syndrome (4, 0.9%), and autoimmune encephalitis (1, 0.2%) reported across 2021.

RESULTS

The time from first symptoms to diagnosis of any DD was about 3 years. A treatment failure history was detected in 40% of patients. It was estimated that NMOSD accounts for 20% of all disorders. There was evidence that the use of brand-name and generic IFN drug products lead to increased therapeutic failures.

CONCLUSION

Our research team suggests reinforcing educational programs and activities based on diagnosis and clinical management improvement to first-contact physicians and specialty doctors and promoting awareness in the whole population.

Treatment and Relapse Prevention of Typical and Atypical Optic Neuritis

Optic neuritis (ON) is an inflammatory condition involving the optic nerve. Several important typical and atypical ON variants are now recognized. Typical ON has a more favorable prognosis; it can be idiopathic or represent an early manifestation of demyelinating diseases, mostly multiple sclerosis (MS). The atypical spectrum includes entities such as antibody-driven ON associated with neuromyelitis optica spectrum disorder (NMOSD) and myelin oligodendrocyte glycoprotein antibody disease (MOGAD), chronic/relapsing inflammatory optic neuropathy (CRION), and sarcoidosis-associated ON. Appropriate and timely diagnosis is essential to rapidly decide on the appropriate treatment, maximize visual recovery, and minimize recurrences. This review paper aims at presenting the currently available state-of-the-art treatment strategies for typical and atypical ON, both in the acute phase and in the long-term. Moreover, emerging therapeutic approaches and novel steps in the direction of achieving remyelination are discussed.

Optical Coherence Tomography in Chronic Relapsing Inflammatory Optic Neuropathy, Neuromyelitis Optica and Multiple Sclerosis: A Comparative Study

Purpose: To examine the optical coherence tomography (OCT) features of the retina in patients with chronic relapsing inflammatory optic neuropathy (CRION) and compare them with those of neuromyelitis optica spectrum disorder (NMOSD), relapsing-remitting multiple sclerosis (RRMS) with and without optic neuritis (ON), and healthy controls (HC). Methods: In this retrospective cross-sectional study, we used spectral domain OCT to evaluate the retinal structure of 14 participants with CRION, 22 with NMOSD, 40 with RRMS with unilateral ON, and 20 HC. The peripapillary retinal nerve fiber layer (pRNFL), total macular volume (TMV), and papillomacular bundle (PMB) were measured, and intra-retinal segmentation was performed to obtain the retinal nerve fiber (RNFL), ganglion cell (GCL), inner plexiform (IPL), inner nuclear (INL), outer plexiform (OPL) and outer nuclear (ONL) layer volumes. Results: The global pRNFL [39.33(±1.8) µm] and all its quadrants are significantly thinner in CRION compared with all other groups (p < 0.05). CRION patients have decreased volumes of TMV, RNFL, GCL, and IPL compared with all other groups (p < 0.05). Conclusion: Severe thinning in pRNFL and thinning in intra-retinal segments of IPL, GCL, RNFL, and TMV could be helpful in differentiating CRION from NMOSD and RRMS.