Background: Demyelinating disorders are a group of chronic immune-mediated diseases affecting myelinated axons in the central nervous system, which lead to life-long disability. In Mongolia, the last regional prevalence study was conducted in 2010. Our study objective is to describe the current prevalence of multiple sclerosis (MS) and other demyelinating disorders in Mongolia. : Aim Materials and Methods: We registered MS, neuromyelitis optica spectrum disease (NMOSD), myelin oligodendrocyte glycoprotein (MOG), and acute disseminated encephalomyelitis (ADEM) cases diagnosed according to the 2017 McDonald criteria, the 2023 NMOSD diagnostic criteria, International MOGAD Panel proposed criteria. Results: The study was conducted in all tertiary, 7 regional, and 20 provincial hospitals across Mongolia and has collected comprehensive data on 965 patients. The prevalence of total demyelinating disorders was estimated to be 27.2, MS 15.6, NMOSD 5.6, MOG 0.06, and ADEM 0.9 per 100,000 total population, respectively. The prevalence of demyelinating disorders between provinces was compared in order of geographical latitude, from lowest to highest, and was statistically significant. Latitude is associated strongly with the prevalence of demyelinating disorders (p=0.006, 95% CI 14.3-22.4, Pearson correlation=0.603) and moderately with the prevalence of MS (p=0.028, 95% CI 9.39-15.6, Pearson correla tion=0.503). Conclusion In Mongolia, the prevalence of MS has significantly increased and can be considered at medium risk, but still much lower than that in Western countries. The prevalence of NMOSD is almost similar to other Asian countries. An obvious latitude gradient for demyelinating disorders was observed in the Mongolian population.

Background: Multidrug-induced long QT syndrome is a serious heart rhythm disorder where multiple medications prolong the QT interval on an electrocardiogram, increasing the risk of a potentially fatal arrhythmia. Long QT syndrome is characterised by heart rate corrected QT interval prolongation and life-threatening arrhythmias, such as polymorphic ventricular tachycardia, Torsades de pointes leading to syncope and sudden death. Case: 21-year-old woman required resuscitation from an apparent cardiac arrest that had occurred after status epilepticus. The woman was diagnosed with long QT syndrome, cardiac channelopathy. She had a long history of syncope, seizure and palpitations. Family history was non-contributory. Home medications included levetiracetam 500 milligrams orally twice and fluoxetine 20 milligrams orally once a day which the patient reported non-compliance with. Levetiracetam is a widely used anti-epileptic medication secondary to its favorable safety profile. To our knowledge, there are few other case reports documenting torsades de pointes after levetiracetam administration, and specifically our case report will be the first documenting cardiac arrest after multidrug administration. Long QT syndrome is not often included in the differential diagnosis of epileptic and non-epileptic seizures. Early recognition of the syndrome is very important because of prognostic and therapeutic consequences. Conclusion Although no hereditary cause was confirmed, this case represents Torsades de Pointes triggered by multiple medications—including long-term low-dose carbamazepine, fluoxetine, diazepam, and high-dose levetiracetam—on a background of probable Romano–Ward syndrome or predisposition to QT prolongation. The arrhythmia progressed to cardiac arrest, requiring ICD implantation.