Lewis-Sumner syndrome is the most common atypical form of chronic inflammatory demyelinating polyneuropathy (CIDP). In most patients, the disease is slowly progressive, which slows down the correct diagnosis. Timely diagnosis in some cases is also complicated by an abnormal primary lesion of the lower limb nerves in patients with Lewis-Sumner syndrome, for whom the typical clinical picture is upper flaccid distal paraparesis. The objective of the study is to determine the frequency of Lewis-Sumner syndrome (LSS), with the lower limb nerve onset; to characterize clinical and paraclinical characteristics of patients with the syndrome. Materials and Methods. The authors analyzed clinical data, results of stimulation electroneuromyography and ultrasound examination of peripheral nerves of 36 LSS patients. Results. The authors observed a high percentage (44 %) of LSS patients with lower limb nerve onset. However, changes in the neurophysiological and sonographic examination of the lower limb nerves, specific for CIDP, were not revealed. Changes typical of dysimmune neuropathy were verified only in the study of clinically intact long upper limb nerves. Conclusion. In asymmetric neuropathy of the lower limbs of idiopathic genesis, one should remember about LSS and, even despite the presence of symptoms only in the lower limbs, examine the peripheral nerves of the upper limbs. Key words: chronic inflammatory demyelinating polyneuropathy, Lewis-Sumner syndrome, atypical form. Синдром Льюиса – Самнера является наиболее частой атипичной формой хронической воспалительной демиелинизирующей полинейропатии (ХВДП). У большинства больных заболевание носит медленно прогрессирующий характер, что является одним из факторов увеличения сроков постановки верного диагноза. Своевременную диагностику в ряде случаев затрудняет и нехарактерное первичное поражение нервов ног у пациентов с синдромом Льюиса – Самнера, для которых типичной клинической картиной является верхний вялый дистальный парапарез. Цель исследования: определить частоту встречаемости синдрома Льюиса – Самнера (СЛС), дебютирующего с поражения нервов ног; охарактеризовать клинические и параклинические особенности больных с данным синдромом. Материалы и методы. Проанализированы клинические данные, результаты стимуляционной электронейромиографии и ультразвукового исследования периферических нервов 36 пациентов с СЛС. Результаты. Установлен высокий процент (44 %) встречаемости пациентов с СЛС с дебютом с поражения нервов ног. Однако специфические, характерные для ХВДП, изменения при нейрофизиологическом и сонографическом исследовании нервов ног не выявлены. Изменения, типичные для дизиммунной нейропатии, верифицированы только при исследовании клинически интактных длинных нервов рук. Выводы. В случаях асимметричной нейропатии нижних конечностей идиопатического генеза следует иметь настороженность в отношении СЛС и, даже несмотря на наличие симптоматики только в нижних конечностях, обследовать периферические нервы рук. Ключевые слова: хроническая воспалительная демиелинизирующая полинейропатия, синдром Льюиса – Самнера, атипичная форма.

Objective: linguistic and cultural adaptation of the original version of Berg Balance Scale (BBS) and assessment its psychometric properties.Patients and methods. The staff of the Validation Center of International Scales and Questionnaires of the Research Center of Neurology received consent from Katherine Berg to validate the BSS in Russia. We carried out the linguocultural ratification during the validation study and prepared a Russian version of the scale. To assess the psychometric properties of the scale (reliability, validity, and sensitivity), we evaluated 55 patients (30 females and 25 males) aged 22–88 years with different neurological disorders (vascular and demyelinating diseases of the central nervous system, peripheral neuropathy, and movement disorders). We analyzed the differences of the total BBS score and the number of patients with high and low risk of falls at the end of rehabilitation compared to baseline to assess the dynamics of changes.Results and discussion. We successfully performed the translation and linguocultural adaptation of the BBS. The scale represents a high level of validity (expert score: 8.6 out of 10 points), reliability (Pearson's correlation coefficient r=0.98, р<0.0001; Cronbach's alpha α=0.94 р<0.001; Cohen's kappa κ=0.71, p<0.0001) and sensitivity (р<0.0001). After a two-week rehabilitation course, the risk of falls significantly decreased (χ2 =4.42; р=0.035); however, the level of independence of movement did not change significantly (F=0.94; р=0.636).Conclusion. The Russian version of the BBS was officially adapted based on the results of the accomplished validation study and is recommended for use both in routine clinical practice and in clinical trials by neurologists and rehabilitologists. The scale is available for downloading by QR code and on the website of Validation Center of International Scales and Questionnaires of the Research Center of Neurology.

Сhronic inflammatory demyelinating polyneuropathy (CIDP) is the most prevalent acquired dysimmune neuropathy with clinical picture of symmetric motor and sensory disturbances. Since the first description of CIDP, many atypical variants have been described, which may reach up to 50% of cases. Diagnosis of atypical CIDP may be challenging due to different clinical presentation and treatment response. Current researches improve our knowledge about dysimmune neuropathies and highlight the importance of its classification. Nowadays CIDP is considered as a spectrum of disorders rather than a separate disease entity. Up to date, more than 15 diagnostic criteria have been proposed reflecting the complexity of СIDP diagnosis. Many polyneuropathies may mimic CIDP, therefore CIDP is frequently a diagnosis of exclusion. The key diagnostic instrument is electroneuromyography; however, the issues related to results misinterpretation and some technical aspects are the most important in CIDP misdiagnosis. Supportive instrumental and laboratory methods have variable sensitivity and specificity, making challenging CIDP diagnosis, especially its atypical forms. The importance of an early and accurate diagnosis of CIDP is supported by an effective pathogenic treatment, which affects the patient's prognosis and level of disability.

Introduction. Atypical variants of chronic inflammatory demyelinating polyneuropathy are marked by its clinical heterogeneity and variable disease course.Aim of the study. To describe clinical, anamnestic and neurophysiological features of patients with atypical variants of chronic inflammatory demyelinating polyneuropathy, characterized by benign disease course, minimal motor involvement and not required pathogenic therapy.Materials and methods. 8 patients (7 men (87 %) and 1 woman (13 %) at the age of 52–77 years) with atypical variants of chronic inflammatory demyelinating polyneuropathy were analyzed: 5 patients (62.5 %) with asymmetric variant – multifocal acquired demyelinating sensorimotor neuropathy and 3 patients (37.5 %) with sensory variant. All patients were observed at the Research Center of Neurology for the period of 2016– 2019. In each patient the proper clinical and laboratory evaluation was performed along with nerve conduction study and nerve ultrasound.Results. The disease duration at the time of first visit was 1–8 years. By INCAT disability score 3 (37.5 %) patients had 0 points (normal), 3 (37.5 %) patients – 1 point and 1 patient had 2 (25 %) points. Nerve conduction study showed multifocal, asymmetric demyelinating changes in motor nerves. For the whole period of observation all patients were stable, so no one required pathogenic therapy.Conclusion. Chronic inflammatory demyelinating polyneuropathy is a clinically heterogeneous disorder, required clinical suspicion in all patients over 50 years with features of multiple nerve involvement; nerve conduction study helps to detect typical changes, including subclinical ones. The primary strategy of management typical and atypical disease variants in stable course and minimal symptoms is a case follow-up with precise assessment of advantages and disadvantages of pathogenic therapy.

Intravenous high-dose immunotherapy is one of the highly effective proven treatments for a number of autoimmune diseases of the nervous system. Nowadays there is enough knowledge about the spectrum of side effects and approaches to their prevention and monitoring. Most of them are leveled by improving the technology of the production process, but anaphylactic reactions remain one of the uncontrolled, albeit rare, undesirable reactions. The development of allergic reactions is associated with the presence of antibodies to immunoglobulin class A (IgA) in the patient, which is manifested by a decrease in the level of IgA during routine immunological examination. The article provides a review of the literature on the prevalence of IgA deficiency, its causes. A modern view of the need for routine testing of IgA level before the course of intravenous immunotherapy, approaches to reduce the risk of developing serious adverse reactions in such cases is described. A clinical case of treatment of a patient with chronic inflammatory demyelinating polyneuropathy and a reduced level of IgA is presented.