Movement disorders encompass a diverse group of neurological conditions characterized by abnormal voluntary or involuntary movements. These disorders can be classified broadly into hyperkinetic and hypokinetic disorders. Excessive, involuntary movements, including tremors, dystonia, chorea, and myoclonus characterize hyperkinetic disorders. Tremors are rhythmic, involuntary movements occurring at rest or during movement. Dystonia involves sustained muscle contractions, leading to twisting and repetitive movements or abnormal postures. Chorea manifests as brief, irregular, involuntary movements that flow from one body part to another. Myoclonus consists of sudden, brief muscle contractions, either spontaneous or in response to a stimulus. Hypokinetic disorders are characterized by a lack of movement or difficulty initiating movement, as seen in Parkinson's disease and Parkinsonism. Parkinson's disease is a progressive neurological disorder that primarily affects movement, causing tremors, stiffness, and difficulty with balance and coordination. Parkinsonism refers to a group of disorders with similar symptoms to Parkinson's disease but with different underlying causes. Diagnosing movement disorders involves a thorough clinical evaluation, including a detailed medical history and physical examination. Neuroimaging studies such as MRI, CT scans, and functional imaging techniques may be used to assess brain structure and function. Additionally, laboratory tests, including genetic testing and biochemical markers, can help diagnose certain movement disorders.

Secondary movement disorders (SMDs) represent a heterogeneous group of neurological conditions characterized by abnormal, involuntary movements resulting from various underlying causes. This comprehensive review aims to thoroughly understand SMDs, including their epidemiology, pathophysiology, clinical manifestations, diagnostic approach, and management strategies. SMDs encompass a spectrum of movement abnormalities, including dystonia, chorea, athetosis, myoclonus, tics, and tremors. They can arise from a multitude of etiologies, such as drug-induced effects, post-infectious processes, metabolic disturbances, and structural brain lesions. The epidemiology of SMDs varies depending on the underlying cause, with some conditions being more prevalent in specific populations or age groups. Understanding the pathophysiology of SMDs is crucial for accurate diagnosis and targeted management. Diagnosing SMDs requires a comprehensive approach, including a detailed history, physical examination, laboratory investigations, neuroimaging studies, and sometimes electrophysiological studies. Management of SMDs is multifaceted and may involve pharmacological, non-pharmacological, and surgical interventions. Individualized treatment plans are essential, considering the underlying cause, severity of symptoms, and patient preferences. Emerging concepts in the field of SMDs include advancements in genetic research, identification of biomarkers, and development of novel therapeutic approaches. There is a growing focus on patient-centered care and improving the quality of life for individuals with SMDs. In conclusion, SMDs pose diagnostic and therapeutic challenges, requiring a multidisciplinary approach for optimal management. Continued research and collaboration are essential for advancing our understanding and treatment of these complex disorders.

Opsoclonus-myoclonus-ataxia syndrome is a heterogeneous constellation of symptoms ranging from full combination of these three neurological findings to varying degree of isolated individual sign. Since the emergence of coronavirus disease 2019 (COVID-19), neurological symptoms, syndromes and complications associated with this multi-organ viral infection have been reported and the various aspects of neurological involvement are increasingly uncovered. As a neuro-inflammatory disorder in nature, one would expect to observe opsoclonus-myoclonus syndrome after a prevalent viral infection in a pandemic scale, as it has been the case for many other neuro-inflammatory syndromes. We report seven cases of opsoclonus-myoclonus syndrome presumably para-infectious in nature and discuss their phenomenology, their possible pathophysiological relationship to COVID-19 and diagnostic and treatment strategy in each case. Finally we review the relevant data in the literature regarding the opsoclonus-myoclonus syndrome and possible similar cases associated with COVID-19 and its diagnostic importance for clinicians in various fields of medicine encountering COVID-19 patients and its complications.