In this article, the author reviews the wide spectrum of movement disorders associated with infectious agents. Although these complications tend to be more frequent in parts of the world plagued by endemic infections, they are also seen in association with sporadic cases of infections. With better control of HIV (human immunodeficiency virus) infection, there has been a decline of movement disorders observed in these patients. There is a comprehensive discussion of Sydenham chorea and other problems related to beta-hemolytic group A streptococcus. Other infections, such as Japanese encephalitis, remain an important cause of movement disorders in some parts of the world. The pathogenesis of Parkinson disease might be related to changes in gut microbiota leading to mutation of alpha-synuclein. Epidemiological data convincingly point out that there is a relationship between hepatitis C virus and increased risk of development of Parkinson disease. The pandemic of COVID-19 has triggered a global interest in the role of infectious agents in human diseases, including movement disorders. One year after its beginning, it is clear that up to 30% of patients with SARS-CoV-2 develop neurologic complications, including movement disorders.
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• Encephalitides of various etiologies can cause movement disorders, mainly parkinsonism and dystonia.
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• Emerging infections like West Nile virus, dengue, and Zika are associated with the development of movement disorders.
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• The introduction of highly active antiretroviral therapy has resulted in a decline of neurologic complications of HIV infection, including movement disorders.
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• Sydenham chorea is the most common cause of acute chorea in children worldwide.
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• There is evidence of the association between hepatitis C virus and increased risk of development of Parkinson disease.
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• Movement disorders happen in COVID-19. The most common phenomena are myoclonus and cerebellar ataxia. Other features include tremor, parkinsonism, chorea, and dystonia.
Historical note and terminology
Rheumatic chorea was the first described movement disorder related to an infectious agent. Despite the detailed clinical description provided by Thomas Sydenham in 17th century England, its causal relationship with streptococcal infection was only firmly established in the middle of the 20th century (228). The incidence of Sydenham chorea has drastically dropped in North America and Western Europe since 1960. Contemporary interest in this condition was fueled by its persistence as an important health problem in developing countries, as well as by the hypothesis that Streptococcus-induced antibodies targeted at basal ganglia neurons might account for tics and behavioral abnormalities among children (37). However, even in those parts of the world there has been a remarkable decline of the incidence of rheumatic fever. The current weight of evidence leans towards the nonexistence of a relationship between Streptococcus and neuropsychiatric abnormalities outside the context of Sydenham chorea.
Another important landmark in the history of infectious movement disorders was the encephalitis lethargica pandemic, also known as Von Economo disease for the physician who described it. The disease started spontaneously in several different central European cities around 1916. Over the next 11 years, it spread relentlessly around the world, leaving an estimated half million people dead or disabled. From the outset, it became established that a subset of surviving patients developed postencephalitic parkinsonism (248). As mysteriously as it began, this disease virtually disappeared. Curiously, its causative agent remains unknown to date. Even a study employing up-to-date methodology to search for influenza virus in the brain of patients who died of encephalitis lethargica failed to identify any viral gene (142). It is uncertain whether recent cases with similar clinical pictures represent the same condition described by von Economo.
In the last 2 decades of the 20th century, AIDS was the infectious disease to receive the largest scientific and public attention. It became acknowledged that movement disorders are among the neurologic complications of patients who are HIV positive (24). The introduction of highly active antiretroviral therapy has led, however, to a decline in the frequency of occurrence of HIV-related neurologic disorders (155; 38).