Primary dystonia

Mary Ann Thenganatt MD (Dr. Thenganatt of the University of Pennsylvania has no relevant financial relationships to disclose.)
Joseph Jankovic MD, editor. (Dr. Jankovic, Director of the Parkinson's Disease Center and Movement Disorders Clinic at Baylor College of Medicine, received research funding from Allergan, Allon, Ceregene, Chelsea, EMD Serono, Impax, Ipsen, Lundbeck, Medtronic, Merz, and Teva, and compensation for his services as a consultant or an advisory committee member by Allergan, Auspex, EMD Serono, Lundbeck, Merz, Neurocrine Biosciences, and Teva.)
Originally released September 27, 1993; last updated April 25, 2016; expires April 25, 2019

This article includes discussion of primary dystonia, idiopathic torsion dystonia, and dystonia. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.

Overview

Dystonia is a movement disorder characterized by patterned, twisting movements of the body that can result in abnormal postures. Primary dystonia refers to dystonia without other neurologic findings besides tremor. Primary dystonia is often familial but can be sporadic, especially in adults. Besides an association with a genetic mutation, primary dystonia is not secondary to an underlying structural lesion, metabolic disturbance, or medication. There are various forms of primary dystonia that will be described in this article.

Key points

 

• Patients present with pure dystonia with the exception of tremor.

 

• Atypical features such as cognitive impairment, seizures, long tract signs, and retinal findings would suggest secondary causes.

 

• Primary dystonia is often genetic in children and adolescents, whereas sporadic primary dystonia, such as blepharospasm and cervical dystonia, is more common in adults.

 

• Genetic testing should be considered in younger patients or those with a family history.

 

• Treatment can include oral medications, botulinum toxin injections, and deep brain stimulation.

Historical note and terminology

The term "dystonia" was coined by Oppenheim in 1911 when he introduced the term “dystonia musculorum deformans” to describe 4 individuals in whom “muscle tone was hypotonic at one occasion and in tonic muscle spasm at another, usually, but not exclusively, elicited upon voluntary movements” (Oppenheim 1911). He stressed that there was no loss of muscle power, change in sensation, or psychological illness. For a large part of the 20th century, dystonia was considered psychogenic by many, until the 1970s when many characteristics of idiopathic torsion dystonia were further described (Marsden and Harrison 1974). In 1984, the Dystonia Medical Research Foundation provided the first consensus definition of dystonia consisting of “sustained muscle contractions, frequently causing twisting and repetitive movements, or abnormal postures” (Fahn et al 1987). An international panel of dystonia experts proposed a revised definition: “dystonia is a movement disorder characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements, postures, or both. Dystonic movements are typically patterned, twisting, and may be tremulous. Dystonia is often initiated or worsened by voluntary action and associated with overflow muscle activation” (Albanese et al 2013).

The nomenclature used to describe dystonia has evolved over time, with dystonia musculorum deformans being replaced by idiopathic torsion dystonia and then primary dystonia (Bressman and Saunders-Pullman 2013). Dystonia has classically been categorized along 3 axes: age at onset, body distribution, and etiology. The international panel proposed classifying dystonia in 2 categories: clinical characteristics and etiology.

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