Peripheral dystonia is defined as sustained muscle contractions, frequently causing twisting and repetitive movements, or abnormal postures triggered by trauma to the peripheral or cranial nerves. Although a cause-and-effect relationship between central nervous system injury and subsequent dystonia is well established, the existence of such a relationship following peripheral injury is still a subject of controversy. There is increasing evidence, largely from clinical reports based on a strong temporal-anatomical relationship, supporting the association between peripheral nerve trauma and dystonia. In this article, the authors discuss the mechanisms and the clinical characteristics of peripherally induced movement disorders and address the controversies existent in the field. This review focuses on the following fundamental questions: (1) What are possible underlying mechanisms of peripherally induced dystonia? (2) What factors predict or predispose an individual to the development of dystonia following peripheral injury? (3) What are the clinical characteristics of dystonic movements in peripheral dystonia compared to primary dystonia? (4) What are the prognoses and long-term outcomes in patients with peripheral dystonia? In addition, the latest evidence in the mechanisms of peripherally induced dystonia and treatment options are reviewed.
• Peripheral dystonia is a secondary dystonia produced by trauma to peripheral and cranial nerves.
• Peripheral dystonia is the result of maladaptive changes in the cerebral cortex in response to altered peripheral input.
• In contrast to primary dystonia, peripherally induced dystonia is characterized by a fixed posture, contractures, and absence of sensory tricks.
• Peripheral dystonia is often associated with psychogenic movement disorders.
Historical note and terminology
Dystonia refers to a syndrome of sustained muscle contractions, frequently causing twisting and repetitive movements or abnormal postures (Fahn et al 1998). In primary dystonia the cause is genetic or unknown, whereas in secondary dystonia an identifiable trigger is present, such as a metabolic, heredodegenerative, or toxic trigger. Peripheral dystonia is a form of secondary dystonia induced by trauma to the peripheral nerves, nerve roots, or cranial nerves. Secondary dystonia is often accompanied by neurologic deficits, begins and occurs suddenly at rest, and develops mainly as the result of environmental factors that cause insult to the brain (Calne and Lang 1988). Secondary dystonias can be caused by focal brain lesions, neurodegenerative disorders, metabolic disorders, and several drugs and chemicals that affect the basal ganglia, thalamus, or brainstem (Table 1). Although a cause-and-effect relationship between central nervous system injury and subsequent dystonia is well established, the existence of such a relationship following peripheral injury is still a subject of controversy (Jankovic 2001; Weiner 2001).
Table 1. Complete List of Known Causes of Secondary Dystonias
• Perinatal cerebral injury
- Athetoid cerebral palsy
- Delayed onset dystonia
• Encephalitis, infectious and postinfectious
- Reye syndrome
- Subacute sclerosing leukoencephalopathy
- Wasp sting
- Human immunodeficiency virus
• Head trauma
• Cervical cord injury or lesion
• Peripheral injury
• Brainstem lesion, including pontine myelinolysis
• Primary antiphospholipid syndrome
• Focal cerebral vascular injury
• Brain tumor
- Dopamine D2 receptor blocking agents: acute dystonic reaction or tardive dystonia
• Toxicants (eg, Mn, CO, carbon disulfide, cyanide, methanol, disulfiram, 3-nitropropionic acid)
• Metabolic, such as hypoparathyroidism
Adapted from (Fahn et al 1998)
The concept of peripheral trauma as a causative factor of dystonia is not new. In 1888, Gowers reported a case of cervical dystonia after a neck injury and mentioned a case of a naval officer who developed writer's cramp after spraining his thumb (Gowers 1888). Wilson also believed that occupational cramps were sometimes precipitated by injury such as a sprain (Wilson 1966). There is growing support for the hypothesis that peripheral trauma may cause movement disorders, such as tremor, dystonia, and parkinsonism. However, no prospective data have been reported, and the evidence comes largely from clinical reports based on a strong temporal-anatomic relationship between trauma and dystonia. Studies have linked peripheral dystonia with complex regional pain syndrome (CRPS) and provided new evidence to support the cause-effect relationship between trauma and peripheral dystonia (van Hilten et al 2007; Jankovic 2009; Maihofner et al 2010; Kumar and Jog 2011). This review will focus on the following fundamental questions: (1) What are possible underlying mechanisms of peripherally induced dystonia? (2) What factors predict or predispose an individual to the development of dystonia following peripheral injury? (3) What are the clinical characteristics of dystonic movements in peripheral dystonia compared to primary dystonia? (4) What are the prognoses and long term outcomes in patients with peripheral dystonia?
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