title: Secondary dystonia-clinical clues and syndromic associations.
abstract: BACKGROUND
  Dystonia is a hyperkinetic movement disorder defined by involuntary sustained muscle spasms and unusual postures. Etiologically, dystonic syndromes can be broadly divided into primary and secondary forms, dystonia-plus syndromes and heredodegenerative forms. In particular, diagnosis of secondary dystonic syndromes can be challenging in view of the variety of causes.
  
  
  OBJECTIVE
  The purpose of this article is to highlight some clinical clues and syndromic associations as well as investigational findings which may be helpful in the approach to a patient with suspected secondary dystonia.
  
  
  METHODS
  We outline characteristic clinical and neuroimaging findings which may be directive in the diagnostic process of dystonia patients and facilitate making the correct diagnosis, thus allowing initiating the best treatment.
  
  
  RESULTS
  Secondary causes of dystonia include, among others, strategic brain lesions of various origins, metabolic disease, neurodegenerative conditions, and previous exposure to drugs or toxins. Presence of clinical signs including prominent oromandibular involvement, eye movement disorders, retinitis pigmentosa, deafness, peripheral neuropathy, parkinsonism or progressive dementia should alert the clinician to consider a secondary cause. Strategic lesions within the basal ganglia, but also within the brainstem, cerebellum or cortical areas may underlie dystonia and should thus be excluded.
  
  
  CONCLUSIONS
  When thorough clinical examination reveals features atypical of primary dystonia, syndromic associations may help the clinician to narrow down the list of differential diagnosis. Directive investigations like neuroimaging may confirm the clinical suspicion.
authors.affiliation: Section of Clinical and Molecular Neurogenetics at the Department of Neurology, University Luebeck, Maria-Goeppert-Str. 1, Luebeck, Germany and Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, Queen Square, London, U.K .
authors.forename: Susanne A
authors.initials: SA
authors.lastname: Schneider
authors.affiliation: Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College of London, Queen Square, London, U.K .
authors.forename: Kailash P
authors.initials: KP
authors.lastname: Bhatia
keywords: Anterior cerebral artery; Brain infarction; Chorea