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.Purpose: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.

The phenotypic spectrum of dystonia in Mohr–Tranebjaerg syndrome

“…Oromandibular dystonia, which was present in our female proband (B‐1), may also be a feature of several other heredodegenerative conditions such as neuroacanthocytosis, neuroferrinopathy, and pantothenate kinase–associated neurodegeneration;8 however, they are not typically associated with profound HI. Other secondary dystonia syndromes may also be accompanied by deafness 8.…”

“…Together with the data from our 3 kindreds, we identified several trends in the distribution and progression of dystonia in MTS. First, whereas primary dystonia in adults typically remains focal,8 in MTS there is a gradual progression of dystonia to multifocal, segmental or generalized forms, regardless of age of onset 7, 9–12. Second, there is a predilection for onset in the upper limbs or craniocervical region.…”

Dystonia in Patients With Spinocerebellar Ataxia Type 2

“…According to recently proposed classification of dystonia, clinical recognition of dystonia syndromes is strongly recommended, given that this can provide valuable diagnostic clues . Syndrome of adult‐onset cerebellar ataxia accompanied with dystonia is probably rare and in its differential diagnosis includes screening for metabolic diseases, such as Wilson's disease, Nieman‐Pick type C, cerebrotendinous xanthomatosis, and so on, although in these cases dystonia and cerebellar signs develop in the context of broader clinical picture. Dystonia has also been described in recessive ataxias, such as ataxia‐teleangiectasia.…”

“…Dystonia has also been described in recessive ataxias, such as ataxia‐teleangiectasia. In particular, high prevalence of lower cranial dystonia in our patients suggests that SCA2 might be added to the list of diseases with prominent oromandibular dystonia, such as iron accumulation disorders, Wilson's disease, GM1 gansliosidosis, tardive dystonia, and so on.…”

Update on pediatric dystonias: etiology, epidemiology, and management

“…The etiology of pediatric dystonia is heterogeneous (Table 1). 4 The etiological classification distinguishes primary dystonia with no identifiable exogenous cause or evidence of neurodegeneration and secondary syndromes. Primary diseases may be divided in pure, plus, and paroxysmal.…”