Non-progressive cerebellar ataxia and previous undetermined acute cerebellar injury: a mysterious clinical condition

Abstract

Ataxic syndromes are conditions that result from the involvement of cerebellar structures or from a combination of cerebellar and extra-cerebellar lesions affecting the brainstem, thalamus, spinal cord (spinocerebellar and posterior cord tracts), vestibulocerebellar system and frontal lobes. Cerebellar ataxias are a heterogeneous group of diseases comprising genetic and acquired etiologies 1 , giving rise to lack of motor coordination, especially in fine coordinated voluntary movements. Speech disorders, movement decomposition, intention tremor, disbasia, nystagmus and other complex oculomotor disturbances, hypotonia with pendular reflexes, delayed motor milestones and the so-called cognitive-affective cerebellar syndrome may also arise as a consequence of different cerebellar disorders 2,3 . Cerebellar ataxias can be subdivided into two major categories taking into account inheritance and etiological factors: hereditary ataxias, including autosomal dominant spinocerebellar ataxias (SCA) and episodic ataxias, autosomal recessive ataxias, non-progressive congenital ataxias, mitochondrial ataxias, X-linked cerebellar ataxias; and sporadic or acquired cerebellar ataxias (including non-hereditary degenerative ataxias). From a clinical point of view, cerebellar ataxias can be divided in intermittent or episodic, non-progressive or stable (including the congenital cerebellar ataxias) and progressive ABSTRACT Cerebellar ataxias represent a wide group of neurological diseases secondary to dysfunctions of cerebellum or its associated pathways, rarely coursing with acute-onset acquired etiologies and chronic non-progressive presentation. We evaluated patients with acquired non-progressive cerebellar ataxia that presented previous acute or subacute onset. Clinical and neuroimaging characterization of adult patients with acquired non-progressive ataxia were performed. Five patients were identified with the phenotype of acquired nonprogressive ataxia. Most patients presented with a juvenile to adult-onset acute to subacute appendicular and truncal cerebellar ataxia with mild to moderate cerebellar or olivopontocerebellar atrophy. Establishing the etiology of the acute triggering events of such ataxias is complex. Non-progressive ataxia in adults must be distinguished from hereditary ataxias.

Non-progressive cerebellar ataxia with previous acute cerebellar injury of undetermined origin: a puzzling neurological disorder

“…In 2010, Klockgether published a very interesting study of sporadic ataxia with adult onset and discussed different etiologies of this condition, including genetic causes, with single gene mutations (e.g., Friedreich' s ataxia and SCA type 6), and non-genetic causes (e.g., drug-induced cerebellar ataxia and immune-mediated cerebellar ataxia with cerebellar inflammation), as well as cases of multiple system atrophy type C and sporadic adultonset ataxia of unknown etiology (SAOA) 6 . However, the cases of non-progressive cerebellar ataxia described by Pinto et al are associated with previous acute or subacute onset of undetermined origin, and most started in the second decade of life 5 . One attractive hypothesis could be a non-progressive cerebellar ataxia due to previous acute viral cerebellitis or postinfectious cerebellar ataxia with an autoimmune mechanism.…”

“…In this issue of Arquivos de Neuro-Psiquiatria, Pinto et al report an interesting and puzzling non-progressive cerebellar ataxia with previous acute cerebellar injury of undetermined origin 5 . The authors studied five adult patients with acquired non-progressive cerebellar ataxia (mean age of onset = 20.8 years) associated with cerebellar or olivopontocerebellar atrophy who presented with previous acute or subacute onset (mean value = 10 days) without a known etiology for the condition 5 . They discuss in great detail various possible etiologies of this mysterious condition, including neurogenic etiologies (either unidentified because of incomplete genetic investigation or associated with genetic diseases with mild phenotypes or formes frustes) and inborn errors of metabolism (undiagnosed because of incomplete screening), but failed to find a specific etiology in their series of patients 5 .…”

“…They include sporadic cerebellar ataxias associated with infections (chickenpox virus, Epstein-Barr virus) and toxic agents (previous drug exposure) and autoimmune cerebellar ataxias 2,3,4 . A peculiar group of non-progressive cerebellar ataxias can be associated with previous acute or subacute cerebellar insult of unknown etiology 5 . In this issue of Arquivos de Neuro-Psiquiatria, Pinto et al report an interesting and puzzling non-progressive cerebellar ataxia with previous acute cerebellar injury of undetermined origin 5 .…”

“…A peculiar group of non-progressive cerebellar ataxias can be associated with previous acute or subacute cerebellar insult of unknown etiology 5 . In this issue of Arquivos de Neuro-Psiquiatria, Pinto et al report an interesting and puzzling non-progressive cerebellar ataxia with previous acute cerebellar injury of undetermined origin 5 . The authors studied five adult patients with acquired non-progressive cerebellar ataxia (mean age of onset = 20.8 years) associated with cerebellar or olivopontocerebellar atrophy who presented with previous acute or subacute onset (mean value = 10 days) without a known etiology for the condition 5 .…”

“…The authors studied five adult patients with acquired non-progressive cerebellar ataxia (mean age of onset = 20.8 years) associated with cerebellar or olivopontocerebellar atrophy who presented with previous acute or subacute onset (mean value = 10 days) without a known etiology for the condition 5 . They discuss in great detail various possible etiologies of this mysterious condition, including neurogenic etiologies (either unidentified because of incomplete genetic investigation or associated with genetic diseases with mild phenotypes or formes frustes) and inborn errors of metabolism (undiagnosed because of incomplete screening), but failed to find a specific etiology in their series of patients 5 . While most published cases of non-progressive ataxia are described in early childhood, have a congenital etiology (e.g., cerebellar hypoplasia) and are frequently accompanied by mental retardation, a significant number of cases are unclassifiable 2,3,4 .…”