Importante

Acute cerebellar ataxia
Author
Mark E Helm, MD, MBA
Section Editors
Marc C Patterson, MD, FRACP
Stephen J Teach, MD, MPH
Deputy Editor
Alison G Hoppin, MD
Disclosures
Last literature review version 19.3: septiembre 2011 | This topic last updated: febrero 16, 2011 (More)
INTRODUCTION — Acute cerebellar ataxia is a syndrome which has been observed following many infectious diseases,including varicella, Epstein-Barr virus, roseola (human herpesvirus 6), enterovirus, rubeola, parvovirus, and mycoplasma infection [1-7]. The syndrome most often is seen in young children with the majority of cases occurring between two and five years of age [2,6,8].
The pathogenesis, clinical presentation, evaluation, and prognosis of acute cerebellar ataxia will be reviewed here. The differentialdiagnosis and evaluation of the child presenting with acute ataxia is discussed separately. (See "Approach to the child with acute ataxia".)
EPIDEMIOLOGY — Acute cerebellar ataxia usually occurs in children under six years of age [2,6,8]. The true incidence of this disorder is not known [1,6]. In one series, 39 cases requiring hospitalization were reported in an 11-year period from a facilityserving a population of roughly 60,000 children [6]. A review of acute cerebellar ataxia diagnosed over 24 months in the Netherlands identified an incidence of 0.75 cases per 100,000 individuals under 15 years of age [9]; 70 percent of these cases were treated in hospital.
PATHOGENESIS — Acute cerebellar ataxia is typically preceded by an acute febrile illness [2,6,10]. Varicella is involved in overone-fourth of cases [2,6]. Although acute cerebellar ataxia is the most common neurologic complication of varicella infection, it has been estimated that acute cerebellar ataxia occurs in only about 1 in 4000 varicella infections in children younger than 15 years of age [1]. The population study in the Netherlands estimated an even lower rate of 5 cases of acute cerebellar ataxia per 100,000 casesof varicella [9]. (See "Clinical features of varicella-zoster virus infection: Chickenpox", section on 'Neurologic complications'.)
Numerous other infectious agents have been implicated in the pathogenesis of acute cerebellar ataxia, including echovirus, coxsackievirus, Epstein-Barr virus, measles, human herpesvirus 6, mumps, herpes simplex virus I, parvovirus, typhoid fever, malaria, Borreliaburgdorferi (Lyme disease), and mycoplasma pneumoniae [7,11-13]. More rarely, the syndrome has been reported following vaccination for varicella, hepatitis B and rabies, without evidence of systemic infection [2,6,14,15].
The pathogenesis of the ataxia has not been established, but emerging evidence suggests that an autoimmune mechanism may be involved [2,15,16]. Antiviral antibodies andautoreactive antibodies against Purkinje cells, centrosomes, and myelin-associated glycoprotein have been isolated from cerebrospinal fluid in affected patients [2,4,16-19]. However, in other case reports, viral nucleic acids have been identified in the cerebrospinal fluid, suggesting that infection of brain tissue may contribute to the disorder [6].
Radiologic studies in patients with recent onset ofacute cerebellar ataxia generally are normal; if lesions are seen, they are usually limited to the cerebellum [2,10]. Single-photon emission computed tomography has demonstrated diminished perfusion of the cerebellum in patient reports involving children, but not adults, with acute cerebellar ataxia symptoms [20-22]. (See 'Imaging' below.)
CLINICAL PRESENTATION — Acute cerebellar ataxia ischaracterized by the acute onset of ataxia four days to three weeks after the inciting illness [2,6,11]. The symptoms are typically maximal at onset. Gait disturbance is the primary symptom, but the cerebellar dysfunction may be limited to fine motor control problems or tremor [2,4,6]. Associated symptoms may include nystagmus (roughly one-half of cases reported), slurred or garbled speech, vomiting,...