Diagnostic Criteria for Primary Autoimmune Cerebellar Ataxia\u2014Guidelines from an International Task Force on Immune-Mediated Cerebellar Ataxias

Marios Hadjivassiliou,Sven Jarius,Nigel Hoggard,Mario Manto,Maarten Titulaer,Hiroshi Mitoma,Francesc Graus,Jerome Honnorat,Ptolemaios Sarrigiannis

doi:10.1007/s12311-020-01132-8

Abstract

Aside from well-characterized immune-mediated ataxias with a clear trigger and/or association with specific neuronal antibodies, a large number of idiopathic ataxias are suspected to be immune mediated but remain undiagnosed due to lack of diagnostic biomarkers. Primary autoimmune cerebellar ataxia (PACA) is the term used to describe this later group. An International Task Force comprising experts in the field of immune ataxias was commissioned by the Society for Research on the Cerebellum and Ataxias (SRCA) in order to devise diagnostic criteria aiming to improve the diagnosis of PACA. The proposed diagnostic criteria for PACA are based on clinical (mode of onset, pattern of cerebellar involvement, presence of other autoimmune diseases), imaging findings (MRI and if available MR spectroscopy showing preferential, but not exclusive involvement of vermis) and laboratory investigations (CSF pleocytosis and/or CSF-restricted IgG oligoclonal bands) parameters. The aim is to enable clinicians to consider PACA when encountering a patient with progressive ataxia and no other diagnosis given that such consideration might have important therapeutic implications.

Highlights

Immune-mediated cerebellar ataxias (IMCA) include ataxias where the trigger is known, e.g. paraneoplastic cerebellar degeneration (PCD) [1], gluten ataxia (GA) [2], post-infectious cerebellitis (PIC) [3] as well as ataxias where neuronal antibodies have been convincingly shown to be directly involved in the pathogenesis of the ataxia
The task was commissioned by the Society for Research on the Cerebellum and Ataxias (SRCA)
In a recent prospective study, out of a total of 1500 patients with progressive ataxia, IMCAs accounted for 26% [17]

Summary

Introduction

Immune-mediated cerebellar ataxias (IMCA) include ataxias where the trigger is known, e.g. paraneoplastic cerebellar degeneration (PCD) [1], gluten ataxia (GA) [2], post-infectious cerebellitis (PIC) [3] as well as ataxias where neuronal antibodies have been convincingly shown to be directly involved in the pathogenesis of the ataxia. A task force comprising clinicians with an interest and extensive clinical experience in the management of IMCA was formed in 2017 at the request of the Society for Research on the Cerebellum and Ataxias (SRCA) The aim of this international task force was to use their clinical expertise in devising consensus diagnostic criteria in an attempt to assist clinicians to suspect PACA as a potential diagnosis amongst patients with otherwise idiopathic sporadic ataxia. This is a very critical step enabling the consideration of early therapy aiming to preserve or restore cerebellar reserve

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Conclusion