RT Book, Section A1 de Gusmão, Claudio M. A1 Waugh, Jeffrey L. A2 Shah, Samir S. A2 Kemper, Alex R. A2 Ratner, Adam J. SR Print(0) ID 1157320070 T1 Ataxia T2 Pediatric Infectious Diseases: Essentials for Practice, 2e YR 2019 FD 2019 PB McGraw-Hill Education PP New York, NY SN 9781259861536 LK accesspediatrics.mhmedical.com/content.aspx?aid=1157320070 RD 2024/03/29 AB Ataxia is defined as the inability to generate a normal voluntary movement trajectory that cannot be attributed to weakness or involuntary muscle activity.1 The word derives from Greek and means without order, referring to disorganized, poorly coordinated, or clumsy movments.2 The disorder may be caused by dysfunction of the cerebellum or its immediate projections, and is traditionally referred to as cerebellar ataxia. In such cases, ataxia may involve appendicular (e.g., limb) or axial (e.g., truncal) control, often affecting balance and gait. Cerebellar ataxia is estimated to affect 26 in 100,000 children worldwide.3 Injuries to the proprioceptive system may also present with clumsy, disorganized movements, known as sensory ataxia. Finally, vestibular injury may affect posture and balance, which much be distinguished from ataxia. This chapter focuses on symptoms, signs, and etiologies of cerebellar ataxia, with an emphasis on infectious and para/postinfectious causes.