A09 The differential diagnosis of chorea

Abstract

Background The term “chorea” is derived from the Greek term for dance, and suggests the fluidity of the movements, but not their arhythmicity. The movements can involve any body part and typically flit rapidly from region to region in an irregular, unpredictable, manner. The underlying pathophysiology is likely to be an imbalance of the activities of the direct and indirect basal ganglia pathways. The multitude of possible causes of chorea may be indicative of the vulnerability of this balance to disruption. Chorea may be a feature of metabolic disturbances and of structural lesions, which appear to affect neurotransmission in an apparently identical manner to that seen in neurodegenerative diseases. Aims In my talk I will describe an approach to diagnosing the patient with chorea, guided by informative aspects of the history, examination, and diagnostic tests. Methods I will systematically review causes of chorea which can be identified by features of personal and family history, neurological examination, and specific diagnostic tests. Results Although chorea can appear phenomenologically the same, regardless of underlying aetiology, by focusing upon specific features we can narrow down the differential diagnosis. Conclusions This movement disorder can be due to a large number of neurological disorders and diagnosis can be challenging. There are a number of well-characterised genetic disorders which typically cause this movement disorder, and others where it may occur less often, for example as part of a mixed movement disorder. Advances in molecular medicine have facilitated the recognition of atypical presentations of genetically-defined disorders, such as when the age of onset is later than is typical. The work-up of the patient with chorea can be extensive, expanding every year, and yet some patients inevitably remain undiagnosed.