The Treatment of the Choreas and Athetotic Dystonias R. B. GODWIN-AUSTEN, md,frcp Neurologist, Nottingham and Derby Hospitals and Nottingham University Medical School Although neurology has perhaps been regarded as a receptors and that the blockade of these same receptors somewhat academic specialty, an increasingly thera- (or the reduction in dopamine activity in the brain) peutic orientation in recent times is nowhere better might relieve the abnormal movements. This simple exemplified than in the diseases that affect the basal model is only partly satisfactory for some of the choreas ganglia. The 'extrapyramidal' diseases were the con- and is inadequate as an explanation in the athetotic ditions least satisfactorily explained on the basis of dystonias where our understanding of neurochemistry correlation between morbid anatomical change and remains minimal. But a significant proportion of patients physical signs. From the time of Parkinson himself until with abnormal movement disorders can now be helped by the early years of this century the anatomical site of the medical means and in these cases a knowledge of relevant lesion in Parkinson's disease remained obscure, largely neuropharmacology is necessary. because the pathological changes are subtle, whereas the changes in neurochemistry of the Parkinsonian brain were shown to be impressive directly the relevant techniques became available to demonstrate them (Ehringer and Horniekiewicz, 1960). Definition the choreas and torsion seldom Similarly, dystonias When or about disorders of movement show prominent morbid anatomical changes and these discussing writing there is a in and definition. It is not conditions cannot be and studied in the difficulty description reproduced unknown for two to use dif- experimental animal. But the emphasis for the genesis of experienced neurologists ferent terms to describe a patient with a abnormal these conditions has been shifted to a study of chemical single movement disorder. There are also terms that sometimes changes, especially since a number of drugs have caused seem to confuse, such as choreo-athetosis, or disorders that are similar to or identical with those oc- merely terms derived from neuropathology which, in a clinical curring naturally. As a direct result of these studies a setting, may be purely speculative (e.g. 'progressive number of drugs capable of reducing or suppressing pallidal atrophy'). The simplest and most satisfactory many of the symptoms have become available. The classification is that suggested by Marsden and Parkes diagnosis of extrapyramidal diseases is therefore no (1973), who divided abnormal movements into tremor, longer an academic exercise but an essential prerequisite to chorea, myoclonus, tics and athetotic dystonia. There is the effective management of the patient. seldom difficulty in distinguishing tremor from other Patients suffering from diseases causing chorea or dyskinesias since it is a regular rhythmical movement. athetotic dystonia present a bizarre appearance and are Chorea and myoclonus may be difficult or impossible to sufficiently unusual to make confident diagnosis the distinguish by clinical observation. Chorea is exception, although levodopa dyskinesias have made generally defined as irregular random and jerky movements that what was a very much more common- formerly rarity are continuous. In the movements are Place. Parkinson's disease provided the classical model of myoclonus usually a intermittent and consist of separate jerks or twitches that disease whose pathology is characterised by a depletion ?f may be Similarly, tics may be in- cerebral dopamine (and where the features of the stereotyped. distinguishable from myoclonus by observation but are disease can be produced by blockade of dopaminergic characterised by the subject being able to suppress the brain synapses) while relief can be obtained by treatment WJth movement partially by an effort of will that is ac- drugs active at the dopaminergic receptor (dopa- companied by a build-up of nervous tension. The feeling ^uie, apomorphine, bromocriptine). With the appear- ance of nervous tension is immediately relieved by the ab- of dopa dyskinesias the possibility arose that an normal movement. Athetotic dystonia is characterised analogous situation might exist ?that dyskinesias were by abnormal movements that are random, slow and caused by the reaction to dopamine of abnormal brain writhing in nature. They are usually associated with article is based on a paper read at the College disturbance of posture. C?nference held at Nottingham in September Any abnormal movement may be generalised, or may jgyWna^ involve predominantly proximal and trunk musculature J?urnal of the Royal College of Physicians of London Vol. 13 No. 1 January 1979 35 or, alternatively, the distal muscles. Thus, a proximal significant intracranial calcification. tremor may be called titubation when it involves the head and neck, and proximal unilateral chorea is often called The Choreas hemiballismus. abnormal movements be Similarly, may severe When chorea is the diagnosis may be obvious. The focal or torticollis is an generalised: spasmodic example random jerking movements causing grimacing and of a focal dystonia, while tardive phenothiazine dyskin- purposeless twitching and twisting movements of the esia is an example of a focal chorea. limbs are characteristic. In the mild case, doubt may arise as to whether the movements are nervous restless- ness, particularly in a condition such as thyrotoxicosis Diagnosis where chorea may develop as part of the disease, or in cases where for There are a number of features in the history and on psychiatric phenothiazines, example, may be used and the is therefore at risk from general examination that must be sought in any patient being patient tardive if presenting with a disorder associated with abnormal dyskinesia. Repeated observation, necessary after medication with a small dose of involuntary movements. In the young patient, birth benzodiazepine, settle the matter. In chorea is history and childhood development is important in may children, fortunately rare since the incidence of chorea distinguishing the congenital from the acquired; birth Sydenham's has declined, but the distinction between and chorea anoxia or injury and a history of neonatal jaundice may 'fidgets' be difficult, and necessitate more than one be relevant. In the past medical history an encephalitic may again of observation. illness is still important, as is any history of rheumatic period The commonest cause of chorea is the treatment fever. The family history and possibility of consanguinity today of Parkinsonism with the remain- should always be noted. Drugs, especially phenothiazines, levodopa and, among levodopa, the contraceptive pill and anticonvulsants, ing causes, drugs occupy an important place (Table 1). If these conditions are considered as a a number may all provoke dyskinesias. group, Classification depends on observation of the clinical of common chemical and pharmacological charac- features of the abnormal movement, but associated signs teristics emerge. rare when is ad- that must be looked for include dementia, dysarthria, Chorea is excessively levodopa ministered to the normal whereas between 30 posture and gait abnormalities, and reflex changes. subject, and 50 cent of with Parkinson's disease Kayser-Fleischer rings are obviously essential in the per patients diagnosis of neurological Wilson's disease but liver failure develop abnormal movements within two years of the onset of treatment. This observation from other causes may present with abnormal in- levodopa might voluntary movements. suggest that other changes in the Parkinsonian brain are to In However, in the majority of patients it is the abnormal necessary for levodopa produce chorea. Hun- disease exacerbates the chorea and movement that constitutes the only significant finding, so tington's levodopa there are in the brain. that diagnosis and appropriate investigation depends on widespread 'degenerative' changes Patients the facial and buccal chorea of classifying the abnormal movement or dyskinesia. It is developing tardive et often helpful to consider at this stage whether the phenothiazine dyskinesia (Sigwald al., 1959) with dyskinesia is characteristic or recognisable. If not, the almost invariably have brain damage dementia and question should always be asked: 'Could the patient be frequently have undergone leucotomy. Similarly, in making the movement voluntarily and if so why?' Where the movement disorder is voluntarily produced the cause of the disease still remains to be determined; that is, the psychiatric abnormality must be diagnosed and treated Table 1. Causes of chorea. effectively. The problems of treatment in such cases are Drugs but, disturbance is very great fortunately, psychiatric Levodopa (with or without decarboxylase inhibitor) only exceptionally the cause of dyskinesias and the Phenothiazines majority of these conditions are entirely organic in their Butyrophenones pathogenesis. It is therefore unwise to conclude too Oral contraceptives readily that the disorder is due to psychological causes. Phenytoin Finally, it is useful in the diagnosis of an unusual Chorea dyskinesia to decide whether there is any associated Huntington's disturbance of muscle tone. In the and general, dystonias Associated with other diseases Parkinsonian states are associated with hypertonia Sydenham's chorea whereas in and chorea muscle tone is normal myoclonus Chorea gravidarum