The occurrence of ballism-chorea and dystonia implies development of lesions involving the basal ganglia and their afferent or efferent connections, such as thalamus, subthalamic nucleus, basal ganglia, and putamen. However, the unique feature of this patient is choreic movement without responsible brain lesions. The flinging movement of her right arm and forearm even resembled ballism. Ballism has never been reported in spinal cord lesions whereas chorea has been seen very rarely.
4 It was uncertain whether she exhibited a pure ballism or chorea but presumably it is not important. While ballism and chorea are distinguishable based upon the type and distribution of movements, they may represent two different symptoms or a spectrum of the same basic disease processes.
5 Why a patient with a spinal cord lesion develops chorea but not ballism is unknown. Ballism, a coarse proximal movement, could evolve into more distal and lower amplitude chorea. Athetosis, which is considered a slow form of chorea, often evolves further into dystonia.
5 Why movement disorders occur in only a minority of patients with myelopathy is also unknown. A number of different mechanisms have been suggested, but were poorly understood. One mechanism involves the posterolateral cervical cord, the projections from supraspinal centers on the Ia inhibitory neurons, and other interneurons concerned with reciprocal inhibition.
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3 Disruption of the somatosensory pathways or motor cortex to the striatum also may produce abnormal movement without sensory loss.
1 For our purposes, considering paroxysmal chorea and dystonia together as involuntary movements, we can infer the effect of provocative movements in this patient from the results of previous studies. Paroxysmal chorea could be easily provoked by movement, either passive or volitional, and by tactile stimulation.
4 It often crosses to the contralateral trunk or limbs. The so called trigger zone was found at either the same spinal segment or below the clinically estimated segment.
Although this patient had relapsing-remitting weakness, it did not fulfill the conditions of definite NMO when the involuntary movements occurred. However, she must have had NMO, considering the visual symptoms afterwards. Despite the lack of lesions located appropriately for the involuntary movements, steroid therapy was suggested in relapsing-remitting NMO. However, we could not evaluate the effectiveness of such therapy because our patient was treated with steroid and clonazepam.
Movement disorders associated with multiple sclerosis or NMO are rare. Our case suggests that ballism-chorea could present in a spinal cord lesion without involvement of striatum and deep sensory abnormalities. Thus, acute exacerbation of recurrent myelopathy in NMO may be associated with transient movement disorders.