Levodopa may improve orthostatic tremor: case report and trial of treatment.

Primary orthostatic tremor is a regular fast lower limb tremor causing unsteadiness on standing. Treatment is generally unsatisfactory. A patient with primary orthostatic tremor who 9 years later developed levodopa responsive idiopathic Parkinson's disease is described. The patient exhibited the classic features of primary orthostatic tremor with relief of the tremor by walking or sitting while treated with levodopa. However, in the "off" state, when the benefits of levodopa disappeared, this orthostatic tremor was continuous and severely compromised the patient's gait. On the basis of this finding eight patients with primary orthostatic tremor were treated with levodopa. Five patients experienced benefit and elected to remain on long term treatment. This study is the first trial of therapy in primary orthostatic tremor and suggests that levodopa can lead to good symptomatic relief in this potentially disabling condition.