Orthostatic tremor: unsteadiness while standing still
St. Antonius Ziekenhuis, afd. Klinische neurofysiologie, Nieuwegein/Utrecht.
We present three patients with histories of the typical unsteady feeling in the legs while standing still which disappears when walking or sitting down. An orthostatic tremor is a disorder that is difficult to recognise because patients describe balance disturbances rather than tremors. Clinical findings include a fine tremor in the legs which may be invisible but can be heard on auscultation and felt on palpation of the leg muscles. The diagnosis is confirmed by EMG which reveals a pathognomonic tremor of 13-18 Hz while the patient is standing upright. Its pathophysiology is unknown but a disorder related to proprioceptive feedback has been suggested. The tremor can be associated with Parkinson's disease, Graves' disease, and cerebellar or pontine lesions which should be excluded by laboratory investigations and MRI. There is little evidence available on effective treatments, but clonazepam seems to be the first drug of choice, followed by gabapentin. Levodopa can be tried in patients with parkinsonism.
- [PubMed - indexed for MEDLINE]