Unilateral lower limb rest tremor is not necessarily a presenting symptom of Parkinson's disease.

Lower leg rest tremor is an uncommon symptom of neurological disease. Review of the files of 16 patients who presented with lower leg tremor (average age 58 +/- 16 years; average disease duration 6.8 +/- 8.5 years) yielded a diagnosis of Parkinson's disease (PD) in 5 and probable multiple system atrophy (MSA) in 3. In 4 patients with an indeterminate diagnosis, cardiac MIBG SPECT was positive in 3, indicating PD, and negative in one, suggesting MSA. Two patients each had psychogenic tremor and drug-induced parkinsonism. Although lower leg tremor is considered an unusual presentation of PD, it should raise suspicions of MSA and other neurodegenerative disorders.