Runner's dystonia.

Adult-onset focal dystonia in the upper limbs is well characterized whereas such dystonia has been rarely reported in the lower limbs, especially in proximal parts. When such focal dystonia occurs in an athlete it is often wrongly attributed to an orthopedic disorder. We present five cases, three female and two male with mean age of 44.6+/-10.43 years, mean age at onset of 37.4+/-10.33 years, and mean duration of symptoms for 7.2+/-4.44 years, who initially noted dystonia of one leg during long-distance running. The clinical features of dystonia in these long-distance runners overlap with those of more recognizable forms of focal dystonia including relief with sensory or motor "tricks". They also share features with paroxysmal dyskinesia and carbamazepine markedly ameliorated the symptoms at least in one patient. One patient benefited from an oral anticholinergic, one from levodopa, and another two patients benefited from repeat botulinum toxin injections. Our patients differed from the typical childhood-onset leg dystonia, such as the DYT1 dystonia, in that there was no family history of dystonia and the leg dystonia remained focal without spreading to other body parts. Two of our patients had prior injury to the affected leg within 1 year prior to the onset of the dystonia, raising the possibility of peripherally-induced dystonia. We draw attention to this rare, disabling, adult-onset focal dystonia involving proximal lower limbs. When recognized early, it may be treated effectively with either anticholinergic drugs, anticonvulsants, levodopa, or botulinum toxin injections.