B Chan, KY Chan

Abstract

Objective: To investigate the clinical characteristics and treatment outcome of idiopathic paroxysmal kinesigenic dyskinesia (PKD) in Chinese paediatric patients. Method: This was a retrospective study of thirteen patients with a diagnosis of idiopathic paroxysmal kinesigenic dyskinesia that was followed up at a regional hospital between 2003 and 2008. Results: A total of thirteen patients with idiopathic PKD were reviewed, all were Chinese. Six patients (46%) had a positive family history of PKD. The male-to-female ratio was 3.3:1, and a higher male preponderance rate of 6:1 was noted among the sporadic cases. Ten patients (77%) presented with dystonic attacks. All cases were initially diagnosed as other medical conditions such as focal epilepsy, motor tics, muscle spasm or psychogenic disorder. Response to low dose carbamazepine (100-200 mg daily) was excellent among the treated patients. The exact pathophysiologic mechanism in PKD was not well documented, and it was postulated that basal ganglia dysfunction or mutation in central nervous system ion channels were the major ones causing this paroxysmal disorder. Conclusion: The clinical characteristics of childhood idiopathic paroxysmal kinesigenic dyskinesia in the Chinese population are very similar to previous published data, with the exception that in our study, a higher male to female ratio and a higher proportion of patients with initial presentation of dystonia are noted. Clinicians often encounter difficulty in recognising and diagnosing the disorder in the local setting. There is a need to enhance the medical professionals' awareness of this disorder in which treatment is highly effective and misdiagnosis will either delay treatment or put patients on unnecessary investigations. Early referral to specialist is advisable.