Table of Contents

HK J Paediatr (New Series)
Vol 14. No. 4, 2009

HK J Paediatr (New Series) 2009;14:235-242

Original Article

Retrospective Study of Idiopathic Paroxysmal Kinesigenic Dyskinesia in Children: A Rare and Benign Neurological Disorder Commonly Being Misdiagnosed or Overlooked

B Chan, KY Chan


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.

目的:調查並研究中國兒童原發性陣發性動作誘發運動障礙(PKD)病人的臨床特點以及治療預後。方法:根據地區醫院內診斷的13例PKD病人於2003至2008年期間隨診的情況進行回顧性分析。結果:本文共回顧分析了13例患PKD的病人,均為中國人。其中6名病人(46%)有PKD陽性家族史,男女比例為3.3:1。而在散發病例中,男性所佔的比例更高,為6:1。10名病人(77%)臨床表現為肌張力異常發作。所有病例最初均被診斷為其他疾病,例如限局性癲癇、運動抽動、肌肉痙攣或心理源性障礙。從治療反應上看,病人對於中低劑量卡巴咪嗪(每日100-200 mg)反應佳。現在,PKD確切的病理生理機制尚不明確,考慮可能主要是與基底節功能障礙以及中樞神經系統離子通道改變有關。結論:本回顧研究發現在中國兒童人群中,先天性陣發性運動源性運動障礙的臨床特點與其他既往報導相似,但不同之處是發現男性發病率要高於女性,以及最初出現張力失常表現的病人比例較高。通常情況下,臨床醫生對於發現並診斷此病存在困難。因為本病的治療療效佳,誤診不僅會延誤治療還會導致病人接受不必要的檢查,故而需要加強醫務工作者對於本病的認知,並建議將此類病人儘早轉診至專科醫生處。

Keyword : Carbamazepine channelopathies; Epilepsy; Movement disorders; Paroxysmal dyskinesias



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