A 17-year-old boy was referred to us with episodic abnormal posturing of all four limbs, neck, trunk, and face without loss of consciousness for the last 3 years [Video 1]. These episodes were precipitated by sudden movement and lasted for 15–20 s. Sudden standing after prolonged sitting and running were the activities that precipitated these abnormal episodes. Hyperventilation and sudden noise were not associated with these episodes. The patient had 30–40 such episodes each day. There was no history of preceding aura, confusion following the episodes, bowel and bladder incontinence, or tongue biting. Past history, birth history, and family history were not significant. Physical examination was normal. For these complaints, he had consulted different physicians. He was diagnosed to be having a psychogenic movement disorder and put on antidepressants but without any relief.
We considered the possibility of paroxysmal kinesigenic dyskinesia (PKD) due to the abnormal episodes of dystonic posturing preceded by the occurrence of sudden movement every time, without loss of consciousness. Computed tomography (CT) of the brain and electroencephalography were done, which were normal. His routine hematological and biochemical investigations were also normal. The patient was put on carbamazepine; after 15 days, when the patient reported back to us, he was completely relieved of his symptoms.
PKD is a rare movement disorder with a prevalence of one per 150,000 according to western literature; however, its prevalence in India is not known. It typically occurs in the 6 month to 40 year age group with a male preponderance and comprises abnormal episodes of dystonic or choreodystonic movement of the body parts precipitated by sudden movements, lasting for less than a minute and without any loss of consciousness. The episode may not occur every time as prolonged rest followed by sudden movement is usually required to precipitate the event. Hence, in clinic, it is important to make the patient sit for a while before evaluating for PKD, otherwise one may miss the event. The frequency of such an episode varies from 100 per day to less than 1 per month.