When evaluating episodic abnormal movements, identifying the precise trigger and duration is essential to making the correct diagnosis. Paroxysmal dyskinesias are broadly categorized based on what precipitates the attack:
1. Paroxysmal Kinesigenic Dyskinesia (PKD)
Trigger: Sudden voluntary movement or startle.
Duration: Seconds to minutes.
Key Gene: PRRT2.
First-line Therapy: Anticonvulsants (Carbamazepine, Phenytoin).
2. Paroxysmal Nonkinesigenic Dyskinesia (PNKD)
Trigger: Alcohol, caffeine, fatigue, or stress.
Duration: Minutes to hours.
Key Gene: PNKD (formerly MR-1).
First-line Therapy: Benzodiazepines (Clonazepam, Diazepam).
3. Paroxysmal Exertion-Induced Dyskinesia (PED)
Trigger: Prolonged exercise or physical exertion (e.g., walking, running).
Duration: 5 to 30 minutes.
Key Gene: SLC2A1 (GLUT1 deficiency).
First-line Therapy: Ketogenic diet, avoidance of prolonged exertion, or acetazolamide.
