Rationale:
Paroxysmal kinesigenic dyskinesia (PKD) is a rare movement disorder that presents with sudden episodic attacks of choreoathetosis or dystonia triggered by voluntary movement. PKD can occur alongside focal epilepsy, complicating diagnosis and treatment. This case report describes a female patient with PKD and co-existing focal epilepsy with positive response to lacosamide.
Methods:
Case Presentation: A 31-year-old female presented with a history of episodic abnormal movements starting at age 14. Initially, she developed episodic left lower extremity stiffness triggered by standing, which gradually progressed to involve the left upper extremity. Movements were characterized by left knee extension and toe inversion and left arm extension and pronation. These events occurred in clusters, lasting 2 to 8 weeks, often accompanied by nocturnal spells lasting 5 to 20 seconds. These nocturnal episodes included dystonic twisting and ballistic movements.
The patient began experiencing new nocturnal episodes of left-sided tonic activity evolving into generalized tonic-clonic seizures, accompanied by loss of consciousness and tongue biting. She was evaluated in an Epilepsy Monitoring Unit (EMU), where one clinical seizure was recorded. This seizure involved tonic posturing of the left upper extremity, leftward head turning, and loss of consciousness. Ictal electroencephalogram (EEG) revealed rhythmic theta activity, while interictal EEG showed sharp waves in both the right and left temporal regions. Several typical PKD episodes were also captured, with no electrographic correlate.
Results:
Lacosamide was initiated and resulted in significant improvement in both nocturnal seizures and daytime PKD symptoms. Currently, the patient has been free from nocturnal generalized tonic-clonic seizures for more than one year. Overall, lacosamide helped to reduce the frequency of both types of events.
Conclusions:
This case highlights the challenges in managing patients with co-existing PKD and focal epilepsy, particularly in distinguishing between movement disorders and epileptic seizures. The positive response to lacosamide suggests it may be an effective treatment option for patients with both PKD and focal epilepsy. The underlying mechanisms that make lacosamide effective in this case warrant further investigation. This case contributes to the growing body of evidence supporting the efficacy of lacosamide in managing complex movement disorders with concurrent epilepsy.
Funding: None