Use of lamotrigine to treat paroxysmal kinesigenic choreoathetosis

PRRT2-positive self-limited infantile epilepsy: Initial seizure characteristics and response to sodium channel blockers

OBJECTIVE

Self-limited infantile epilepsy (SeLIE) has distinctive clinical features, and the PRRT2 gene is known to be a considerable genetic cause. There have been a few studies on PRRT2-positive SeLIE only, and anti-seizure medications are often required due to frequent seizures at initial seizure onset. This study aimed to provide clinical information for the early recognition of patients with PRRT2-positive SeLIE and to propose effective anti-seizure medications for seizure control.

METHODS

We retrospectively reviewed 36 patients diagnosed with SeLIE with genetically confirmed pathogenic variants of PRRT2. In addition, six atypical cases with neonatal-onset seizures and unremitting after 3 years of age were included to understand the expanded clinical spectrum of PRRT2-related epilepsy. We analyzed the initial presentation, clinical course, and seizure control response to anti-seizure medications.

RESULTS

Patients with PRRT2-related epilepsy had characteristic seizure semiology at the initial presentation, including all afebrile, clustered (n = 23, 63.9%), short-duration (n = 33, 91.7%), and bilateral tonic-clonic seizures (n = 26, 72.2%). Genetic analysis revealed that c. 649dupC was the most common variant, and six patients had a 16p11.2 microdeletion containing the PRRT2 gene. One-third of the patients were sporadic cases without a family history of epilepsy or paroxysmal movement disorders. In the 33 patients treated with anti-seizure medications, sodium channel blockers, such as carbamazepine, were the most effective in seizure control.

SIGNIFICANCE

Our results delineated the clinical characteristics of PRRT2-positive SeLIE, differentiating it from other genetic infantile epilepsies and discovered the effective anti-seizure medications for initial clustered seizure control. If afebrile bilateral tonic-clonic seizures develop in a normally developed infant as a clustered pattern, PRRT2-positive SeLIE should be considered as a possible diagnosis, and sodium channel blockers should be administered as the first medication for seizure control.

Medical treatment of dystonia

Therapeutic strategies in dystonia have evolved considerably in the past few decades. Three major treatment modalities include oral medications, botulinum toxin injections and surgical therapies, particularly deep brain stimulation. Although there has been a tremendous interest in the later two modalities, there are relatively few recent reviews of oral treatment. We review the medical treatment of dystonia, focusing on three major neurotransmitter systems: cholinergic, GABAergic and dopaminergic. We also provide a practical guide to medication selection, therapeutic strategy and unmet needs.

Lamotrigine monotherapy for paroxysmal kinesigenic dyskinesia in children

PURPOSE

To evaluate the efficacy and tolerability of lamotrigine monotherapy in children with paroxysmal kinesigenic dyskinesia.

METHOD

A sample of eighteen children aged between 2 years old and 13 years old who fulfilled the diagnostic criteria from January 2008 to December 2014 was enrolled, they received video electroencephalography, brain image scans and proline-rich transmembrane protein 2 genetic tests. Children with known or suspected diseases which would cause secondary paroxysmal kinesigenic dyskinesia were excluded. The initial dosage of lamotrigine was 6.25 mg, and it was gradually increased every week until attacks were controlled. Patients entered the maintenance dose phase upon reaching the effective dosage, and by being attack free at two consecutive outpatient visits. They were followed up for a couple of years until December 2014.

RESULTS

By the end of the 4th week, the attack-free rate reached 100% among all the patients. During the maintenance dose phase, 16 patients remained attack free, 2 patients received additional drug due to attack relapses when they entered puberty. Three patients had relapses because of non-compliance to the therapy, but they became attack free as soon as they re-started the medicine. The mean daily dosage was 26.4 mg (range 6.25-50). Definite adverse effect related to the drug was not reported in follow up.

CONCLUSION

LTG monotherapy is effective and well tolerated for PKD in children.

Oxcarbazepine-responsive paroxysmal kinesigenic dyskinesia in Wilson disease

A 22-year-old man presented with a 2-year history of tremor of the upper limbs associated to behavioral disorders. A magnetic resonance imaging of the brain showed hyperintensity in the right frontoparietal region, basal ganglia, particularly in the caudate nucleus, midbrain, and pons in T2 sequences, fluid-attenuated inversion recovery, and diffusion. Serum ceruloplasmin levels were 4 mg/dL (range, 20-45 mg/dL), and 24-hour urine cooper excretion was increased up to 223 µg (10-40 µg/24 hours). Slit lamp examination demonstrated the presence of a Kayser-Fleischer ring and penicillamine treatment started. Four months later, he developed episodes of paroxysmal dystonic posturing of his left arm, which increased in frequency reaching 2 or 3 attacks per hour. They were triggered by voluntary movements and forced him to adopt an abnormal flexion of the left forearm over the left bicep and were preceded by a tightening sensation of the left forearm muscles. Episodes completely remitted with oxcarbazepine.

Nonepileptic uses of antiepileptic drugs in children and adolescents

Antiepileptic drugs are often prescribed for nonepileptic neurologic and psychiatric conditions. The United States Food and Drug Administration has approved several antiepileptic drugs for the treatment of neuropathic pain, migraine, and mania in adults. For pediatric patients, use of antiepileptic drugs for non-seizure-related purposes is supported mainly by adult studies, open-label trials, and case reports. Summarized here is the published literature for or against the use of antiepileptic drugs for neuropathic pain, migraine, movement disorders, bipolar disorder, aggressive behavior, and pervasive developmental disorders in children and adolescents. Using the American Academy of Neurology's four-tiered classification scheme for a therapeutic article and translation to a recommendation rating, there are no nonepileptic disorders for which antiepileptic drugs have been established as effective for pediatric patients. Valproate and carbamazepine are "possibly effective" in the treatment of Sydenham chorea, and valproate is "probably effective" in decreasing aggressive behavior. Carbamazepine is "probably ineffective" in the treatment of aggression, and lamotrigine is "possibly ineffective" in improving the core symptom of pervasive developmental disorders. Despite the frequent use of antiepileptic drugs in the treatment of juvenile bipolar disorder, migraine, and neuropathic pain, the data are insufficient to make recommendations regarding the efficacy of antiepileptics in these conditions in children and adolescents.

Topiramate therapy for paroxysmal kinesigenic choreoathetosis

We observed the clinical efficacy of topiramate for paroxysmal kinesigenic choreoathetosis (PKC). Topiramate was administered as a monotherapy with titrated dosages to 8 patients with PKC. Target daily dose of topiramate was 100 to 200 mg; the follow-up period ranged from 8 months to 2 years. All of the patients became attack-free, and side effects were mild. The results show that topiramate is effective as a monotherapy for treating patients with PKC. The response to topiramate indicates that the disease may be caused by an ion channel defect.

Paroxysmal kinesigenic dyskinesias

The paroxysmal dyskinesias (PxDs) are involuntary, intermittent movement disorders manifested by dystonia, chorea, athetosis, ballismus or any combination of these hyperkinetic disorders. Paroxysmal kinesigenic dyskinesia (PKD), one of the four main types of PxD, involves sudden attacks of dyskinesias induced by voluntary movements. PKD most commonly occurs sporadically or as an autosomal-dominant familial trait with variable penetrance. Many causes of secondary PKD are being recognized. The exact pathophysiology of the PxDs awaits further elucidation, although basal ganglia dysfunction appears to play a major role. Although the precise gene remains unknown, genetic linkage studies have isolated loci on chromosome 16, which colocalizes with the locus for familial infantile convulsions and paroxysmal choreoathetosis in some studies. The episodic nature of PKD and its relationship with other episodic diseases, such as epilepsy, migraine, and episodic ataxia, suggests channelopathy as a possible underlying etiology. PKD may remit spontaneously, but it also responds well to anticonvulsants as well as some other agents.

Paroxysmal Dyskinesia

This group of disorders is characterized by periodic sudden events of involuntary movement. The clinical range of these involuntary movements is wide including tonic spasms, choreiform and athetoid movements and sustained dystonic postures. Confusion with reflex forms of epilepsy has been common in the past, but in general, paroxysmal dyskinesias are not associated with alterations in consciousness or epileptiform activity on electroencephalogram. The underlying basis of the paroxysmal dyskinesia is under active investigation as is their relationship to epilepsy and other paroxysmal disorders.