Paroxysmal kinesigenic choreoathetosis

A neurological disorder characterized by sudden involuntary movements

Paroxysmal kinesigenic choreoathetosis
Synonyms	Familial PKD, Paroxysmal kinesigenic dyskinesia
Pronounce
Field	Neurology, Genetics
Symptoms	Sudden, brief episodes of chorea, athetosis, or dystonia triggered by voluntary movement
Complications	Impaired mobility during attacks, anxiety related to attacks
Onset	Childhood or adolescence
Duration	Chronic, lifelong condition
Types	Primary (familial) or secondary to other disorders
Causes	Mutations in the PRRT2 gene (most commonly)
Risks	Family history of similar movement disorders
Diagnosis	Clinical evaluation, family history, genetic testing
Differential diagnosis	Epilepsy, other paroxysmal dyskinesias, tic disorders
Prevention	Avoiding movement triggers may reduce episodes
Treatment	Anticonvulsants such as carbamazepine or oxcarbazepine
Medication	Carbamazepine, oxcarbazepine, phenytoin
Prognosis	Good with appropriate medication; episodes often decrease with age
Frequency	Rare
Deaths	Not typically life-threatening

Paroxysmal kinesigenic choreoathetosis (PKC), also known as paroxysmal kinesigenic dyskinesia (PKD), is a rare neurological disorder characterized by sudden, involuntary movements triggered by voluntary movement. These episodes are typically brief, lasting seconds to minutes, and can include chorea, athetosis, or dystonia.

Presentation

PKC is marked by episodes of abnormal movements that are often precipitated by sudden voluntary movements, such as standing up or beginning to walk. The episodes can vary in frequency and severity, and they typically last less than a minute. Patients may experience multiple episodes per day. The movements can include:

• Chorea: Rapid, irregular, and unpredictable movements.
• Athetosis: Slow, writhing movements, particularly of the hands and feet.
• Dystonia: Sustained muscle contractions causing twisting and repetitive movements or abnormal postures.

Pathophysiology

The exact cause of PKC is not fully understood, but it is believed to involve dysfunction in the basal ganglia, a group of nuclei in the brain associated with movement control. Genetic factors play a significant role, with several cases linked to mutations in the PRRT2 gene. This gene is involved in synaptic function and neuronal communication.

Diagnosis

Diagnosis of PKC is primarily clinical, based on the characteristic presentation of the disorder. A detailed patient history and neurological examination are essential. Magnetic resonance imaging (MRI) and other neuroimaging techniques are typically normal but may be used to rule out other conditions. Genetic testing can confirm mutations in the PRRT2 gene, supporting the diagnosis.

Management

Management of PKC involves both pharmacological and non-pharmacological approaches. The primary treatment is the use of anticonvulsants, such as carbamazepine or phenytoin, which can significantly reduce the frequency and severity of episodes. Lifestyle modifications, including avoiding known triggers, can also be beneficial.

Prognosis

The prognosis for individuals with PKC is generally favorable, especially with appropriate treatment. Many patients experience a significant reduction in symptoms with medication. The disorder does not typically progress, and life expectancy is normal.

Related pages

• Chorea
• Athetosis
• Dystonia
• Basal ganglia
• PRRT2