Paroxysmal kinesigenic choreoathetosis or dystonia.
Incidence
It is inherited as an autosomal dominant trait in 75% of cases. The rest can be due to mutations. Males are affected more than females.
Clinical Characteristics
Paroxysmal kinesigenic choreoathetosis or dystonia usually starts in childhood and is inherited as an autosomal dominant trait in 75% of cases. The rest can be due to mutations. Males are affected more than females. Attacks of involuntary movements affecting limbs comform the classical definition of dystonia, choreoathetosis, chorea or even balismus. They are brief, lasting a few seconds to five minutes or more. They are initiated by movements (that is why it is called kinesigenic) or upon being startled, especially after a period of rest. They may be unilateral or bilateral. Speech may be impossible but consciousness always remain normal. Sometimes the attacks are preceded by brief sensory aura confined to the affected limb. The attack is followed by a brief refractory period. The episodes may occur up to 100 times a day. Between attacks the child is normal. EEG and brain MRI is normal. Treatment with anticonvulsant drugs such as Dilantin or Tegretol may prevent the attacks, but some cases are resistant to all known agents. The paroxysmal episodes tends to subside with age.
Precipitants
The extrapyramidal movements are initiated by movements (that is why it is called kinesigenic) or upon being startled, especially after a period of rest.
Provocation Tests
The extrapyramidal movements are initiated by movements (that is why it is called kinesigenic) or upon being startled, especially after a period of rest.
Diagnostic Procedures
EEG and brain MRI is normal. It is a clinical diagnosis. Keep in mind that if patient has developmental delay and microcephaly, it may be a GLUT1 gene mutation.