Potassium channel blocker 4-aminopyridine is effective in interictal cerebellar symptoms in episodic ataxia type 2--a video case report.

Episodic ataxia type 2 (EA2) is an autosomal-dominant hereditary disorder clinically characterized by recurrent attacks of vertigo, imbalance and ataxia. Studies have shown that 4-aminopyridine (4-AP) is capable to prevent these attacks. However, there are no reports whether 4-AP is able to attenuate interictal cerebellar ataxia. Using the scale for assessment and rating of ataxia (SARA), we examined the efficacy of 4-AP on interictal ataxia in a 63-year-old female patient who suffered from EA2 since the age of 57. EA2 was diagnosed based on clinical criteria and not genetically proven. When treatment with 4-AP was paused the patient was suffering from marked gait and stance ataxia. After re-initiation of treatment with 5 mg 4-AP t.i.d., there was pronounced improvement in gait and stance ataxia. Within 24 hours SARA score lowered from 8.5 to 4.5 points. We conclude that 4-AP may be beneficial for interictal cerebellar ataxia in late onset EA2. (c) 2008 Movement Disorder Society.