Botulinum toxin in the management of dystonia.

Dystonia is a neurologic disorder that can occur at any age and often results in significant disability. The therapeutic application of botulinum toxin has revolutionized the treatment of this disorder, particularly for the adult-onset focal forms such as cervical dystonia and blepharospasm. The two available commercial preparations, botulinum toxin types A and B, have been shown to be equally efficacious in cervical dystonia and are both reasonable first-line choices for treating other forms of focal dystonia. Preliminary studies have suggested that differences in tolerability and immunogenicity may exist between the two preparations, but this has not been adequately evaluated. Because of high cost, complicated administration, potentially serious side effects, and the risk of developing immunoresistance, this treatment should be administered only by a physician with sufficient background in the diagnosis and treatment of dystonia, to ensure optimal outcomes.