Adult-onset focal dystonias: presentation and treatment options.

Adult-onset focal dystonias (AFD) are common disorders that are often misdiagnosed and incorrectly treated. Their presentation is readily recognized, and botulinum toxin has become the agent of choice for treating these disorders. Most of the focal dystonias include cervical dystonia, blepharospasm, oromandibular dystonia, spasmodic dysphonia, and limb dystonia, specifically writer's cramp. Their onset is either idiopathic, familial, or post-traumatic, and the pathophysiology of the focal dystonias is not currently known. Local injections of botulinum toxin into the affected area result in chemical denervation of the muscle, resulting in a weakness of the muscles that are involved in the sustained contractions. This weakness alleviates the painful contraction of the dystonia. In this paper we present a case study of the most common type of focal dystonia, cervical dystonia. The etiology in this case was post-traumatic, and significant improvement resulted after treatment with botulinum toxin type A.