Focal and Segmental Dystonias
For most patients with focal and segmental dystonia, the treatment of choice is BTX. Although BTX is the treatment of choice, it typically is not provided at the first clinic visit. Instead, the first visit is used to complete diagnostic testing if needed, to provide counseling regarding expectations, to plan the doses and procedure required, and to obtain insurance approvals for the procedure. In the interval between the initial visit and the BTX procedure, a trial of at least one oral agent often can be initiated. Finding an oral agent with at least partial efficacy can be useful as adjunctive therapy or for times when symptoms flare up between BTX treatments. The selection of oral agents for empirical trials is guided by the type of dystonia, and anticipated side effects in relation to the patient’s age and other potential comorbidities.
- Cervical Dystonia
For cervical dystonia, the initial choice for an adjunctive oral agent often is trihexyphenidyl. A benzodiazepine can be added if tremor is prominent, and some patients also benefit from a muscle relaxant. BTX alone, or combined with one adjunctive oral agent, suffices for the vast majority of patients. If combined treatment is inadequate or resistance to BTX develops, selective denervation or DBS can be considered. As for any surgical procedure, patient selection and counseling is critical for success.
- Blepharospasm and Other Lower Facial Dystonias
For blepharospasm and other lower facial dystonias, a benzodiazepine provides a good initial choice for an adjunctive agent with BTX. Trihexyphenidyl is a second choice. However, BTX alone provides sufficient relief for the majority of these patients, so adjunctive oral medications often are not needed. Myectomy may be offered to those who do not respond to medical therapy.
- The Limb Dystonias
The limb dystonias are among the most challenging of the focal dystonias to treat with BTX. BTX can be useful, but it is more difficult to obtain satisfactory results than in cervical and craniofacial dystonias. For limb dystonias of children and limb dystonias that are not task-specific in adults, a good initial choice is levodopa, followed by trihexyphenidyl. A benzodiazepine is useful if tremor is prominent. The adult-onset focal dystonias do not often respond to levodopa, so trihexyphenidyl and benzodiazepines are often used.
For patients with generalized dystonia, it is not feasible to target all involved body regions with BTX. Instead, the primary treatment modality involves oral medications. Generally, successive trials of oral agents are conducted with levodopa, trihexyphenidyl, baclofen, and sometimes other drugs. Although BTX may not be useful for comprehensive treatment of many generalized dystonias, it may be quite useful for treating the most discomforting aspects of a generalized dystonia. When medical therapy appears inadequate, more invasive approaches involving intrathecal baclofen or DBS are considered. As for any surgical procedure, patient selection is very important. Some generalized dystonias respond better to surgery than others, and some patients may not be good surgical candidates because of other comorbidities. Although these procedures are offered by many neurosurgeons, the best outcomes are likely to be achieved by those who are more experienced, and particularly those who work at centers with multidisciplinary teams.
H. A. Jinnah, MD PhD
Emory University School of Medicine
Atlanta, GA 30307