neurologic disorders
Dystonias
Treatment of Dystonias
For generalized dystonia, anticholinergic drugs, muscle relaxants, or both For focal or segmental dystonia, botulinum toxin injections to paralyze muscles Sometimes a neurosurgical procedure Forgeneralized dystonia,an anticholinergic drug (trihexyphenidyl2 to 10 mg orally 3 times a day,benztropine3 to 15 mg orally once a day) is most commonly used; the dose is slowly titrated to target. A muscle relaxant (usuallybaclofen), a benzodiazepine (eg,clonazepam), or both may provide adjunctive benefit. Generalized dystonia that is severe or does not respond to drugs may be treated with deep brain stimulation of the globus pallidus interna (GPi), a stereotactic neurosurgical procedure. In some cases, stereotactic unilateral ablative surgery of the GPi is indicated. Forfocal or segmental dystonias or for generalized dystonia that affects mainly one body part,the treatment of choice is Purified botulinum toxin type A or B injected into the affected muscles, done with or without electromyographic guidance and by an experienced practitioner Botulinum toxin weakens excessive muscular contractions through chemodenervation, but it does not alter the abnormal brain circuitry that causes dystonia. Toxin injection is most effective for blepharospasm and torticollis but can be very effective for most other forms of focal dystonia. Dosage varies greatly. Treatments must be repeated every 3 to 4 months because the toxin's duration of activity is limited. Repeating injections before the 3 months have elapsed may cause antibodies against botulinum toxin to develop and thus lessen the toxin's benefit. In some patients, repeated injections, even with dosing intervals > 3 months, cause antibodies against the toxin to develop. However, not all of these antibodies neutralize botulinum toxin. 