[Clinical symptoms, diagnosis and treatment of focal dystonias].

Focal dystonias are relatively rare and significantly disabling disorders. These include cervical dystonia, blepharospasm and hemifacial spasm. The spasmodic torticollis consists of tonic posturing of the head away from its neutral position or twisting of the cervical muscles. The blepharospasm is an abnormal blinking, eyelid tic or twitch resulting from any cause. The hemifacial spasm is an involuntary unilateral twitching of the facial muscle. Patients affected by focal dystonias are predominantly females, and many times psychical stress can be revealed. The pathogenesis may involve dysfunction of the basal ganglia and brain stem although the exact mechanism remains to be elucidated. The patients need to be diagnosed and treated in centers specialized in movement disorders. Although many drug treatments can be beneficial, the most effective treatment is the local Botulinum toxin injection into the affected muscles. This neurotoxin produces temporary neuromuscular blockade, which reveals the symptoms and pain. The effect of the toxin is temporary and, therefore, the injection needs to be repeated every 6-12 weeks. The most common side effects are hypersensitivity, bleeding, hematoma, ptosis, facial spasm, dysphasia or dysarthria. With the use of proper dose and injection sites these side effects can be avoided.