Blepharospasm

Botulinum toxin has become the initial treatment of choice for the management of essential blepharospasm, hemifacial spasm and other craniocervical dystonias. Numerous studies have confirmed a 90% to 95% response rate. Although a number of common side effects have been reported, the occurrence and incidence of rare local complications remains poorly understood. More importantly, the acute and chronic distant effects of botulinum toxin have not been clearly elucidated. A better understanding of such effects is essential if clinicians are to appropriately advise patients on the use of this therapeutic modality. This article is based on the Duke University experience in the management of over 500 patients with craniocervical spasm disorders, combined with a review of the published literature. These disorders include essential blepharospasm, oromandibular dystonia, hemifacial spasm, and torticollis. The incidence of side effects following more than 6000 treatments with botulinum toxin i...

To evaluate the long-term effect of botulinum toxin type A (BTX) in the treatment of blepharospasm, a retrospective analysis was conducted from the patients seen at the Movement Disorders Clinic of the Department of Neurology, Hospital das Clínicas, University of São Paulo School of Medicine from 1993 to 2003. A total of 379 treatments with BTX were administered to 30 patients with blepharospasm. Sixty six per cent of the subjects had used oral medication for dystonia and only 15% of them reported satisfactory response to this treatment. Ninety three per cent of the patients showed significant improvement after the first BTX injection. There was no decrement in response when compared the first and the last injection recorded. Adverse effects, mostly minor, developed at least once in 53% of patients. Six patients (20%) discontinued the treatment but there was no case of secondary resistance.

Animal models indicate that the abnormal movements of focal dystonia result from disordered sensorimotor integration. Sensorimotor integration involves a comparison of sensory information resulting from a movement with the sensory information expected from the movement. Unanticipated sensory signals identified by sensorimotor processing serve as signals to modify the ongoing movement or the planning for subsequent movements. Normally, this process is an effective mechanism to modify neural commands for ongoing movement or for movement planning. Animal models of the focal dystonias spasmodic torticollis, writer's cramp, and benign essential blepharospasm reveal different dysfunctions of sensorimotor integration through which dystonia can arise. Animal models of spasmodic torticollis demonstrate that modifications in a variety of regions are capable of creating abnormal head postures. These data indicate that disruption of neural signals in one structure may mutate the activity pa...

Purified botulinum A exotoxin was used in the treatment of forty seven patients with benign essential blepharospasm, 11 patients with hemifacial spasm and 2 patients with age-related entropion. The treatment was effective in all three groups for an average of 3-4 months when symptoms recurred and repeated chemodenervation with toxin was needed. The commonest complication was transient ptosis with an overall frequency of 7.8%. This incidence increased to 11.1% with toxin doses higher than 25 units per orbicularis. The treatment was well accepted by the patients, who were subsequently able to return to pre-blepharospasm lifestyles.