Muscle & nerve. Supplement最新文献

The seven serotypes of botulinum toxin (BTX) produced by Clostridium botulinum exert their paralytic effect by inhibiting acetylcholine release at the neuromuscular junction. Each of these zinc endopeptidases cleaves one or more proteins involved in vesicle transport and membrane fusion. The extent of paralysis depends on both doses and volume; the duration of paralysis is further dependent on the serotype employed. Restoration of neuromuscular function follows axon terminal sprouting. The two major commercial preparations of BTX-A appear to differ in their relative potencies, despite a common unit labeling system. Adverse effects are a consequence of the drug's mechanism of action, and can usually be tolerated or mitigated through dosing changes. Patients who are pregnant or lactating, or who have a neuromuscular disease, may not be appropriate candidates for BTX therapy. Development of resistance to BTX-A therapy, characterized by absence of any beneficial effect and by lack of muscle atrophy following the injection, is an important clinical issue. The incidence of antibody-mediated resistance, as determined by the mouse lethality assay, is reported between 3% and 10%. Use of the smallest possible effective dose and longer treatment intervals may reduce the likelihood of antibody development. Other serotypes may benefit those who have developed antibody resistance.

Spasticity from an upper motor neuron syndrome may cause a variety of symptoms that interfere with function. Decisions regarding spasticity treatment are influenced by the chronicity, severity, and distribution of the spasticity; the locus of injury; the presence and severity of co-morbidities; the availability of support; and the goals of treatment. Not all spasticity can or even should be treated; tone reduction is indicated only if spasticity interferes with some level of function, positioning, care, or comfort. Treatment goals should be well outlined before treatment begins. Botulinum toxin may be used to treat focal spasticity as part of an overall treatment plan.

Cerebral palsy (CP) is characterized by aberrant control of movement or posture and appears early in life secondary to central nervous system damage. The symptoms of CP fall into four groups: symptoms due to loss of selective motor control; symptoms due to abnormal muscle tone; symptoms due to imbalance between muscle agonists and antagonists; and symptoms due to impaired balance. The goals of treatment are to maximize function and minimize the development of joint contracture and other secondary problems. Development of a treatment plan begins with the definition of objectives and consideration of the effects of growth and development on the patient's abilities. The role of botulinum toxin in CP treatment has grown in recent years. The patient who could benefit most from botulinum toxin treatment is one who is hypertonic and whose abnormal muscle tone is interfering with function, or who is expected to develop joint contracture with growth because of this abnormal tone. By altering this muscle tone, function can be enhanced or additional therapeutic modalities can be employed. Assessing treatment outcomes for BTX injection involves the same set of questions and measurements as for other types of treatments and depends on the careful definition of treatment objectives beforehand.