Circadian rhythm sleep disorder associated with pontine lesion

Unlabeled uses of botulinum toxins: a review, part 1

PURPOSE

Efficacy and safety data regarding the unlabeled uses of botulinum toxins are reviewed, and the pharmacology, adverse effects, and characteristics of commercially available botulinum toxins are discussed.

SUMMARY

More than 300 articles have been published on the use of botulinum toxins, particularly botulinum toxin type A, to treat conditions characterized by excessive smooth or skeletal muscle spasticity. Botulinum toxins are synthesized by Clostridium botulinum and cause temporary local paralysis of the injected muscle by inhibiting acetylcholine release at the neuromuscular junction. While botulinum toxins have Food and Drug Administration-approved labeling to treat a limited number of spasticity disorders, including cervical dystonia and blepharospasm, the toxins have more than 50 reported therapeutic uses. Among these uses, the most rigorously studied indications include achalasia, essential tremors, palmar hyperhidrosis, chronic anal fissures, headache prophylaxis, and limb spasticity. The main adverse effects of the toxins are pain and erythema at the injection site, although unintended paralysis of muscles adjacent to the site of toxin injection may also occur.

CONCLUSION

Clinical studies support the use of botulinum toxins for certain conditions, although more studies are needed to establish the role of the drug relative to conventional therapies and to determine patient predictors of response. Although botulinum toxins are generally well tolerated, a patient-specific risk-benefit assessment should precede any decision to use them for unlabeled indications.

Treatment of Chronic Refractory Intractable Headache with Botulinum Toxin Type A: A Retrospective Study

Chronic refractory daily headache is a relatively common problem in the Australian population. Several million working hours per year are lost due to this illness. Generally not responding to conventional therapies. We treated 22 such patients diagnosed as severe refractory migraine and/or mixed tension headache at our multidisciplinary pain management center. Before inclusion to our study, they received maximal medical management, which included cognitive behavior therapy, but failed to respond. These patients received between 30 and 100 units of botulinum toxin type A. Our study showed 84% (19 of 22) achieved significant improvement in their pain complaint. There was significant reduction of medications particularly opioids. The duration of pain relief ranged from 1 to 6 months. Repeat injections were necessary in several of the patients. There were minor complications but these reversed spontaneously without further treatment.

Pathophysiology of chronic daily headache

Despite no clear explanation of the mechanism underlying chronic daily headache, sensitization of central nociceptive neurons is one possibility. Either prolonged activation of peripheral nociceptors or any factors that can alter the endogenous pain control system can trigger this process. A decrease in platelet serotonin has been observed in patients with chronic tension-type headache as well as migraine patients with medication-induced headache. It was also shown that chronic analgesic exposure led to changes in the serotonin content and the density of the 5-HT(2A) receptor in the cerebral cortex. The plasticity of the serotonin-dependent pain control system may facilitate the process of sensitization and results in the development of chronic daily headache.

Treatment of relative sialorrhoea with botulinum toxin type A: description and rationale for an injection procedure with case report

This paper describes a technique for treatment of relative sialorrhoea by injection of botulinum toxin type A. It includes the rationale for treatment, a description of the regional anatomy, the physiological basis for treatment and the applied pharmacology of the drug. Included also is a case report which is intended to provide an illustration of the benefits of using this method for treating this condition.

Side-effects of intradermal injections of botulinum A toxin in the treatment of palmar hyperhidrosis: a neurophysiological study

Focal palmar hyperhidrosis can be effectively abolished by intradermal injections with botulinum toxin. Muscle weakness of finger grip has been reported as a reversible side-effect of this new treatment. The objective of this work was to measure muscular side-effects after treatment of palmar hyperhidrosis with botulinum toxin. As botulinum toxin has been used in the treatment of pain, we studied whether the toxin might influence afferent thin-fibre function by measuring temperature perception thresholds. Thirty-seven patients treated with botulinum toxin (Botox, Allergan Pharmaceuticals, Irvine, CA, USA) showed a decrease in compound muscle action potential (CMAP) for both abductor pollicis brevis (APB) and abductor digiti minimi (ADM) compared with pre-injection values on average by 64 and 36%, respectively, at 3 weeks which returned nearly to normal at 37 weeks. Muscle power for both finger abduction and finger opposition decreased to a lesser extent. Repetitive nerve stimulation and single fibre electromyography (EMG) showed a disturbed neuromuscular transmission. Thus, despite careful technique with small doses of botulinum toxin injected intradermally, the toxin diffuses to underlying muscles. With regard to the present results, one should be careful in using higher doses of Botox than 0.8 mU/cm(2) in the palmar skin above intrinsic muscles. No influence on thin-fibre function was seen.