Undesirable distant effects following botulinum toxin type a injection

Botulinum toxin A versus microwave thermolysis for primary axillary hyperhidrosis: A randomized controlled trial

Background

Botulinum toxin A (BTX) and microwave thermolysis (MWT) represent 2 treatment modalities for axillary hyperhidrosis with different procedural and efficacy profiles.

Objective

To compare long-term outcomes following BTX vs MWT treatment of axillary hyperhidrosis.

Methods

A prospective, randomized, within-patient, controlled trial, treating axillary hyperhidrosis with contralateral BTX and MWT. Objective sweat measurement and patient-reported outcome measures for sweat and odor were collected at baseline, 6-month and 1-year follow-up (6M/1YFU). Hair reduction and patient treatment preference was also assessed.

Results

Sweat reduction was significant (all P <.01) for both interventions throughout the study. Objectively, sweat reduction was equal at 1-year FU (ΔP =.4282), but greater for BTX than MWT at 6-month FU (ΔP =.0053). Subjective sweat assessment presented comparable efficacy (6MFU: ΔP =.4142, 1YFU: ΔP =.1025). Odor reduction was significant (all P <.01) following both interventions, whereas only sustaining for MWT (6MFU: ΔP =.6826, 1YFU: ΔP =.0098). Long-term, hair reduction was visible after MWT, but not BTX (ΔP ≤.0001), and MWT was preferred by the majority of patients (76%).

Limitations

The intrinsic challenges in efficacy assessment.

Conclusion

This study exhibited BTX and MWT with similar sweat reduction, but distinguishable odor and hair reduction at 1-year FU. These findings support individualized treatment approaches for axillary hyperhidrosis based on patient-specific symptoms and preferences.

The role of botulinum neurotoxin BoNT-A in the management of oily skin and acne vulgaris: A comprehensive review

Oily skin and acne vulgaris are prevalent dermatological conditions with a significant impact on both physical and emotional well-being. Despite numerous available treatments, there is a pressing need for effective, long-term solutions. Botulinum Neurotoxin (BoNT-A) has emerged as a potential therapeutic option. However, existing reviews in this area are often limited. This review aims to comprehensively assess the use of BoNT-A in managing oily skin and acne vulgaris while addressing gaps in previous publications. It integrates the latest research, clinical trials, and case studies to provide an up-to-date analysis of BoNT-A mechanisms of action, efficacy, safety, and long-term outcomes. The review systematically analyzes existing evidence, critically evaluates study strengths and limitations, and explores potential synergies with other treatments. It also examines the safety profile of BoNT-A and its potential long-term effects. This review uncovers promising insights into how BoNT-A affects oily skin and acne vulgaris, including its ability to regulate sebum production, reduce inflammation, and potentially shrink pore size. It provides a comprehensive overview of relevant studies and clinical trials, detailing their methodologies, protocols, measures, and results. Collectively, these studies show significant reductions in sebum production, increased patient satisfaction, and smaller pores following BoNT-A treatment. In conclusion, this review addresses knowledge gaps and provides a comprehensive analysis of BoNT-A as a therapeutic option for oily skin and acne vulgaris. By consolidating evidence and highlighting areas for further investigation, it guides clinicians and researchers toward more effective, personalized treatments for individuals with these dermatological challenges.

A look at the future-new BoNTs and delivery systems in development: What it could mean in the clinic

Despite the expanding clinical utility of botulinum neurotoxins, there remain problems to be solved for attaining the best outcome. The efficacy and safety need to be reconsidered for commercially available preparations all derived from subtype A1 or B1. Emerging new toxins include A2 or A6 subtypes or engineered toxins with less spread, more potency, longer durations of action, less antigenicity and better safety profile than currently used preparations. Non-toxic BoNTs with a few amino acid replacements of the light chain (LC) may have a role as a drug-delivery system if the toxicity is abolished entirely. At present, efficacy of these BoNTs in animal botulism was demonstrated.

Botulinum Toxins for Aesthetic Facial Injections - A scientific review to support evidence-based best practice

Botulinum Toxins (BoNT) are complex biological products. Each licensed BoNTA has its own individual characteristics resulting into different attributes, some of them being of clinical relevance. Besides profound anatomical knowledge and understanding of aesthetic principles, the responsible injecting physician should be aware of those pharmaceutical and clinical properties. Especially against the background of new BoNTA formulations receiving approval by the authorities a critical and dedicated discussion on the individual characteristics should take place and the potential relevance on the treatment outcome should be taken into consideration.

Transient Receptor Potential Channels and Botulinum Neurotoxins in Chronic Pain

Pain afflicts more than 1.5 billion people worldwide, with hundreds of millions suffering from unrelieved chronic pain. Despite widespread recognition of the importance of developing better interventions for the relief of chronic pain, little is known about the mechanisms underlying this condition. However, transient receptor potential (TRP) ion channels in nociceptors have been shown to be essential players in the generation and progression of pain and have attracted the attention of several pharmaceutical companies as therapeutic targets. Unfortunately, TRP channel inhibitors have failed in clinical trials, at least in part due to their thermoregulatory function. Botulinum neurotoxins (BoNTs) have emerged as novel and safe pain therapeutics because of their regulation of exocytosis and pro-nociceptive neurotransmitters. However, it is becoming evident that BoNTs also regulate the expression and function of TRP channels, which may explain their analgesic effects. Here, we summarize the roles of TRP channels in pain, with a particular focus on TRPV1 and TRPA1, their regulation by BoNTs, and briefly discuss the use of BoNTs for the treatment of chronic pain.

Contribution of Single-Fiber Evaluation on Monitoring Outcomes Following Injection of Botulinum Toxin-A: A Narrative Review of the Literature

Botulinum toxin-A (BoNT-A) blocks acetylcholine release at the neuromuscular junction (NMJ) and is widely used for neuromuscular disorders (involuntary spasms, dystonic disorders and spasticity). However, its therapeutic effects are usually measured by clinical scales of questionable validity. Single-fiber electromyography (SFEMG) is a sensitive, validated diagnostic technique for NMJ impairment such as myasthenia. The jitter parameter (µs) represents the variability of interpotential intervals of two muscle fibers from the same motor unit. This narrative review reports SFEMG use in BoNT-A treatment. Twenty-four articles were selected from 175 eligible articles searched in Medline/Pubmed and Cochrane Library from their creation until May 2020. The results showed that jitter is sensitive to early NMJ modifications following BoNT-A injection, with an increase in the early days’ post-injection and a peak between Day 15 and 30, when symptoms diminish or disappear. The reappearance of symptoms accompanies a tendency for a decrease in jitter, but always precedes its normalization, either delayed or nonexistent. Increased jitter is observed in distant muscles from the injection site. No dose effect relationship was demonstrated. SFEMG could help physicians in their therapeutic evaluation according to the pathology considered. More data are needed to consider jitter as a predictor of BoNT-A clinical efficacy.

Jitter Evaluation in Distant and Adjacent Muscles after Botulinum Neurotoxin Type A Injection in 78 Cases

To study the jitter parameters in the distant (DM) and the adjacent muscle (AM) after botulinum neurotoxin type A (BoNT/A) injection in 78 patients, jitter was measured by voluntary activation in DM (n = 43), and in AM (n = 35). Patients were receiving BoNT/A injections as a treatment for movement disorders. Mean age 65.1 years (DM) and 61.9 years (AM). The mean jitter was abnormal in 13.9% (maximum 41.4 µs) of DM, and 40% (maximum 43.7 µs) of AM. Impulse blocking was sparse. We found no correlation of the mean jitter to age, BoNT/A most recent injection (days/units), number of muscles injected, total BoNT/A units summated, number of total BoNT/A sessions, beta-blockers/calcium channel blockers use, and cases with local spread symptoms such as eyelid drop/difficulty swallowing. Maximum mean jitter (41.4/43.7 µs) for DM/AM occurred 61 and 131 days since the most recent BoNT/A, respectively. The far abnormal mean jitter (32.6/36.9 µs) occurred 229 and 313 days since the most recent BoNT/A. We suggested that jitter measurement can be done after BoNT/A in a given muscle other than the injected one, after 8 (DM) and 11 (AM) months, with reference >33 µs and >37 µs, respectively.

Application of botulinum toxin in pregnancy and its impact on female reproductive health

Introduction: Botulinum toxin (BoNT) is a protein secreted by the anaerobic Gram-negative bacterium Clostridium botulinum. Among the seven known subtypes, type A is the most commonly used in women to treat diseases. It primarily blocks presynaptic release of acetylcholine at the neuromuscular junction, resulting in temporary muscle paralysis; thus, it is suitable for treating dystonia and other systemic diseases. BoNT is used widely for treating diseases that persist throughout, and may worsen during, pregnancy, such as cervical dystonia and achalasia. Thus, it is important to investigate whether BoNT injection during pregnancy causes side effects in pregnant women, fetuses, or newborns.Areas covered: This review highlights the efficiency and safety of BoNT injection in pregnancy. and assessed current literature with respect to the use of BoNT for disease treatment during pregnancy.Expert opinion: BoNT injection does not increase the risk of complications in pregnant women and fetuses. However, the use of BoNT to treat disease during pregnancy requires fully informed consent from patients. In addition, further research is needed to determine how to reduce the side effects of BoNT injection during pregnancy (e.g., by improving drug composition, or adjusting the amount of BoNT or the injection interval).

Electrophysiological Findings of Subclinical Lower Motor Neuron Involvement in Degenerative Upper Motor Neuron Diseases

Introduction

The present study is an examination of possible subclinical involvement of lower motor neuron (LMN) in patients with primary lateral sclerosis (PLS) and hereditary spastic paraparesis (HSP) electrophysiologically.

Methods

Nine PLS patients and 5 HSP patients were prospectively analyzed. Jitter measurement with concentric needle electrode (25 mm, 30 G) (CN-jitter) recorded from right extensor digitorum muscle during voluntary contraction with 1 kHz high-pass frequency filter set. European Myelopathy Score (EMS) was used to evaluate disability. The relationship between disability score and jitter values was investigated.

Results

HSP patients had suffered from the disease for longer period of time (p<0.001). Mean jitter values of patients with PLS and HSP were 26.5±12.1 µs and 30.8±34.8 µs, and the number of individual high jitters (>43 microseconds) observed in the PLS and HSP groups was 16/180 and 9/100, respectively without a significant intergroup difference. The ratio of patients with an abnormal jitter study were higher in HSP group (60%) compared to PLS (22%) (p<0.05). Potential pairs with blocking were present in HSP group (7 of 100 potential pairs) but not seen in PLS patients. EMS values were significantly lower in patients having potential pairs with high jitter and blocking compared to those without high jitter and blocking.

Conclusion

The present study has demonstrated that early signs of LMN dysfunction can be detected electrophysiologically by CN-jitter in patients with UMN involvement. These electrophysiological findings in these patients with longer disease duration and lower clinical scores may be explained by spreading of the disease to LMNs or transsynaptic degeneration and its contribution in disease progression.

Botulinum Toxin in the Management of Children with Cerebral Palsy

During the past 25 years, botulinum toxin type A (BoNT-A) has become the most widely used medical intervention in children with cerebral palsy. In this review we consider the gaps in our knowledge in the use of BoNT-A and reasons why muscle morphology and function in children with cerebral palsy are impaired. We review limitations in our knowledge regarding the mechanisms underlying the development of contractures and the difficulty in preventing them. It is clear from this review that injection of BoNT-A in the large muscles of both the upper and lower limbs of children with cerebral palsy will result in a predictable decrease in muscle activity, which is usually reported as a reduction in spasticity, for between 3 and 6 months. These changes are noted by the use of clinical tools such as the Modified Ashworth Scale and the Modified Tardieu Scale. Decreased muscle over-activity usually results in improved range of motion in distal joints. Injection of the gastrocnemius muscle for toe-walking in a child with hemiplegia or diplegia usually has the effect of increasing the passive range of dorsiflexion at the ankle. In our review, we found that this may result in a measurable improvement in gait by the use of observational gait scales or gait analysis, in some children. However, improvements in gait function are not always achieved and are small in magnitude and short lived. We found that some of the differences in outcomes in clinical trials may relate to the use of adjunctive interventions such as serial casting, orthoses, night splints and intensive therapy. We note that the majority of clinical trials of the use of BoNT-A in children with cerebral palsy have focussed on a single injection cycle and this is insufficient to understand the balance between benefit and harm. Most outcomes were reported in terms of changes in muscle tone and there were fewer studies with robust methodology that reported improvements in function. Changes in the domains of activities and participation have rarely been reported in studies to date. There were no clinical reviews to date that consider the findings of studies in human volunteers and in experimental animals and their relevance to clinical protocols. In this review we found that studies in human volunteers and in experimental animals show muscle atrophy after an injection of BoNT-A for at least 12 months. Muscle atrophy was accompanied by loss of contractile elements in muscle and replacement with fat and connective tissue. It is not currently known if these changes, mediated at a molecular level, are reversible. We conclude that there is a need to revise clinical protocols by using BoNT-A more thoughtfully, less frequently and with greatly enhanced monitoring of the effects on injected muscle for both short-term and long-term benefits and harms.

Botulinum Toxin Type A for the Treatment of Lower Limb Spasticity after Stroke

Post-stroke lower limb spasticity impairs balance and gait leading to reduced walking speed, often increasing wheelchair use and caregiver burden. Several studies have shown that appropriate treatments for lower limb spasticity after stroke include injections of botulinum toxin type A (BoNT-A), phenol or alcohol, surgical correction and a rehabilitation program. In the present article, we review the safety and effectiveness of BoNT-A for the treatment of lower limb spasticity after stroke, with a focus on higher doses of BoNT-A. The cumulative body of evidence coming from the randomized clinical trials and open-label studies selected in the article suggest BoNT-A to be safe and efficacious in reducing lower limb spasticity after stroke. Studies of high doses of BoNT-A also showed a greater reduction of severe post-stroke spasticity. In stroke survivors with spasticity of the ankle plantar-flexor muscles, a combined approach between surgery and BoNT-A can be indicated. However, controversy remains about improvement in motor function relative to post-stroke spasticity reduction after BoNT-A treatment.

Three new case reports of Arteriovenous malformation-related Amyotrophic Lateral Sclerosis

Despite recent advances in genetics, in most cases of Amyotrophic Lateral Sclerosis (ALS) no etiological factor can be identified. Cerebral Arteriovenous Malformations (AVMs) have been associated with ALS development in a few studies, but the nature of this connection is unclear. We report here 3 additional cases of young adults, who had undergone repeated embolizations for complex AVMs, and who then developed, after many years, ALS symptoms and signs. In two of these cases Vascular Endothelial Growth Factor (VEGF) levels were found to be extremely high, in contrast to previous reports. Our 3 cases, together with the previously reported ones, suggest that a subgroup of patients with AVMs, with a particular profile of a complex nidus with repeated embolization procedures, are at increased risk of developing ALS. The reason for this association is unclear, but may relate to dysregulation of secreted vascular factors, as suggested by our VEGF results, or more broadly to the neurovascular hypothesis of ALS. Alternatively, a transneuronal type of neurodegeneration may be involved.

Botulinum neurotoxin formulations: overcoming the confusion

Botulinum toxin A is produced by anaerobic spore-forming bacteria and is used for various therapeutic and cosmetic purposes. Botulinum toxin A injections are the most popular nonsurgical procedure worldwide. Despite an increased demand for botulinum toxin A injections, the clinical pharmacology and differences in formulation of commonly available products are poorly understood. The various products available in the market are unique and vary in terms of units, chemical properties, biological activities, and weight, and are therefore not interchangeable. For safe clinical practice and to achieve optimal results, the practitioners need to understand the clinical issues of potency, conversion ratio, and safety issues (toxin spread and immunogenicity). In this paper, the basic clinical pharmacology of botulinum toxin A and differences between onabotulinum toxin A, abobotulinum toxin A, and incobotulinum toxin A are discussed.

Four-dimensional ultrasound guidance for pelvic floor Botulinum toxin-A injection in chronic pelvic pain: a novel technique

OBJECTIVE

Botulinum toxin-A (BoNT-A) is used in the treatment of pelvic floor muscle overactivity associated with chronic pelvic pain (CPP) when conservative methods such as physiotherapy are not effective or appropriate. Traditional injection techniques require finger-guided palpation of pelvic floor muscles with concurrent insertion of the needle. The aim of this study was to describe a novel technique for the injection of BoNT-A into the pelvic floor musculature using four-dimensional ultrasound (4D-US) guidance.

METHODS

Thirty-one BoNT-A injections were performed using the new technique between October 2013 and January 2016, on women scheduled to have BoNT-A injection for pelvic floor muscle overactivity and CPP. The pelvic floor was assessed by 4D-US. A test injection of saline was performed to confirm location of the needle, then BoNT-A was injected into the muscle under ultrasound guidance, using 4D-US to confirm that the fluid expanded and tracked along muscle fibers.

RESULTS

The saline test confirmed correct location of the needle following a median of 1 (range, 1-3) attempt at needle placement. In all 31 instances, satisfactory injection of BoNT-A, with 4D-US confirmation of fluid expansion within the muscle body, was performed.

CONCLUSIONS

Injection of BoNT-A under 4D-US guidance is feasible and allows accurate placement into the target muscle in women with pelvic floor muscle overactivity associated with CPP. This technique may provide a safer alternative to finger-guided methods, owing to a lower likelihood of operator needle-stick injury. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Neurophysiological Measures of Efficacy and Safety for Botulinum Toxin Injection in Facial and Bulbar Muscles: Special Considerations

Botulinum toxin (BoNT) injections into facial and bulbar muscles are widely and increasingly used as medical treatments for cervical and facial dystonia, facial hemispasm, correction of facial palsy, hyperhidrosis, as well as cosmetic treatment of glabellar lines associated with grief and anger. Although BoNT treatment is generally considered safe, the diffusion of the toxin to surrounding muscles may result in complications, including difficulties swallowing, in a dose-dependent manner. The sensitivity of clinical examination for detecting adverse events after BoNT treatment is limited. Few reports have highlighted the potential effects on other muscles in the facial area due to the spreading of the toxin. The possibilities of spreading and thus unknown pharmacological BoNT effects in non-targeted muscles emphasise the importance of correct administration of BoNT in terms of dose selection, injection points, and appropriate effect surveillance. In this review article, we will focus on novel objective measures of efficacy and safety regarding BoNT treatment of facial muscles and the reasons why this is important.

Detection of Botulinum Toxin Muscle Effect in Humans Using Magnetic Resonance Imaging: A Qualitative Case Series

BACKGROUND

Although important for dosing and dilution, there are few data describing botulinum toxin (BT) movement in human muscle.

OBJECTIVE

To better understand BT movement within human muscle.

DESIGN

Proof-of-concept study with descriptive case series.

SETTING

Outpatient academic practice.

PARTICIPANTS

Five subjects with stroke who were BT naive with a mean age of 60.4 ± 14 years and time poststroke of 4.6 ± 3.7 years.

METHODS

Three standardized injections were given to the lateral gastrocnemius muscle (LGM): 2 contained 25 units (U) of onabotulinumtoxinA (Botox) in 0.25 mL of saline solution and the third 0.25 mL of saline solution only. The tibialis anterior muscle (TAM) was not injected in any subject. A leg magnetic resonance image was obtained at baseline, 2 months, and 3 months later with a 3.0 Tesla Siemens scanner. Three muscles, the LGM, lateral soleus muscle (LSM), and TAM, were manually outlined on the T2 mapping sequence at each time point. A histogram of T2 relaxation times (T2-RT) for all voxels at baseline was used to calculate a mean and standard deviation (SD) T2-RT for each muscle. Botulinum toxin muscle effect (BTME) at 2 months and 3 months was defined as a subject- and muscle-specific T2-RT voxel threshold ≥3 SD above the baseline mean at or near BT injection sites.

MAIN OUTCOME MEASURES

BTME volume for each leg magnetic resonance imaging slice at 3 time points and 3 muscles for all subjects.

RESULTS

One subject missed the 3-month scan, leaving 18 potential observations of BTME. Little to no BTME effect was seen in the noninjected TAM. A BTME was detected in the LGM in 13 of 18 possible observations, and no effect was detected in 5 observations. Possible BTME effect was seen in the LSM in 3 subjects due to either diffusion through fascia or needle misplacement. Volume of BTME, as defined here, appeared to be substantially greater than the 0.25-mL injection volume.

CONCLUSIONS

This descriptive case series is among the first attempts to quantify BTME within human muscle. Our findings are preliminary and are limited by a few inconsistencies. However, we conclude that use of magnetic resonance imaging to detect the volume of BTME is feasible and may assist researchers in modeling the spread and diffusion of BT within human muscle.

LEVEL OF EVIDENCE

IV.

Effects of onabotulinumtoxinA on cardiac function following intradetrusor injections

OnabotulinumtoxinA intradetrusor injections are considered a highly effective localized therapy for refractory detrusor overactivity. However, despite evidence for distant systemic effects of onabotulinumtoxinA, little is known on potential systemic side effects following intradetrusor injections. Given that onabotulinumtoxinA is a highly potent toxin this is an important safety issue specifically with regard to repeat injections and parallel treatments with botulinum toxin. Hence, it was the purpose of this prospective study to investigate, using heart rate variability (HRV) analysis, whether onabotulinumtoxinA causes systemic effects on cardiac function following intradetrusor injections. Patients with neurogenic detrusor overactivity (NDO) and age-matched healthy controls were recruited. Concomitant medication and diseases affecting the cardio-vascular system were exclusion criteria. A 3-channel resting electrocardiogram (ECG) was recorded in supine position for 15min during four consecutive visits: 1) 2weeks prior onabotulinumtoxinA intradetrusor injections, 2) 10min prior injections, 3) 30min after injections, and 4) 6weeks after injections. NDO patients received intradetrusor injections (300units Botox®) between visits 2 and 3. The control group had no intervention. Short-term (5min) HRV analysis included assessment of frequency and time domain parameters. Statistical analysis was performed using ANOVA with repeated measures and the t-test. Due to multiple comparisons, α was corrected to 0.0125 (Bonferroni method). Twelve healthy volunteers (5♀, 7♂; 46±12years old) and 12 NDO patients (5♀, 7♂; 46±13years old) completed all measurements. Comparing both groups, resting heart rate was significantly higher in the patients group at visit 4 only. No further significant differences in time and frequency domain parameters were discovered. Within the NDO group, standard deviation of the normal to normal intervals (SDNN) in the ECG demonstrated a significant decrease (1.70 to 1.53ms, p=0.003) from visit 3 to 4, whereas the total power (TP) significantly increased (3.05 to 3.29ms², p=0.009) from visit 2 to 3. This increase subsided until visit 4.

STUDY LIMITATIONS

single treatment investigation under resting conditions only. In conclusion, onabotulinumtoxinA intradetrusor injections do not seem to affect resting state cardiac function. Short-term changes such as total power might rather result from natural cardio-vascular responses to the procedure itself (e.g. discomfort, stress). Further detailed investigations also under physical stress and repeated injections are necessary to fully exclude systemic cardiac side effects of onabotulinumtoxinA intradetrusor injections.

Conversion Ratio between Botox®, Dysport®, and Xeomin® in Clinical Practice

Botulinum neurotoxin has revolutionized the treatment of spasticity and is now administered worldwide. There are currently three leading botulinum neurotoxin type A products available in the Western Hemisphere: onabotulinum toxin-A (ONA) Botox(®), abobotulinum toxin-A (ABO), Dysport(®), and incobotulinum toxin A (INCO, Xeomin(®)). Although the efficacies are similar, there is an intense debate regarding the comparability of various preparations. Here we will address the clinical issues of potency and conversion ratios, as well as safety issues such as toxin spread and immunogenicity, to provide guidance for BoNT-A use in clinical practice. INCO was shown to be as effective as ONA with a comparable adverse event profile when a clinical conversion ratio of 1:1 was used. The available clinical and preclinical data suggest that a conversion ratio ABO:ONA of 3:1-or even lower-could be appropriate for treating spasticity, cervical dystonia, and blepharospasm or hemifacial spasm. A higher conversion ratio may lead to an overdosing of ABO. While uncommon, distant spread may occur; however, several factors other than the pharmaceutical preparation are thought to affect spread. Finally, whereas the three products have similar efficacy when properly dosed, ABO has a better cost-efficacy profile.

Adverse Clinical Effects of Botulinum Toxin Intramuscular Injections for Spasticity

OBJECTIVE

The adverse events (AEs) with botulinum toxin type-A (BoNTA), used for indications other than spasticity, are widely reported in the literature. However, the site, dose, and frequency of injections are different for spasticity when compared to the treatment for other conditions and hence the AEs may be different as well. The objective of this study was to summarize the AEs reported in Canada and systematically review the AEs with intramuscular botulinum toxin injections to treat focal spasticity.

METHODS

Data were gathered from Health Canada (2009-2013) and major electronic databases.

RESULTS

In a 4 year period, 285 AEs were reported. OnabotulinumtoxinA (n=272 events): 68% females, 53% serious, 18% hospitalization, and 8% fatalities. The type of AEs reported were - muscle weakness (19%), oropharyngeal (14%), respiratory (14%), eye related (8%), bowel/bladder related (8%), and infection (5%). IncobotulinumtoxinA (n=13): 38% females, 62% serious, and 54% hospitalization. The type of AEs reported were - muscle weakness (15%), oropharyngeal (15%), respiratory (38%), eye related (23%), bowel/bladder related (15%), and infection (15%). Commonly reported AEs in the literature were muscle weakness, pain, oropharyngeal, bowel/bladder, blood circulation, neurological, gait, and respiratory problems.

CONCLUSION

While BoNTA is useful in managing spasticity, future studies need to investigate the factors that can minimize AEs. A better understanding of the underlying mechanisms of the AEs can also improve guidelines for BoNTA administration and enhance outcomes.

Single-fiber electromyography analysis of botulinum toxin diffusion in patients with fatigue and pseudobotulism

OBJECTIVE

To characterize electromyographic abnormalities according to symptoms (asymptomatic, fatigue, pseudobotulism) reported 1 month after botulinum toxin injection.

DESIGN

Retrospective, single-center study comparing single-fiber electromyography (SFEMG) in the extensor digitorum communis (EDC) or orbicularis oculi (OO) muscles.

SETTING

Hospital.

PARTICIPANTS

Four groups of adults treated for spasticity or neurologic bladder hyperactivity (N=55): control group (asymptomatic patients: n=17), fatigue group (unusual fatigue with no weakness: n=15), pseudobotulism group (muscle weakness and/or visual disturbance: n=20), and botulism group (from intensive care unit of the same hospital: n=3).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Mean jitter, percentage of pathologic fibers, and percentage of blocked fibers were compared between groups.

RESULTS

SFEMG was abnormal for 17.6% of control patients and 75% of patients in the pseudobotulism group. There were no differences between the control and fatigue groups. Mean jitter, percentage of pathologic fibers, and percentage of blocked fibers of the EDC muscle were significantly higher in the pseudobotulism group than in the fatigue and control groups. There were no differences between groups for the OO muscle. The SFEMG results in the botulism group were qualitatively similar to those of the pseudobotulism group.

CONCLUSIONS

SFEMG of the EDC muscle confirmed diffusion of the toxin into muscles distant from the injection site in the pseudobotulism group. SFEMG in the OO muscle is not useful for the diagnosis of diffusion. No major signs of diffusion of botulinum toxin type A were found away from the injection site in patients with fatigue but no motor weakness. Such fatigue may be related to other mechanisms.

Serious and long-term adverse events associated with the therapeutic and cosmetic use of botulinum toxin

Although botulinum toxin is generally considered safe, its widespread use and the constantly expanded indications raise safety issues. This study aimed to review the serious and long-term adverse events associated with the therapeutic and cosmetic use of botulinum toxin. Serious adverse events included dysphagia, respiratory compromise, generalized muscle weakness, marked bilateral ptosis, pseudoaneurysm of the frontal branch of the temporal artery, necrotizing fasciitis, sarcoidal granuloma, Fournier gangrene, and cervical kyphosis. Death was attributed to botulism or anaphylactic shock. In conclusion, botulinum toxin may cause serious adverse events, which are more common after its therapeutic use, but can also be noticed after its cosmetic use. Thorough knowledge of the anatomy of the treated muscles and of the pharmacology of the drug is imperative to avoid serious adverse events.

Paclitaxel is an inhibitor and its boron dipyrromethene derivative is a fluorescent recognition agent for botulinum neurotoxin subtype A

We have successfully identified one new inhibitor and one new fluorescent recognition agent for the botulinum neurotoxin subtype A (BoNT/A) using the virtual screening protocol "protein scanning with virtual ligand screening" (PSVLS). Hit selection used an in-house developed holistic binding scoring method. Selected hits were tested experimentally for inhibitory activity using fluorescence resonance energy transfer (FRET) assays against the light chain (catalytic domain) of BoNT/A. Ligand binding was determined against the light and heavy chain BoNT/A complex through either radiolabeled ligand binding assays (nonfluorescent ligands) or fluorescence intensity assays (fluorescent ligands). These experimental assays have confirmed one compound (paclitaxel) to inhibit BoNT/A's proteolytic activity experimentally with an IC50 of 5.2 μM. A fluorescent derivative was also confirmed to bind to the toxin and therefore is a suitable candidate for the rational design of new detection agents and for the development of fluorescence-based multiprobe detection assays.

Abo-, inco-, ona-, and rima-botulinum toxins in clinical therapy: a primer

Botulinum neurotoxin (BoNT) is an acetylcholine release inhibitor and a neuromuscular-blocking agent used for the treatment of a variety of medical and cosmetic indications. Currently, in the United States, there are four BoNT formulations licensed for use: abobotulinumtoxinA, incobotulinumtoxinA, onabotulinumtoxinA, and rimabotulinumtoxinB. These revised name designations were established to reinforce the understanding that each BoNT product has an individual potency and is not interchangeable with any other BoNT product. The therapeutic use of BoNTs is expanding and new formulations are on the horizon. This article is a primer that describes distinctions among currently available, licensed BoNT formulations. Toxin pharmacology, product characteristics, storage, handling, preparation, and dosages will be reviewed. In addition, issues related to dose equivalency ratios, immunogenicity, potency, and toxin spread will be discussed. Therapeutic indications and safety are discussed briefly. Knowledge of the available and licensed BoNT formulations and the ability to make distinctions in toxin pharmacology, product characteristics, and indications are vital for product selection, preparation, drug information, avoidance of drug errors, quality assurance, and patient safety.

Neurogenic bladder

Congenital anomalies such as meningomyelocele and diseases/damage of the central, peripheral, or autonomic nervous systems may produce neurogenic bladder dysfunction, which untreated can result in progressive renal damage, adverse physical effects including decubiti and urinary tract infections, and psychological and social sequelae related to urinary incontinence. A comprehensive bladder-retraining program that incorporates appropriate education, training, medication, and surgical interventions can mitigate the adverse consequences of neurogenic bladder dysfunction and improve both quantity and quality of life. The goals of bladder retraining for neurogenic bladder dysfunction are prevention of urinary incontinence, urinary tract infections, detrusor overdistension, and progressive upper urinary tract damage due to chronic, excessive detrusor pressures. Understanding the physiology and pathophysiology of micturition is essential to select appropriate pharmacologic and surgical interventions to achieve these goals. Future perspectives on potential pharmacological, surgical, and regenerative medicine options for treating neurogenic bladder dysfunction are also presented.

Field effect of two commercial preparations of botulinum toxin type A: a prospective, double-blind, randomized clinical trial

BACKGROUND

The dose equivalence of commonly used commercial preparations of botulinum toxin type A, Dysport (abotulinumtoxinA [ABO] 500 U, Ipsen Biopharm Limited, Wrexham, United Kingdom) and Botox (onabotulinumtoxinA [ONA] 100 U, Allergan, Irvine, CA), remains unclear.

OBJECTIVE

We sought to evaluate the field effect for ABO and ONA at dose equivalences of 2.5:1.0 U and 2.0:1.0 U, in both muscular and sweat gland activity.

METHODS

In all, 59 female patients with forehead wrinkles were enrolled. Patients were randomized for dose equivalence between ABO and ONA, group A (2.0:1.0 U, ABO:ONA) or group B (2.5:1.0 U, ABO:ONA) administered in the frontalis muscles. Clinical assessment, Minor test, and electromyography evaluations were performed at baseline, 28 days, and 112 days.

RESULTS

In group B, the field of anhidrotic effect of ABO showed a greater area and larger horizontal diameter than ONA at 28 and 112 days. At maximum frontalis muscle activity (day 112) patients receiving ABO demonstrated greater improvement based on the Wrinkle Severity Scale. No differences were found in frontalis muscle activity at rest between groups A and B based on results of Wrinkle Severity Scale, electromyography, and interindividual variability data at 28 and 112 days.

LIMITATIONS

Currently, there are no objective measurements other than electromyography to evaluate the field effect of botulinum toxin type A in muscles.

CONCLUSION

At a dose equivalence of 2.0:1.0 U (ABO:ONA), similar field effects were found for both muscle and sweat gland activity. At a higher dose equivalence of 2.5:1.0 U (ABO:ONA), injections of ABO showed greater area and larger horizontal diameter in field of anhidrotic effect at 28 and 112 days than ONA.

Pilot study evaluating the safety of intradetrusor injections of botulinum toxin type A: investigation of generalized spread using single-fiber EMG

AIMS

Intradetrusor botulinum toxin type-A injections are a novel therapy for treatment of neurogenic overactive bladder resistant to parasympatholytic treatment. In rare cases, however, it may be associated with generalized muscle weakness. Single-fiber electromyographic (SFEMG) analysis of neuromuscular jitter (NJ) was used to study OnabotulinumtoxinA (BOTOX®) migration to striated muscle.

METHODS

This study comprised a prospective, single-center investigation of 21 spinal cord injured patients receiving intradetrusor OnabotulinumtoxinA. Clinical tolerance was assessed through muscle testing and para-clinical tolerance by systematic analysis of NJ in muscles distant from the bladder.

RESULTS

Twenty-one patients (13 males, 8 females) received one intradetrusor injection of 300  U OnabotulinumtoxinA. Mean age was 42.1  ±  14.4 and mean number of injections prior to study inclusion was 2.6  ± 1.7. Clinical and para-clinical assessments were performed on average 26 days  ±  8 days post-OnabotulinumtoxinA injection. Seven patients had abnormal NJ results on SFEMG, but no patient had evidence of blocking. Four patients complained of tiredness (one with NJ abnormalities).

CONCLUSIONS

Patients showed good tolerance to intradetrusor OnabotulinumtoxinA injections. Tiredness was not associated with generalized muscle weakness since testing remained unchanged and NMJ was normal in three of four patients. NJ analysis was abnormal in 7 of 21 patients, but this was not considered serious and there was no evidence of muscle fiber block. These results support the safety of bladder injections of OnabotulinumtoxinA and suggest that, although migration of OnabotulinumtoxinA to other muscle groups may impair NJ function in a minority of patients, this does not correlate with symptoms of tiredness or muscle weakness.

Botulinum neurotoxin-A does not spread to distant muscles after intragastric injection: A double-blind single-fiber electromyography study

The purpose of this study was to perform a careful neurophysiological examination to identify subclinical signs of botulinum toxin spread distant to the injection site following intragastric injection for obesity treatment. Single-fiber electromyography of extensor digitorum communis and repetitive stimulation of abductor digiti minimi were performed before and 8 days after multiple intragastric injections of botulinum toxin A (Botox, 200 U per patient) or placebo. The study was performed in a randomized double-blind fashion. No patient in either group displayed results indicative of neuromuscular dysfunction either before or after the treatment. No significant change in muscle jitter was observed when comparing baseline with the after-treatment evaluation in either group, and no significant differences between groups were observed. After intragastric botulinum toxin injection no subclinical sign of distant spread was observed.

Clinical consequences of reinnervation disorders after focal peripheral nerve lesions

Axonal regeneration and organ reinnervation are the necessary steps for functional recovery after a nerve lesion. However, these processes are frequently accompanied by collateral events that may not be beneficial, such as: (1) Uncontrolled branching of growing axons at the lesion site. (2) Misdirection of axons and target organ reinnervation errors, (3) Enhancement of excitability of the parent neuron, and (4) Compensatory activity in non-damaged nerves. Each one of those possible problems or a combination of them can be the underlying pathophysiological mechanism for some clinical conditions seen as a consequence of a nerve lesion. Reinnervation-related motor disorders are more likely to occur with lesions affecting nerves which innervate muscles with antagonistic functions, such as the facial, the laryngeal and the ulnar nerves. Motor disorders are better demonstrated than sensory disturbances, which might follow similar patterns. In some instances, the available examination methods give only scarce evidence for the positive diagnosis of reinnervation-related disorders in humans and the diagnosis of such condition can only be based on clinical observation. Whatever the lesion, though, the restitution of complex functions such as fine motor control and sensory discrimination would require not only a successful regeneration process but also a central nervous system reorganization in order to integrate the newly formed peripheral nerve structure into the prepared motor programs and sensory patterns.