The Pharmacology of Botulinum Toxin Type A

The aim of this chapter is to structure current information clarifying the most disputable issues of botulinum neurotoxin type A (BoNT/A) pharmacology after systemic (botulism) impact and local medical application. Botulinum neurotoxin (BoNT) pharmacological features evaluated open ways to study factors affecting its biological activity: to extend/shorten its effect duration, to increase/decrease BoNT sensitivity in specific patient populations. The chapter presents unique molecular mechanisms underlying BoNT/A pharmacokinetics and pharmacodynamics: entering the body, distribution, receptor binding, translocation, mediator release suppression, zinc metabolism as well as factors affecting body sensitivity to BoNT at each of those stages. The specific biological effects of BoNT/A, which may underlie its analgesic, anticancer and anti-inflammatory effects, are described. Botulinum neurotoxin pharmacokinetics and pharmacodynamics features discussed herein represent significant clinical relevance since they determine botulinum treatment safety and effectiveness. And also they open ways to develop both BoNT-based therapies and anti-botulinic agents.

Acral Necrosis in a COVID-19-Infected Man Treated with Botulinum Toxin Type A

COVID-19 has been associated with acral ischemia and digital necrosis. Standard treatment of acral ischemia and digital or acral necrosis includes ongoing therapy with vasodilators and anticoagulants. However, these treatments are not always efficient to avoid the progression of necroses, which in the worst case can lead to amputation. Here, we report a case in which interdigital Botox^® (botulinum toxin type A) nerve cord injection stopped the progression of acral necroses arising from an underlying vasculopathy due to COVID-19. Moreover, Botox^® injection eliminated inflammation in the affected acral area within 2 weeks. This is the first case report to suggest Botox^® injection as a new and improving treatment for acral necroses due to COVID-19.

Dose selection of Incobotulinumtoxin A for the treatment of spasticity and sialorrhea in cerebral palsy: results of a retrospective multicenter study

Introduction. In patients with infantile cerebral palsy (CP), botulinum therapy is used to treat both muscle tone disorders and sialorrhea. Therefore, it is logical to use one preparation of botulinum toxin type A to treat spasticity and sialorrhea in one injection procedure. The aim of the work is to conduct a retrospective analysis of data from 15 centres that treat patients with cerebral palsy and use the botulinum therapy method to determine the optimal doses of IncobotulinumtoxinA (IBTA) for the treatment of spasticity and chronic sialorrhea in real clinical practice. Materials and methods. The treatment results of 389 children with cerebral palsy (including 211 (54.2%) boys) with IBTA were analyzed. The majority were children with bilateral forms of cerebral palsy - 312 (80.2%). The average age of the patients was 5.27 ± 3.71 years, the average weight of the patients was 18.8 ± 10.9 kg. Results. The total dose of IBTA in the group of 389 patients with cerebral palsy for the treatment of spasticity was 163.74 ± 80.65 U (25-550; 95% CI 155.7-171.7) and 10.4 ± 5.4 U/kg body weight (1,25-29.7; 95% CI 9.8-10.9). The total dose of IBTA in the group of patients with cerebral palsy with simultaneous treatment of spasticity and chronic sialorrhea (n = 16) was significantly higher: 267.18 ± 124.57 U (115-570; 95% CI 200.8-333.6) and 13, 0 ± 7.1 U/kg (5.8-24.6; 95% CI 9.2-16.8). In the lower extremities, the most frequent target muscles were the gastrocnemius (55.0% of cases; 95% CI 49.9-60.0) and semitendinosus / semimembranous muscle (46.3% of cases; 95% CI 41.2-51.4 ), and in the upper limbs - pronator teres (48.6% of cases; 95% CI 43.5-53.7) and biceps brachii (28.8% of cases; 95% CI 24.3-33.6). Limitations of the study. The limitations of our work are the use of an open retrospective study format, a relatively small sample of patients with chronic sialorrhea, the absence of long-term follow-up of patients and the results of repeated IBTA injections. Conclusion. If it is necessary to use botulinum therapy for the treatment of spasticity and sialorrhea in a child with CP, it is optimal to use the product IncobotulinumtoxinA, which will allow correction of two pathological manifestations in one procedure and can shorten the intervals between repeated injection cycles.

Wound Botulism Among Persons Who Inject Black Tar Heroin in New Mexico, 2016

Outbreaks of wound botulism are rare, but clinicians and health departments should maintain suspicion for signs, symptoms, and risk factors of wound botulism among persons who inject drugs in order to initiate treatment quickly. This report describes an outbreak of three wound botulism cases among persons in two adjacent counties who injected drugs. Provisional information about these cases was previously published in the CDC National Botulism Surveillance Summary. All three cases in this outbreak were laboratory-confirmed, including one case with detection of botulinum toxin type A in a wound culture sample taken 43 days after last possible heroin exposure. Findings highlight the delay in diagnosis which led to prolonged hospitalization and the persistence of botulinum toxin in one patient.

Triceps Surae Muscle Characteristics in Spastic Hemiparetic Stroke Survivors Treated with Botulinum Toxin Type A: Clinical Implications from Ultrasonographic Evaluation

Equinovarus foot is one of the most commonly spasticity related conditions in stroke survivors, leading to an impaired gait and poor functional performances. Notably, spastic muscles undergo a dynamic evolution following typical pathophysiological patterns. Botulinum Neurotoxin Type A (BoNT-A) is the gold standard for focal spasticity treatment, and ultrasound (US) imaging is widely recommended to guide injections and monitor muscle evolution. The role of BoNT-A in influencing muscle fibroadipose degeneration is still unclear. In this study, we analyzed medial gastrocnemius (MG) and soleus (SOL) US characteristics (cross-sectional area, muscle thickness, pennation angle, and mean echo intensity) in 53 patients. MG and SOL alterations, compared to the unaffected side, depend on the spasticity only and not on the BoNT-A treatment. In functionally preserved patients (functional ambulation classification, FAC > 3; modified Ashworth scale, MAS ≤ 2), the ultrasonographic changes of MG compared to ipsilateral SOL observed in the paretic limb alone seems to be due to histological, anatomical, pathophysiological, and biomechanical differences between the two muscles. In subjects with poor walking capability and more severe spasticity, such ipsilateral difference was found in both calves. In conclusion, BoNT-A does not seem to influence muscle degeneration. Similar muscles undergo different evolution depending on the grade of walking deficit and spasticity.

Botulinum Toxin Type A for Lumbar Sympathetic Ganglion Block in Complex Regional Pain Syndrome: A Randomized Trial

Background The present study was designed to test the hypothesis that botulinum toxin would prolong the duration of a lumbar sympathetic block measured through a sustained increase in skin temperature. The authors performed a randomized, double-blind, controlled trial to investigate the clinical outcome of botulinum toxin type A for lumbar sympathetic ganglion block in patients with complex regional pain syndrome. Methods Lumbar sympathetic ganglion block was conducted in patients with lower-extremity complex regional pain syndrome using 75 IU of botulinum toxin type A (botulinum toxin group) and local anesthetic (control group). The primary outcome was the change in the relative temperature difference on the blocked sole compared with the contralateral sole at 1 postoperative month. The secondary outcomes were the 3-month changes in relative temperature differences, as well as the pain intensity changes. Results A total of 48 participants (N = 24/group) were randomly assigned. The change in relative temperature increase was higher in the botulinum toxin group than in the control group (1.0°C ± 1.3 vs. 0.1°C ± 0.8, respectively; difference: 0.9°C [95% CI, 0.3 to 1.5]; P = 0.006), which was maintained at 3 months (1.1°C ± 0.8 vs. –0.2°C ± 1.2, respectively; P = 0.009). Moreover, pain intensity was greatly reduced in the botulinum toxin group compared with the control group at 1 month (–2.2 ± 1.0 vs. –1.0 ± 1.6, respectively; P = 0.003) and 3 months (–2.0 ± 1.0 vs. –0.6 ± 1.6, respectively; P = 0.003). There were no severe adverse events pertinent to botulinum toxin injection. Conclusions In patients with complex regional pain syndrome, lumbar sympathetic ganglion block using botulinum toxin type A increased the temperature of the affected foot for 3 months and also reduced the pain. Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New