Botulinum Toxin in Painful Tardive Dyskinesia

A review on approach to a twitchy tongue in neurology

BACKGROUND

Several etiologies are responsible for presentation of a twitching tongue in clinical practice. Some of these etiologies cause an isolated hyperkinetic tongue muscle, and some others cause it along with other signs and symptoms.

OBJECTIVES

The present paper aims to review the causes, pathology, and presentations reported with twitchy tongue. An anatomical basis of the etiologies responsible for presentation of a twitchy tongue and hyperkinetic movement disorders of this muscle is pursued.

METHOD

The reporting of this systematic review was guided by the standards of the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) Statement. All of the research papers conducted with keywords described in the method section between 2000 and 2022 were used, and review articles and articles without any human subject and without any described hyperkinetic movement disorders of the tongue were excluded.

RESULTS

All of the etiologies responsible for hyperkinetic movement disorders of tongue were listed in the basis of their anatomical site of effect; cortical region, basal ganglia, cerebellum, brain stem, nucleus and nerve, and neuromuscular junction. One last remained part is the "not classified" section, which contains the etiologies with no particular anatomical origin.

CONCLUSION

There are a variety of responsible etiologies for presentation of a twitchy tongue, and in the matter of a complaint of hyperkinetic tongue presentation, physicians should consider anatomical, functional, and psychological etiologies and other signs and symptoms must be participated in the diagnosis process to achieve a proper medical decision.

Pathophysiology, prognosis and treatment of tardive dyskinesia

Tardive dyskinesia (TD), a movement disorder associated with antipsychotics, most frequently affects the lower face and jaw muscles, but can also affect walking, breathing and use of the hands and limbs. Knowledge of TD among physicians may be limited, and the pathophysiology of TD is poorly understood. We conducted this review to summarise the current knowledge surrounding the pathophysiology of TD and present recommendations for prevention and treatment based on a literature search and roundtable discussion attended by psychiatrists in Japan. It has been suggested that dopamine hypersensitivity, damaged gamma-aminobutyric acidergic neurons and/or increased production of reactive oxygen species may contribute to development of TD. Symptoms can profoundly affect everyday life; patients who develop TD have poorer prognoses, worse health-related quality of life, greater social withdrawal and higher mortality than patients without TD. Traditional treatment options include dietary supplements, although evidence for their effectiveness is low. Among pharmaceutical interventions, there is moderate evidence that switching to the second-generation antipsychotic clozapine, which has a lower affinity for dopamine D2 receptors than other antipsychotics, may improve symptoms. Vesicular monoamine transporter 2 (VMAT-2) inhibitors, which oppose the increased dopaminergic activity associated with prolonged antipsychotic use by interfering with dopamine uptake and storage, have the strongest evidence for efficacy. VMAT-2 inhibitors are approved in the United States for the treatment of TD, and the first VMAT-2 inhibitor was approved in Japan for this indication in March 2022. Most guidelines recommend treating TD by first reducing the dose of antipsychotics or switching to clozapine or other second-generation antipsychotics, which have a lower association with TD than first-generation antipsychotics. We recommend focusing on prevention and monitoring for TD when prescribing antipsychotics, given that TD is often irreversible. Physicians should treat with antipsychotics only when necessary and at the lowest effective dose, and frequently monitor for TD symptoms.

Plain Language Summary

Plain Language Summary (In Japanese).

Visual Summary

Visual Summary (In Japanese).

Non-VMAT2 inhibitor treatments for the treatment of tardive dyskinesia

Although VMAT2-inhibitors are now established as first-line treatment for tardive dyskinesia, not all patients respond to, or tolerate them. Numerous other agents have been adopted to treat tardive dyskinesia, but with variable results and generally lower quality methodologic reports. Amantadine is the most promising but benzodiazepines, branched chain neutral amino acids, Vitamin B6, several nutraceuticals, and botulinum toxin injections might help some patients. In all cases, better placebo controlled trials are needed before definitive recommendations can be made.

Tardive Dyskinesia Associated with Atypical Antipsychotics: Prevalence, Mechanisms and Management Strategies

All antipsychotics, including the atypical antipsychotics (AAPs), may cause tardive dyskinesia (TD), a potentially irreversible movement disorder, the pathophysiology of which is currently unknown. The prevention and treatment of TD remain major challenges for clinicians. We conducted a PubMed search to review the prevalence and etiology of and management strategies for TD associated with AAPs. TD prevalence rates varied substantially between studies, with an estimated prevalence of around 20% in patients using AAPs. The risk of TD is lower with AAPs than with typical antipsychotics (TAPs) but remains a problem because AAPs are increasingly being prescribed. Important risk factors associated with TD include the duration of antipsychotic use, age, and ethnicity other than Caucasian. Theories about the etiology of TD include supersensitivity of the dopamine receptors and oxidative stress, but other neurotransmitters and factors are probably involved. Studies concerning the management of TD have considerable methodological limitations. Thus, recommendations for the management of TD are based on a few trials and clinical experience, and no general guidelines for the management of TD can be established. The best management strategy remains prevention. Caution is required when prescribing antipsychotics, and regular screening is needed for early detection of TD. Other strategies may include reducing the AAP dosage, switching to clozapine, or administering vesicular monoamine transporter (VMAT)-2 inhibitors. In severe cases, local injections of botulinum toxin or deep brain stimulation may be considered. More clinical trials in larger samples are needed to gather valid information on the effect of interventions targeting TD.

An update on new and unique uses of botulinum toxin in movement disorders

The therapeutic applications of botulinum toxin (BoNT) have grown manifold since its initial approval in 1989 by the US Food and Drug Administration (FDA) for the treatment of strabismus, blepharospasm, and other facial spasms. Although it is the most potent biologic toxin known to man, long-term studies have established its safety in the treatment of a variety of neurologic and non-neurologic disorders. This review focuses on some novel and uncommon uses of BoNT in the treatment of movement disorders, such as oromandibular dystonia, including bruxism, anterocollis, camptocormia, tremor, tics, tardive and levodopa-induced dyskinesia, and restless legs syndrome. Despite a paucity of randomized controlled trials and lack of FDA approval for these movement disorders, there is growing body of evidence that BoNT provides benefit to patients with these hyperkinetic movement disorders and that BoNT is a safe treatment when used by clinicians skilled in the administration of the drug for these conditions.

Antipsychotic-induced Tardive dyskinesia: from biological basis to clinical management

INTRODUCTION

Tardive dyskinesia (TD) is a chronic and disabling movement disorder with a complex pathophysiological basis. A significant percentage of patients does not receive correct diagnosis, resulting in delayed or inaccurate treatment and poor outcome. Therefore, there is a critical need for prompt recognition, implementation of efficacious treatment regimens and long-term follow up of patients with TD. Areas covered: The current paper provides an overview of emerging data concerning proposed pathophysiology theories, epidemiology, risk factors, and therapeutic strategies for TD. Expert commentary: Despite considerable research efforts, TD remains a challenge in the treatment of psychosis as the available strategies remain sub-optimal. The best scenario will always be the prophylaxis or prevention of TD, which entails limiting the use of antipsychotics.

Drug-Induced Dyskinesia, Part 2: Treatment of Tardive Dyskinesia

Dyskinesias encompass a variety of different hyperkinetic phenomenologies, particularly chorea, dystonia, stereotypies, and akathisia. The main types of drug-induced dyskinesias include levodopa-induced dyskinesia (LID) in patients with Parkinson's disease and tardive syndrome (TS), typically present in patients with psychiatric or gastrointenstinal disorders treated with dopamine receptor blocking drugs, also referred to as neuroleptics. Besides preventive measures (i.e., avoiding the use of the offending drugs), general treatment strategies include slow taper of the offending agent and use of dopamine-depleting agents like tetrabenazine. Botulinum toxin may be helpful for wearing off focal dystonia and some forms of tardive dystonia. Deep brain stimulation is usually reserved for patients with disabling motor fluctuations, LID, and for severe TS that cannot be managed medically.

Tardive dyskinesia: therapeutic options for an increasingly common disorder

Tardive dyskinesia (TD) is a serious, often disabling, movement disorder that is caused by medications that block dopamine receptors (i.e., neuroleptics, anti-emetics). There is currently no standard treatment approach for physicians confronted with such patients. This may be the result of notions that TD is disappearing because of the switch to second-generation antipsychotic agents and that it is largely reversible. In this article we demonstrate that second-generation antipsychotics do, indeed, cause TD and, in fact, the frequency is likely higher than expected because of growing off-label uses and a tripling of prescriptions written in the last 10 years. In addition, studies demonstrate that TD actually remits in only a minority of patients when these drugs are withdrawn. Furthermore, neuroleptic agents are often utilized to treat TD, despite prolonged exposure being a risk factor for irreversibility. The outcome of these trends is a growing population afflicted with TD. We review non-neuroleptic agents that have shown positive results in small, early-phase, blinded trials, including tetrabenazine, amantadine, levetiracetam, piracetam, clonazepam, propranolol, vitamin B6, and Ginkgo biloba. Other options, such as botulinum toxin and deep brain stimulation, will also be discussed, and a suggested treatment algorithm is provided. While these agents are reasonable treatment options at this time there is a need, with a concerted effort between neurology and psychiatry, for full-scale drug development, including multicenter, randomized, blinded trials to confirm the effectiveness of the agents that were positive in phase 2 trials and the development of newer ones.

Treatment of neurolept-induced tardive dyskinesia

Tardive dyskinesia (TDK) includes orobuccolingual movements and "piano-playing" movements of the limbs. It is a movement disorder of delayed onset that can occur in the setting of neuroleptic treatment as well as in other diseases and following treatment with other drugs. The specific pathophysiology resulting in TDK is still not completely understood but possible mechanisms include postsynaptic dopamine receptor hypersensitivity, abnormalities of striatal gamma-aminobutyric acid (GABA) neurons, and degeneration of striatal cholinergic interneurons. More recently, the theory of synaptic plasticity has been proposed. Considering these proposed mechanisms of disease, therapeutic interventions have attempted to manipulate dopamine, GABA, acetylcholine, norepinephrine and serotonin pathways and receptors. The data for the effectiveness of each class of drugs and the side effects were considered in turn.