Oromandibular dystonia – A systematic review

Oromandibular Dystonia as a Side Effect of Methotrexate

Oromandibular dystonia is a focal dystonia characterized by involuntary movements of the jaw, oropharynx, lips, and tongue. The diagnosis of oromandibular dystonia is clinical and can be complex. For effective treatment, it is essential to understand its underlying etiology. A 70-year-old man was referred to our center with a diagnosis of Meige's syndrome, which had been present for five and a half years, for receiving botulinum toxin-A (BoNT-A) injections. Upon physical examination, he exhibited oromandibular dystonia, with a score of 177 points on the Oromandibular Dystonia Rating Scale (OMDRS). He had a history of taking methotrexate for six years, as he was diagnosed with psoriatic arthritis during that time. The possibility of methotrexate-induced dystonia was considered. A switch from methotrexate to sulfasalazine was initiated. Subsequently, the patient showed progressive improvement in his symptoms, as reflected by an OMDRS score of 103 points. After eight weeks, the medical team decided to supplement the treatment with BoNT-A injections, resulting in an OMDRS score of 75. While there is currently no definitive evidence linking the use of methotrexate to the development of dystonia, it is advisable to consider oromandibular dystonia as a potential side effect of methotrexate until more robust evidence becomes available.

Botulinum toxin for motor disorders

Botulinum neurotoxins are a group of biological toxins produced by the gram-negative bacteria Clostridium botulinum. After intramuscular injection, they produce dose-related muscle relaxation, which has proven useful in the treatment of a large number of motor and movement disorders. In this chapter, we discuss the utility of botulinum toxin treatment in three major and common medical conditions related to the dysfunction of the motor system, namely dystonia, tremor, and spasticity. A summary of the existing literature is provided along with different techniques of injection including those recommended by the authors.

Effects of Botulinum Toxin Therapy on Health-Related Quality of Life Evaluated by the Oromandibular Dystonia Rating Scale

Oromandibular dystonia (OMD) refers to a focal dystonia in the stomatognathic system. Health-related quality of life (HRQoL) in isolated dystonia is associated with non-motor symptoms such as depression, anxiety, and pain, as well as motor symptoms. To evaluate HRQoL in patients with OMD, the therapeutic effects of botulinum neurotoxin (BoNT) therapy were assessed using a recently developed and validated comprehensive measurement tool called the Oromandibular Dystonia Rating Scale (OMDRS). Altogether, 408 patients (jaw closing dystonia, n = 223; tongue (lingual) dystonia, n = 86; jaw opening dystonia, n = 50; jaw deviation dystonia, n = 23; jaw protrusion dystonia, n = 13; and lip (labial) dystonia, n = 13) were evaluated at baseline and after the end of BoNT therapy or in a stable status. The total OMDRS score reduced significantly from 149.1 to 57.6 (p < 0.001). Mean improvement was 63.1%. All examiner-rated subscales (severity, disability, and pain) and patient-rated questionnaire scores (general, eating, speech, cosmetic, social/family life, sleep, annoyance, mood, and psychosocial function) were significantly lower at the endpoint than at baseline (p < 0.001). The BoNT injection had a highly positive impact on patient HRQoL, and the OMDRS could evaluate both motor phenomena and non-motor symptoms.

Botulinum Toxin Therapy for Oromandibular Dystonia and Other Movement Disorders in the Stomatognathic System

Various movement disorders, such as oromandibular dystonia, oral dyskinesia, bruxism, functional (psychogenic) movement disorder, and tremors, exist in the stomatognathic system. Most patients experiencing involuntary movements due to these disorders visit dentists or oral surgeons, who may be the first healthcare providers. However, differential diagnoses require neurological and dental knowledge. This study aimed to review scientific advances in botulinum toxin therapy for these conditions. The results indicated that botulinum toxin injection is effective and safe, with few side effects in most cases when properly administered by an experienced clinician. The diagnosis and treatment of movement disorders in the stomatognathic system require both neurological and dental or oral surgical knowledge and skills, and well-designed multicenter trials with a multidisciplinary team approach must be necessary to ensure accurate diagnosis and proper treatment.

Patient selection and injection techniques for botulinum neurotoxin in oromandibular dystonia

•

Botulinum toxin is considered as the first-line therapy in oromandibular dystonia (OMD) by most experts and evidence-based literature.

•

Oromandibular dystonia (OMD) can be classified into several subtypes so primary muscle involvements can be identified for botulinum toxin (BoNT) injections.

•

This review article aims to provide a framework for practical clinical approaches in patients with OMD for BoNT injections.

•

Careful stepwise planning is recommended to identify primary muscles responsible and employ a conservative approach to dosing titration.

•

Treating physicians should be diligent to observe for adverse events as muscles involved in OMD are small, delicate and situated in close proximity.

Oromandibular dystonia (OMD) is a form of focal dystonia that involves the masticatory, lower facial, labial, and lingual musculature. It is a disabling disorder which had limited treatment options until the recent introduction of botulinum toxin (BoNT) as the recommended first-line therapy by most experts and evidence-based literature. Owing to the complex relationship between the muscles of mastication and surrounding muscles, there is a wide variety of dynamic clinical presentations, making clinical recognition and the corresponding approach to BoNT injection therapy difficult. In this review, the authors provide a framework for practical clinical approaches, beginning with the recognition of clinical subtypes of OMD (jaw-opening, jaw-closing, jaw-deviating, lingual, peri-oral, and/or pharyngeal dystonias), followed by patient selection and clinical evaluation to determine function interferences, with injection techniques illustrated for each subtype. Careful stepwise planning is recommended to identify the muscles that are primarily responsible and employ a conservative approach to dosing titration. Treating physicians should be diligent in checking for adverse events, especially for the first few injection cycles, as muscles involved in OMD are small, delicate, and situated in close proximity. It is recommended that future studies should aim to establish the clinical efficacy of each subtype, incorporating muscle targeting techniques and patient-centred outcome measures that are related to disturbed daily functions.