Pediatric Neurology 48 (2013) 415e417
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Case Report
Essential Palatal Tremor Treated With Botulinum Toxin Kursat Bora Carman MD a, *, Serhat Ozkan MD b, Coskun Yarar MD a, Ayten Yakut MD a a b
Department of Pediatric Neurology, Eskisehir Osmangazi University Hospital, Eskisehir, Turkey Department of Neurology, Eskisehir Osmangazi University Hospital, Eskisehir, Turkey
article information
abstract
Article history: Received 31 May 2012 Accepted 31 December 2012
Palatal tremor is a rare movement disorder characterized by rhythmic movement of the soft palate. There are two subtypes: essential and symptomatic palatal tremor. Essential palatal tremor is characterized by tinnitus and an absence of other neurological deficits. Different treatment options have been used to treat palatal tremor, with varying success rates. Here we describe a patient with essential palatal tremor and who was treated with botulinum toxin injections. Crown Copyright Ó 2013 Published by Elsevier Inc. All rights reserved.
Introduction
Case Report
Palatal tremor is a rare movement disorder that affects both adults and children. It is a characterized by a rhythmic movement of the soft palate that often causes ear clicking, which may be perceived as tinnitus. Initially, it was commonly referred to as “palatal myoclonus,” but it was subsequently renamed “palatal tremor” at the First International Congress of Movement Disorders in 1990. Palatal tremor can be classified into two groups: essential palatal tremor and symptomatic palatal tremor. Symptomatic palatal tremor is characterized by a lesion of the connections between the nucleus dentatus, the nucleus ruber, and the inferior olivary complex. It is generally develops secondary to brainstem or cerebellar disease. Unlike symptomatic palatal tremor, the pathophysiology of essential palatal tremor is not well understood, and there is an absence of additional neurological deficits are lacking in essential palatal tremor [1]. An important symptom of essential palatal tremor is the presence of tinnitus, which does not occur in symptomatic palatal tremor [2]. Here we describe a patient with essential palatal tremor and who was treated with botulinum toxin injections.
A 9-year-old boy presented with a 2-year history of a noise arising from his throat that was audible by other persons. His birth history, somatic growth and neuromotor development were normal, and he had no history of trauma or neurological disorders. The patient’s parents reported that the ear click decreased or stopped during sleep. He had no difficulty swallowing. A neurological examination revealed that the cranial nerves were intact and the gag reflex was present. The rhythmical palatal movements and high-pitched clicking sound, with a frequency of 160 cycles per minute, were observed (Video 1; supplementary material associated with this article can be found in the online version at http://dx.doi.org/10.1016/j. pediatrneurol.2012.12.035). Laboratory studies were normal, including complete blood count, thyroid tests, liver and renal function tests, and antinuclear antibody studies. The results of tympanometry, audiometry, and brain magnetic resonance imaging were normal. Treatment with antiepileptics such as lamotrigine, levetiracetam and clonazepam, failed. Botulinum toxin (Botox, Allergan) was injected in two different parts (2.5 IU/site) of the tensor veli palatine muscle (Fig 1). The correct needle placement was confirmed by electromyographic guidance. The patient tolerated the injections well; mild nasal regurgitation that developed after the injections resolved completely after 1 week. His symptoms subsided within approximately 2 weeks, and at time of this writing, the patient has been free of symptoms for 10 months.
* Communications should be addressed to: Dr. Carman; Batıkent Mah. Vehbi Dincerler Cad. Sena Apt. No:26 Kat 5 Daire 9; Ibrahimli- Sehitkamil; 27100; Gaziantep; Turkey. E-mail address:
[email protected]
Discussion
The presenting symptom of our patient was tinnitus. Tinnitus is subdivided into subjective tinnitus, which is apparent only to the patient, and objective tinnitus, which can also be heard by others. Objective tinnitus
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Figure 1. Injection sites of botulinum toxin into tensor veli palatini muscle.
has two identified sources: vascular and muscular. Tinnitus of muscular origin may arise from the rhythmic contraction of any of several muscles in the ear and throat. The larger muscles near the eustachian tube, the tensor veli palatine, and the levator veli palatini may contract, causing clicking noises. Essential palatal tremor might be a cause of tinnitus in children, caused by contractions of the tensor veli palatini muscle that opens the eustachian tube, causing a sudden decrease the surface tension within tube [3,4]. On the other hand, symptomatic palatal tremor is caused by a contraction of the levator veli palatini muscle and tinnitus is not common [2]. In clinical practice, the most important difference between essential and symptomatic palatal tremor is the presence of other neurological deficits in symptomatic palatal tremor. Our patient’s only complaint was tinnitus, and his neurological examination and brain magnetic resonance imaging
were normal. In contrast to essential palatal tremor, hypertrophy of the olivary nucleus in symptomatic palatal tremor is an important radiological finding [2]. No definitive treatment has been reported for essential palatal tremor. Anticonvulsants, piracetam, and psychotherapy have all been used with varying success [5]. Botulinum neurotoxin, because of its acetylcholine receptoreblocking capabilities, has been used in therapy for excessive muscular activity in various anatomical regions for more than 20 years. Recently, there have been reports of various new indications (including essential palatal tremor) for botulinum toxin therapy [6-8]. Penney et al. [9] reported the result of botulinum toxin therapy, stating that botulinum toxin BTA might be a first-line therapy. To the best of our knowledge, botulinum toxin has been used in a few pediatric patients with essential palatal tremor. The characteristic features of previous cases are listed in Table 1 [10-15]. Krause et al. [15] compared the differences in outcomes of botulinum toxin therapy for essential palatal tremor between children and adults. Their results showed that botulinum toxin therapy is more effective in pediatric patients, resulting in longer periods of being symptom-free (as long as 4 years). This longlasting therapeutic effect is not explainable with local actions of botulinum toxin. Krause et al. [15] stated that one possible explanation would be the interruption of a peripherally triggered central reentry mechanism. By temporarily disrupting peripheral muscle activity via chemical denervation by botulinum toxin, such a central facilitation would be discontinued and thereby prevented from becoming chronic, irreversible condition. In conclusion; essential palatal tremor is caused by contractions of the tensor veli palatini muscle that opens the eustachian tube. For the treatment of essential palatal tremor, botulinum toxin injections might be used as a treatment, with high success rates and increased quality of life.
Table 1. Characteristics of pediatric patients treated with botulinum toxin
Age Sex Duration EPT side EPT frequency (per min) BT total dose Symptom relief Abbreviations: B ¼ bilateral BT ¼ botulinum toxin EPT ¼ essential palatal tremor IU ¼ international unit MU ¼ mouse unit L ¼ left NA ¼ not available R ¼ right * Botox (Allergan). y Dysport (Ipsen).
Jamieson et al. [10]
Jero et al. [11]
Ensink et al. [12]
Krause et al. [13]
Pal PK et al. [14]
Krause et al. [15]
Krause et al. [15]
17 Male NA Left 80 44 MU* Resolved
12 Female 2 years Right 120 20y IU Resolved
8 Male NA Left 40-180 140* Minimal
10 Female 1 year B (L > R) NA 30* Resolved
8 Male 4 years NA NA 9y Resolved
6 Male 1 year B (R > L) 85 30* MU Resolved
10 Female 1 month L 30 30* Resolved
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Supplementary Material
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