Introduction
Rubral tremor(also known as Holmes tremor) is a hyperkinetic movement disorder characterized by low frequency tremor (below 4.5Hz), combination of rest, action and postural tremors and generally specific to an upper area of the body. Rubral tremor occurs after demage to the dopaminergic or non-dopaminergic(cerebellothalamic/cerebelloolivary) systems.
Palatal tremor (previously known as palatal myoclonus) is 1-3Hz rhythmic involuntary movement of the soft palate and is classified into two subtypes. First, essential type has no intracranial pathology and usually affects children. Second, symptomatic type is secondary to lesions of the triangle of Guillain-Mollaret triangle and commonly observed in adults. It has been reported to be assosiated with hypertrophic olivary degeneration(HOD).
Both of these tremors can occur after brainstem or cerebellum lesion, but not many cases have been reported in which a patient has these tremors at the same time. So, this case is aimed to announce a patient with both tremors after cerebellar lesion.
Case presentation
A 69-year-old man was admitted to the emergency room with multiple contusions after falling down. Intraventricular hemorrhage(IVH) was observed by computed tomography(CT)(Fig.1) and immediately underwent midline suboccipital craniectomy, 4th ventricle IVH removal and extraventricular drainage. Moreover, intracranial hemorrhage was also observed on both cerebellum and medulla oblongata. The neurologic examination revealed that the patient had a stuporous mentality and quadriplegia of motor grade I/II. 1 month later, the patient became alert and recovered motor grade of III/III. After 4 months, the patient slipped down in the toilet and intracranial hemorrhage was observed on right cerebellum by CT(Fig.2). After that, the patient gradually developed rubral tremor involving head and both arms and palatal tremor. The tremor of head and both arms showed irregular, low-amplitude, low-frequency(<4.5Hz) at rest, exacerbated with posture and action. Hydrocephalus, especially prominent on 4th ventricle and discrete encephalomalatic changes on both cerebellar hemisphere have been observed gradually. After 10 months, lesion of bilateral dentate nucleus, HOD on both sides were observed on MRI(Fig.3). The patient had botox injection on left medial and lateral pterygoid muscles. After botox injection, amplitude and frequency of tremors has decreased slightly. The tremors decreased significantly after increasing oxcarbazepine from 1T(300mg) to 2T(600mg).
Conclusion
In conclusion, lesion to the cerebellum-brainstem pathway may lead to two distinct tremors. In this case, bilateral rubral tremor and palatal tremor were observed after bilateral cerebellar hemorrhage. There is no specific treatment currently but, successful trials of botulinum toxin injection and medication have been reported in some cases. If a patient shows tremor after brainstem/cerebellum lesion, these tremors should be considered. |
