Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + At a Glance Download Section PDF Listen ++ A very rare genetic disorder characterized by predominant neurological syndrome with alteration of cerebellum and globus pallidus. Muscular functions can also be affected. + Synonym Download Section PDF Listen ++ Myoclonus and Ataxia Syndrome. + Genetic Inheritance Download Section PDF Listen ++ Autosomal dominant, heterogeneous. + Pathophysiology Download Section PDF Listen ++ Neurological lesions or anomalies are often observed (cerebellar dentate nucleus, degeneration of globus pallidus, elevated cerebrospinal fluid uric acid); muscle biopsy shows the presence of ragged red fibers that probably are caused by mitochondrial abnormalities, which could explain the pathophysiology of this syndrome. Controversy exists about considering Ramsay Hunt Syndrome as a specific entity. + Diagnosis Download Section PDF Listen ++ Association of myoclonus ataxia and occasional seizures. + Clinical Aspects Download Section PDF Listen ++ Neurological signs are isolated. No other association is known. Myoclonus, cerebellar ataxia, intention tremor, and occasional tonic-clonic seizures are the only symptoms. + Precautions before Anesthesia Download Section PDF Listen ++ Evaluate the neurological repercussion. Evaluate muscular status especially for the presence of myoclonic tone. Verify ability of patients to use patient-controlled analgesia if necessary. + Anesthetic Considerations Download Section PDF Listen ++ The presence of epilepsy must be considered and medication known to stimulate convulsions (e.g., sevoflurane) should be avoided. + Pharmacological Implications Download Section PDF Listen ++ The antiepileptic medication must be continued until the morning of surgery. Avoid succinylcholine in presence of muscular abnormalities and potential risk (undocumented) of hyperkalemic response. Avoid enflurane, methohexital, and hypnomidate because of seizure. + Other Conditions to Be Considered Download Section PDF Listen ++ Juvenile Paralysis Agitans of Hunt: Autosomal dominant. This syndrome is characterized by mask-like facies, parkinsonism, tremor, bradykinesia, dysarthria, rigidity, gait disturbance, and flexion dystonia of fingers. Progression is slow. Onset in teens or earlier. ++ Dyssynergia Cerebellaris Myoclonica of Hunt (Cerebelloparenchymal Disorder V, Spinodentate Atrophy): Autosomal recessive with ataxia, myoclonic jerks, dentate neuron loss superior, and cerebellar peduncle fiber loss. + References Download Section PDF Listen ++Bomont P, Watanabe M, Gershoni-Barush R, et al: Homozygosity mapping of spinocerebellar ataxia with cerebellar atrophy and peripheral neuropathy to 9q33-34, and with hearing impairment and optic atrophy to 6p21-23. Eur J Hum Genet 8(12):986, 2000. [PubMed: 11175288]