Myorhythmia

Myorhythmia

Myorhythmia is an involuntary movement disorder characterized by rhythmic contraction (1-3 Hz) of muscles producing a coarse tremor, which may affect limbs, face, palate, head, jaw, neck, tongue, eyes or trunk. The movements are continuous and persist during sleep. They are associated with brainstem or thalamic vascular disease, trauma, alcohol-related nutritional deficiency, phenytoin intoxication, Hashimoto’s encephalopathy, paraneoplasia, and Whipple’s disease.
Although very rare, oculomasticatory myorhythmia is of diagnostic importance since it is pathognomonic for Whipple’s disease of the nervous system. Characteristically there is also convergent-divergent pendular nystagmus with synchronous rhythmic movement of the mouth, tongue, jaw and sometimes proximal and distal skeletal muscles. The neurological manifestations of Whipple’s disease are protean, and include dementia, ataxia, supranuclear ophthalmoplegia (with sparing of the pupils), seizures, myoclonus, nystagmus and psychosis. The condition is caused by the bacterium Tropheryma whipplei. Treatment is with antibiotics, usually a two-week intravenous course of trimethoprim-sulphamethoxazole or ceftriaxone followed by oral treatment for one year. Sodium valproate may be helpful for the involuntary movements which do not respond to antibiotics.

References

Anderson M. Neurology of Whipple’s disease. Journal of Neurology,Neurosurgery and Psychiatry 2000; 68: 2-5
Masucci EF, Kurtzke JF, Saini N. Myorhythmia: a widespread movement disorder. Brain 1984; 107: 53-79
Simpson DA, Wishnow R, Gargulinski RB, Pawlak AM. Oculofacialskeletal myorhythmia in central nervous system Whipple’s disease: additional case and review of the literature. Movement Disorders 1995; 10: 195-200

Cross References

Ataxia; Dementia; Myoclonus; Nystagmus