Myorhythmia

Myorhythmia is a hyperkinetic movement disorder that derives from a disruption of the Triangle of Guillain and Mollaret, due to an identifiable structural lesion. It is often disabling and with disappointing control under medical treatment.

A case of myorhythmia secondary to a vascular insult in the brainstem is reported and an unsuccessful attempt to palliate it with functional neurosurgery.

A 67-year-old man displayed a repetitive, rhythmic, slow 2-3 Hz movement, 6 months after suffering a pontomesencephalic hypertensive hematoma (pontine hemorrhage). The kinetic phenomenon affected the orbicular and low facial muscles, the neck, the thorax and the upper limbs. Furthermore, he exhibited tremors of the soft palate and pendular nystagmus. On T2-weighted magnetic resonance imaging, Hypertrophic olivary degeneration of the inferior olivary nucleus complex was seen. He was diagnosed with secondary myorhythmia and multiple pharmacological treatments were tested but failed. Ultimately, deep brain stimulation with bilateral electrodes placed in the thalamic ventralis intermedius nucleus was offered. Unfortunately, no alleviation of the symptoms was achieved other than mild improvement in involuntary eye movements.

This is the first case to report the use of deep brain stimulation for myorhythmia. A better understanding of the pathophysiology of this condition, and localization of the pacemaker, may allow the identification of reliable neurosurgical therapeutic targets ¹⁾.