[Myoclonus as a manifestation of respiratory encephalopathy]

The triad of mental abnormalities, neurologic disorders and abnormal electroencephalogram is central to respiratory encephalopathy. The development of myoclonus has been considered as a sign heralding the development of generalized seizures and coma. A patient with chronic bronchitis is reported in whom myoclonus was the predominant symptom. Myoclonus was generalized, symmetrical and synchronic, and electroencephalographic correlation was shown, with diffuse polyspike-high potential wave discharges coincident with myoclonus. Remarkably, they promptly responded to low doses of diazepam, with disappearance of clinical neurologic and electrical findings. These have not subsequently relapsed although the patient is not receiving specific therapy. The risk of the administration of diazepam was weighted against other specific drugs (clonacepam, pyracetam) which are probably better tolerated. The interest in the quicker response of diazepam prevailed. We propose the inclusion of myoclonus secondary to respiratory encephalopathy in the classification of myoclonic disorders.