Myoclonic status epilepticus in six patients without epilepsy

Abstract

Myoclonic status epilepticus (MSE) is defined as prolonged period of myoclonic jerks that are correlated with epileptiform discharges on EEG. We here describe clinical features and video-EEG records of six adult patients with MSE who did not have a prior diagnosis of epilepsy. In four out of six patients, MSE was precipitated by drugs. Two out of four patients had chronic renal disease and received beta lactam group antibiotics. Two other patients, who described chronic pain, developed MSE while taking pregabalin. One patient who had dementia and family history of juvenile myoclonic epilepsy (JME) developed MSE one month after quetiapine was introduced. Another patient, who had a recent ischemic stroke, developed MSE due to an unknown reason. In these last two patients, an immediate triggering factor was not evident. Myoclonic status epilepticus ceased in five out of six patients after withdrawal of the drugs and/or intravenous antiepileptic treatment. Myoclonic status epilepticus is a rare event in patients without epilepsy. A correct diagnosis and prompt drug discontinuation may reverse this severe and life-threatening condition.

Keywords: Myoclonic status epilepticus; Photosensitivity; Pregabalin; Renal failure.

Fig. 1

A: EEG recordings from patient 1 on monopolar montage showing very frequent bursts of rapid generalized poly-spikes with normal background activity. Note that myoclonic jerks correlated with spike activities. (X1–X2 and X3–X4 are surface EMG recordings from extensor muscles of the arms) (Calibration: 1 s per between vertical lines, sensitivity 15 μV). B: EEG recordings of patient 1 on monopolar montage. After intravenous injection of 10 mg diazepam, epileptic activity was resolved. (Calibration: 1 s per between vertical lines, sensitivity 15 μV).