EEG changes in intrathecal baclofen overdose: a case report and review of the literature

Abstract

Objective: To review the clinical and EEG manifestations of intrathecal baclofen overdose. Methods: We identified one patient who had received an overdose of intrathecal baclofen. Information about the clinical course was obtained by reviewing the patient's medical record. EEGs were recorded with the use of the standard 10–20 electrode placement system. Results: The patient received 30 mg baclofen intrathecally. Shortly after the injection he developed respiratory insufficiency and quadriparesis and later became comatose. The first EEG obtained 20 h after the injection showed very frequent quasiperiodic generalized epileptiform discharges. The patient gradually improved clinically and a second EEG obtained 24 h later showed only intermittent bursts of generalized slow wave activity. A repeat EEG study 1 week later was normal. Conclusions: The EEG in intrathecal baclofen overdose can show quasiperiodic generalized epileptiform discharges. This does not necessarily indicate the presence of underlying potential epileptogenicity, and treatment with an antiepileptic medication is not necessary.