Coma With Absent Brainstem Reflexes and a Burst Suppression on EEG Secondary to Baclofen Toxicity

Abstract

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Baclofen, a muscle relaxant prescribed for the alleviation of symptoms of spasticity acts primarily at the spinal level but with high doses, it penetrates the blood-brain barrier and can result in prominent central nervous depression. Baclofen toxicity has been associated with a variety of symptoms ranging from dizziness to deep coma. We report the clinical course, management, and outcome of a case of baclofen overdose who presented in deep coma with loss of brainstem reflexes and a burst suppression (BS) pattern on his electroencephalogram (EEG). In addition, we reviewed the presentation and outcomes of all reported cases of baclofen toxicity with a BS pattern on EEG to evaluate if those cases share a common clinical presentation and for the presence of signs and symptoms that would help the clinician to consider this diagnosis. There appears to be a common clinical picture associated with severe baclofen toxicity consisting of deep coma associated with loss of all brainstem reflexes including pupillary reactivity, frequent association with seizures/myoclonic jerks, and a BS pattern on EEG. The outcome is generally good, and serial EEGs are recommended to document a reversal of the abnormal electrographic features.

Keywords

• coma
• baclofen toxicity
• burst suppression
• brainstem reflexes
• seizure