Abstracts

Rationale: Baclofen is commonly used to treat spasticity in conditions such as multiple sclerosis. It can have a proconvulsive effect due to its action on postsynaptic GABA-B receptors. We describe a patient who presented with recurrent nonconvulsive status epilepticus (NCSE) due to baclofen overdose. Methods: Case report  Results: A 42 year-old woman with a history of multiple sclerosis presented to our institution on multiple occasions over a period of five years with stereotypic spells of unresponsiveness. During her spells, physical examination showed pinpoint, non-reactive pupils, absent brain stem reflexes, no withdrawal to peripheral or central stimuli, diffuse hypotonia, intermittent flexion posture of all four extremities and sinus bradycardia. EEGs showed frequent generalized epileptiform discharges suggestive of NCSE. Brain MRI showed scattered foci of T2 and FLAIR hyperintensity in the periventricular and subcortical white matter. Extensive testing for routine metabolic and toxic causes, serum/urine organic acids, infectious diseases, autoimmune encephalitis and mitochondrial diseases (including muscle biopsy) were negative. No specific etiology was identified for her spells until 2014, when baclofen levels were measured for the first time. Baclofen had been prescribed to her for spasticity related to multiple sclerosis for the past 6 years. Serum baclofen level was 1.4 mcg/ml (therapeutic range: 0.08 - 0.40 mcg/mL). Urine baclofen level was >3 mcg/ml.  She was treated with anti-epileptic drugs for NCSE and provided supportive care. EEG was continuously monitored. As with her previous spells, she remained unresponsive for a day followed by agitation, screaming, and disorientation for one more day. The EEG normalized in 24 hours and the patient was completely asymptomatic within 48 hours. She later admitted taking an overdose of baclofen prior to this and earlier episodes. Psychiatric evaluation revealed only anxiety related to her medical condition and she did not express suicidal intent. Conclusions: Baclofen overdose should be considered in patients on baclofen therapy who present with unexplained coma and EEG features suggestive of NCSE.  Supportive care, including treatment for NCSE, is associated with a good outcome.  Funding: None