Trialing of Intrathecal Baclofen Therapy for Refractory Stiff-Person Syndrome

Abstract

Stiff-person syndrome (SPS) is a rare disorder of the central nervous system characterized by stiffness and muscle spasms that may be progressive in nature. When oral medication is inadequate to control muscle spasticity, intrathecal baclofen may be used. We report a patient with severe SPS and glutamate decarboxylase negative [GAD(-)] (note: GAD(-) indicates the patient has no antibodies to GAD), refractory to oral standard therapies. The patient was effectively trialed with an intrathecal catheter and subsequently treated with chronic intrathecal baclofen, which provided significant relief of spasticity symptoms. A 48-year-old white man with a history consistent with SPS presented to the clinic. His previous history showed that he met several diagnostic criteria for GAD(-) SPS and had a muscle biopsy positive for myositis. Oral medications were unable to control his muscle spasticity, preventing him from working. The patient received an intrathecal trial using a lumbar approach for placement of a thoracic catheter with an initial baclofen dose of 50 μg/d. Gradual titration to symptom relief was performed up to 150 μg/d. Functional evaluation by our physical therapist showed improved motor function, the temporary catheter was removed, and a permanent intrathecal pump placed for intrathecal baclofen infusion. The patient reported excellent symptom relief over the next 6 months and improved activity. Refractory SPS is difficult to treat and has few therapeutic options. We report a GAD(-) patient with SPS and resulting debilitating spasticity that was refractory to oral medications who underwent successful continuous intrathecal catheter trial of baclofen over 4 days and subsequently went on to implantation of intrathecal pump. The literature reports only 5 cases of GAD(-) SPS patients treated with intrathecal baclofen therapy, and these resulted in poor long-term success. Our patient completed a 4-day trial of intrathecal baclofen titrated to effect before pump implantation. We advocate continuous intrathecal trialing, as opposed to single-injection technique, to possibly better determine the effective therapeutic dose and ensure posttrialing successful therapy.