Anesthetic Implications in Stiff-Person Syndrome

Abstract

A 46-yr-old female presented to the operating room for repair of an intrathecal baclofen pump. Her diagnosis of SPS was based on clinical presentation and the presence of an autoantibody against the central nervous system enzyme glutamic acid decarboxylase (GAD). The syndrome began as muscle stiffness in her lower extremities and insidiously progressed to a state of constant stiffness resulting in permanent contractures of her lower extremities and moderate rigidity of her upper extremities. The patient’s facial, cervical, and extraocular muscles were spared. When startled by a loud noise, the patient experienced a painful brisk spasm resulting in opisthotonic posturing. These acute exacerbations were treated with a 50-mg dose of diazepam administered intramuscular. Other pharmacologic therapies included intrathecal baclofen and 100 mg of diazepam orally per day. Past surgical history was significant for a 2-day history of prolonged postoperative weakness after the baclofen pump was inserted, and an overdose of baclofen was suggested as the cause. A review of the previous anesthetic record revealed that propofol and succinylcholine followed by desflurane was used for induction of anesthesia, tracheal intubation, and maintenance of anesthesia, respectively. Anesthesia was induced with sufentanil 10 pg, thiopental 375 mg (5.8 mg/kg), and vecuronium 8 mg (0.12 mg/kg) administered intravenously (IV). It was inferred from the slow and inadequate induction of anesthesia that the IV catheter had infiltrated subcutaneously although visual inspection was equivocal. A facial nerve train-of-four twitch monitor indicated an absence of all four twitches 10 min after induction of anesthesia. Inhalation anesthesia via a