[Anesthetic management for thymectomy in a patient with stiff-person syndrome].

Stiff-person syndrome is an autoimmune disease characterized by muscle rigidity accompanied by decreased respiratory function. We report a patient with this syndrome who underwent thymectomy under general anesthesia. A 79-year-old woman complaining of increasing muscle rigidity over the past four months was transferred to this hospital. Marked speech disturbance and dysphagia were observed on admission. The diagnosis of stiff-person syndrome was made based on an increase in serum anti-glutamic acid decarboxylase antibody level and thymoma in the anterior mediastinum. Following alleviation of muscle rigidity by high-dose gamma-globulin, thymectomy was scheduled. General anesthesia was given with propofol, fentanyl and epidural ropivacaine. Propofol was continuously infused to maintain BIS below 60 and vecuronium was intermittently administered when muscle contraction was observed in response to electrical stimulation of the ulnar nerve. Despite full recovery of muscle contractility following surgery, tidal volume was too low to remove the tracheal tube, and mechanical ventilation was continued in ICU. One hour after admission to ICU, the tracheal tube was removed, with no marked changes in respiratory condition thereafter. Since many anesthetics are respiratory suppressants that can delay the recovery of respiratory function, careful monitoring of respiratory condition is required postoperatively.