IVIG Pre-Thymectomy

Abstract & Commentary

Source: Huang CS, et al. Intravenous immunoglobulin in the preparation of thymectomy for myasthenia gravis. Acta Neurol Scand. 2003;108:136-138.

Six consecutive myasthenia gravis patients, one man and 5 women, aged 21-68, underwent intravenous immunoglobulin (IVIG) infusion in preparation for thymectomy. The purpose was to determine, in this unblinded trial, whether IVIG was beneficial to outcome. No one was in myasthenic crisis nor had any functional pulmonary impairment. Mean disease duration was approximately 7 months (range, 2-17 months), and diagnosis was based on clinical, electromyographic, and acetylcholine receptor antibody criteria. Pyridostigmine had been the only preoperative medication prior to the IVIG, which was infused over 5 days at a dose of 0.4 mg/kg/d. Transternal thymectomy was performed in all.

All patients benefited from IVIG within a mean of 3.33 days (range, 1-9 days). Pyridostigmine requirements decreased, thymectomy was performed within a mean of 11 days (range, 9-13), and the postoperative courses were uneventful with extubation successfully undertaken by 8 hours (mean, 6.7 hours). Reintubation was never required. Improvement was sustained post-operatively for 2 weeks in all patients and for 6 and 10 weeks in 4 and 3 cases, respectively. One patient who initially improved preoperatively with IVIG deteriorated and required plasma exchange prethymectomy. None of the remainder required plasma exchange, steroids, or immunosuppressants pre- or postoperatively. IVIG appears safe and effective in the preoperative preparation for thymectomy. Larger controlled trials comparing IVIG to plasma exchange would be the logical next step in confirming and extending these results.

Commentary

Thymectomy, though widely recommended for the treatment of autoimmune myasthenia gravis, remains a treatment without controlled prospective studies to support its role. Such a trial, comparing immunosuppression with and without thymectomy, has been recommended by the American Academy of Neurology and is being developed.

Thymectomy may be performed by various techniques. Transcervical thymectomy, even without removal of all the cervical and mediastinal perithymic fat, is felt by some, based on retrospective study, to be comparable to transternal thymectomy.1 Others report, again based on retrospective data, that partial sternotomy with removal of the entire thymus and the surrounding fat yields results "similar to the literature data."2 Close examination of the data, however, does not support these conclusions.3 Life-table analysis indicates that combined transternal and transcervical thymectomy produces greater remission rates than any of the above methods (ibid). Prospective study comparing the different techniques is desirable and warranted. Although randomized study would make recruitment difficult, a prospective, nonrandomized study is a doable and attractive alternative. — Michael Rubin, MD, Professor of Clinical Neurology, New York Presbyterian Hospital-Cornell Campus, Assistant Editor, Neurology Alert.

References

1. Shrager JB, et al. Ann Thorac Surg. 2002;74:320-327.

2. Pego-Fernandes PM, et al. Ann Thorac Surg. 2002;74:204-208.

3. Jaretzki A 3rd, et al. Ann Thorac Surg. 2003;76:1-3.