Myasthenia Gravis Appearing After Thymectomy: a Case Report and Review of the Literature

A small proportion of thymoma patients without myasthenia gravis (MG) have been observed to develop MG after total removal of the thymoma. However, the underlying cause is not yet known due to the rarity of postoperative MG patients. We report a 39-year-old man in whom MG appeared after surgical removal of a thymoma. Computed tomography and magnetic resonance imaging showed no signs of recurrent or metastatic thymoma. Administration of pyridostigmine bromide resulted in the prompt improvement of myasthenic symptoms. Our observations indicate that postoperative follow-up care with monitoring of possible postoperative MG is necessary after resecting a thymoma.     

电视胸腔镜辅助胸腺切除术

目的探讨电视胸腔镜辅助胸腺切除的临床应用价值. 方法 2002年9月～2004年6月,18例胸腺疾病和重症肌无力(myasthenia gravis,MG)行胸腔镜辅助下胸腺切除手术,其中胸腺全切7例,11例MG行胸腺扩大切除. 结果 17例在胸腔镜辅助下完成, 1例中转小切口(7 cm)开胸手术.3例MG术后须短暂呼吸机辅助通气(<12 h),二次气管插管1例,余无严重并发症,无手术死亡.手术时间47～115 min,平均95 min;胸腔引流时间1.2～2.6 d,平均2 d;术后住院时间4～9 d,平均5.5 d.9例良性胸腺瘤或胸腺囊肿随访3～20个月,平均13个月,无复发.11例MG随访3～19个月,平均10个月,4例症状完全缓解,7例都分缓解. 结论胸腔镜辅助下胸腺切除手术,具有创伤小、恢复快等优点,胸腔镜下胸腺扩大切除治疗重症肌无力在技术上是可行的.     

电视胸腔镜胸腺切除治疗重症肌无力症

目的探讨电视胸腔镜手术(video-assisted thoracoscopic surgery,VATS)胸腺切除治疗重症肌无力症(myasthenia gravis,MG)的可行性. 方法 18例MG采用VATS经右胸前侧径路行胸腺切除联合纵隔脂肪清扫. 结果 17例顺利完成手术,1例因电凝钩伤及左头臂静脉干而中转开胸止血.平均手术时间105 min,术中失血量平均80 ml.全组无术后死亡及危象发生.18例随访1～20个月,平均11.3个月.按Osserman疗效评价,缓解5例(27.8%),明显改善6例(33.3%),部分改善4例(22.2%),无变化3例(16.7%),有效率83.3%(15/18). 结论 VATS经右胸前侧径路行完全胸腺切除可行,且具有创伤小、恢复快等优点.     

Ontogeny and thymus-dependence of T cell surface antigens in Xenopus : flow cytometric studies on monoclonal antibody-stained thymus and spleen

Recently generated anti-Xenopus T cell monoclonal antibodies (mAbs) to the 120 kDA XTLA-1 determinant and against the putative CD5 and CD8 homologues, together with anti-IgM and anti-MHC class II mAbs, are used in dual colour flow cytometric experiments to characterize cell surface antigenic expression on lymphocytes in thymus and spleen of Xenopus laevis during larval and early adult life and also in metamorphosis-inhibited animals. Histological confirmation of T cell emergence early in larval ontogeny is supplied by cryostat sections stained for CD8. Five-day thymectomy i.e. prior to T-lineage cell differentiation in the thymus, abolishes T cell marker expression in the spleen for up to 1 year. Moreover, late larval (20 days) or early adult (3 months) thymectomy (i.e. removal after peripheralization of T cells has occurred) also leads to severe depletion of mAb-defined T cells in the spleen.     

重症肌无力术后延长拔管时间的临床价值

目的　探讨重症肌无力 (MG)胸腺切除术后 ,延长气管拔管时间 ,减少气管切开的价值。方法　回顾分析 1978年至 2 0 0 2年 12月行MG胸腺切除 2 36例 ,按时间分A组 :1996年 12月以前手术者116例 ,对术后可能发生肌无力危象的高危因素病人施行预防性气管切开 ;B组 :1997年后手术 12 0例 ,对具发生危象高危因素者采用延长气管拔管时间 ,并对两组危象发生率及气管切开率进行比较。结果　全组发生危象 4 4例 (18 6 % ) ,气管切开 4 6例 (ARDS 1例除外 )占 19 5 %。其中A组发生危象 2 3例(19 8% ) ,气管切开 34例 (2 9 3% ) ;B组发生危象 2 1例 (17 5 % ) ,气管切开 12例 (10 % )。两组危象发生率无明显差异 ,但A组的气管切开率明显高于B组 (P <0 0 0 1)。结论　对MG胸腺切除术后具发生危象高危因素病人 ,采用延长气管插管时间及辅助通气 ,可显著减少气管切开率。     

Splenocyte response to T cell-derived cytokines in thymectomized Xenopus.

A miniaturized, “hanging-drop” bioassay reveals that splenocytes from earlythymectomized (Tx) Xenopus can respond (by enhanced thymidine incorporation) to thymicdependent “cytokines” generated in PHA- or alloantigen-stimulated cultures. Preliminary evidence, using fluorescence activated cell sorting, indicates that surface IgM⁻ splenocytes, rather than sIgM⁺ cells, from Tx toads are sensitive to the crude, splenocyte-derived, active supernatants. Although these responsive cells display residual, but low, reactivity to PHA, their thymus independence is suggested by flow cytometric observations using the anti-T cell monoclonal antibody XT-1. The development of “T-like” cells in Tx Xenopus is discussed.     

Treatment of myasthenia gravis

Summary In the treatment of myasthenia gravis (MG) considerable progress has recently been achieved. Our experience is based on the observation of 139 patients with an average follow-up of 3 years and 4 months.A treatment plan and results are presented.Indications for thymectomy: all cases of MG in adult life, apart from ocular myasthenia without radiological thymoma and without electrophysiological and pharmacological signs of generalization; before puberty only cases with radiological thymoma and severely incapacitating or life-threatening signs.Median sternotomy is preferable for thymoma, the transcervical approach with a sternal split for non-neoplastic thymus. Mediastinal radiotherapy is indicated after removal of an invasive or adhesive thymoma.Indications for corticosteroids: 1) before thymectomy: respiratory weakness; 2) soon after thymectomy: life-threatening signs; 3) later after thymectomy: incapacitating or life-threatening signs; 4) as an alternative to thymectomy: when surgery cannot be performed or it is not indicated. Oral Prednisone was nearly always preferred: alternate-day high single dose (75 to 115 mg) has given good results in most cases even if in some cases a small dose was required in the off day; inversely a lower alternate-day or daily dose was often sufficient.Long-term results: following this schedule for adult patients good results were scored in 67% of thymomas, in 94% of hyperplasias, and in 62% of unthymectomized patients: in prepuberal life the few cases of severe MG have all shown a favorable evolution.

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Zusammenfassung Bei der Behandlung der Myasthenie wurden in letzter Zeit beachtliche Fortschritte erzielt. Wir teilen hier unsere Erfahrungen anhand von 139 Patienten mit einer durchschnittlichen Katamnese von 3 Jahren und 4 Monaten mit.Wir betrachten als Indikationen für eine Thymektomie: alle Fälle von Myasthenie beim Erwachsenen mit Ausnahme der rein okulären Formen ohne radiologisch nachweisbares Thymom und ohne elektrophysiologische oder pharmakologische Zeichen einer Generalisierung; bei Kindern vor der Pubertät empfehlen wir die Thymektomie nur in Fällen mit radiologisch nachweisbarem Thymom und mit schwerer Beeinträchtigung oder gar Lebensgefährdung durch die Symptome.Die mediane Sternotomie ist beim Thymom vorzuziehen, der transzervikale Zugang mit Spaltung des Sternums für die nicht neoplastischen Thymusvergrößerungen. Mediastinale Strahlentherapie ist nach Exstirpation eines invasiven Thymoms oder eines Thymoms mit Adhäsionen angezeigt.Als Indikation für die Corticosteroidtherapie betrachten wir: 1. wenn vor der Thymektomie Atemstörungen bestehen; 2. wenn bald nach der Thymektomie lebensbedrohliche Symptome auftreten; 3. wenn später nach Thymektomie nennenswert behindernde oder lebensbedrohliche Symptome in Erscheinung treten; 4. als Alternative zur Thymektomie, wenn diese nicht durchgeführt werden kann oder nicht indiziert ist. Die orale Prednisontherapie wurde fast immer vorgezogen: wir gaben an alternierenden Tagen jeweils hohe Einzeldosen (75–115 mg) mit gutem Erfolg in den meisten Fällen. In gewissen Fällen war eine kleine Dosis an den Tagen zwischen der Hauptdose aber genügend, ebenso in Einzelfällen eine allgemein niedrigere Dosierung. Die Langzeiterfolge mit diesem therapeutischen Vorgehen betrugen 67% gute Ergebnisse bei Thymomen und 94% bei Thymushyperplasie. Unter den nicht thymektomierten Patienten wiesen 62% ein gutes Ergebnis auf. Vor der Pubertät zeigten die allerdings wenigen Fälle schwerer Myasthenie alle ein gutes Ansprechen auf die Therapie.

     

A Decrease in the Percentage of CD3+ Cells Is Correlated With Clinical Improvement During Plasmapheresis in Patients With Myasthenia Gravis

Plasmapheresis not only removes circulating antibodies but also modulates cellular immunity, including lymphocyte subsets. To investigate the effect of double‐filtration plasmapheresis (DFPP) on the ratio of lymphocyte subsets in patients with myasthenia gravis (MG), we examined the percentages of B‐cells, T‐cells, T helper (Th) cells, T suppressor (Ts) cells, natural killer (NK) cells, NKT cells, and Th/Ts ratio before and after a single DFPP session and after a course of DFPP. A total of 26 patients were recruited; their peripheral blood lymphocyte subsets were assayed using flow cytometry. After a single session of DFPP treatment, the percentages of T‐cells (P = 0.0200), Th cells (P = 0.0178), and the Th/Ts ratio (P = 0.0309) decreased significantly, whereas the percentage of NK cells (P = 0.0007) increased significantly. More importantly, after one course of DFPP treatment, the reduced clinical quantitative MG (QMG) score was correlated with the decrease of the percentage of T‐cells (r = 0.5005, P = 0.0092). Fourteen thymectomized MG patients had decreased percentages of T‐cells (P = 0.0304) and Th cells (P = 0.0444), whereas they had increased NK cells (P = 0.0197) after a single DFPP session. Here, transiently decreased percentages of T‐cells after the full DFPP course could enhance the effectiveness of plasmapheresis for MG patients.