Thymectomy for Myasthenia Gravis: Prognostic Factors in 70 Patients

Incidence of thymoma in myasthenia gravis: a systematic review

Background and Purpose

Myasthenia gravis (MG) is usually comorbid with thymoma. More accurate estimates of the incidence thymoma in MG will help inform patients and their physicians, facilitate health policy discussions, provide etiologic clues, and optimize the management of MG.

Methods

We conducted a systematic review search of relevant English-language studies published between 1960 and 2012 using MEDLINE and Embase. We identified additional studies by reviewing the bibliographies of the retrieved articles and hand searched the main neurology journals. Only incidence studies and case series of unselected MG patients in which information about thymoma were included.

Results

Out of 2206 potentially relevant studies, 49 met the inclusion criteria. Although there was a considerable degree of heterogeneity, the pooled estimate of the incidence of thymoma in MG was 21% (95% confidence interval, 20-22%). The pooled incidence was significantly higher for surgery-based studies than for population- and hospital-based studies. A large proportion of the reported thymomas were noninvasive. Furthermore, thymoma appears to occur significantly more frequently among male MG patients and those older than 40 years at the onset of MG.

Conclusions

Thymoma is common in MG patients, but appears to be found more often in male MG patients and those older than 40 years at the onset of MG. Further research is needed to expand our understanding of these association conditions.

Critical care of myasthenia gravis in a resource poor setting: a study of South East Nigeria

BACKGROUND

Myasthenia gravis presenting as a neurologic emergency warrants management in a critical care unit. In resource poor settings which typify much of Africa, this can be very challenging even in tertiary centers with consequently unfavorable outcomes.

AIM

This study evaluated the outcomes of intensive care management of patients with myasthenia gravis in a regional teaching hospital in South East Nigeria.

METHODS

A retrospective study was undertaken of patients admitted into the intensive care unit of the University of Nigeria Teaching Hospital Enugu, South East Nigeria, with myasthenia gravis as a neurologic emergency. This study covered a 13-year period from 1992 to 2004. From the case records demographic data, clinical features and details of clinical management, complications, and outcomes were determined and subjected to analysis.

RESULTS

The median age at presentation was 29 years (range, 20 to 42 y) with male:female ratio of 1:2.7. The median duration of illness before presentation to the intensive care unit was 7 months (range, 1 wk to 3 y). The median duration of stay in the unit was 15 days (range, 1 to 36 d). Two cases of septicemia and acute renal failure were recorded. The overall mortality rate was 27.3%.

CONCLUSION

Sepsis is a major factor contributing to poor outcomes among patients with myasthenia gravis managed in critical care units in Nigeria. Vigorous and concerted efforts should be made to make intensive care units more effective in Africa.

Robotic-assisted thymectomy

Thymectomy is an established therapy for myasthenia gravis. Minimally invasive surgery for thymectomy has been reported, but not clearly shown to be equivalent to open resection. Robotic-assisted thymectomy may provide the benefit of a full resection of thymic tissue and anterior mediastinal tissue for the treatment of myasthenia gravis by a minimally invasive approach. We present a review of the experience of robotic thymectomy.