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| ORIGINAL ARTICLE |
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| Year : 2015 | Volume
: 11
| Issue : 5 | Page : 115-117 |
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Risk factors for developing postthymectomy myasthenic crisis in Thymoma Patients
Yueming Wu1, Yipeng Chen2, Hong Liu2, Suhua Zou2
1 Department of Intensive Care Unit, The People's Hospital of Lishui, Lishui 323000; Department of Emergency, The People's Hospital of Lishui, Lishui 323000, PR China
2 Department of Intensive Care Unit, The People's Hospital of Lishui, Lishui 323000, PR China
| Date of Web Publication | 31-Aug-2015 |
Correspondence Address:
Dr. Yipeng Chen
Department of Intensive Care Unit, The People's Hospital of Lishui, Lishui 323000
PR China
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/0973-1482.163863
Objective: The objective of this study is to investigate the risk factors for developing postthymectomy myasthenic crisis in thymoma patients.
Patients and Methods: Patients with thymoma received thymectomy from January 2001 to December 2014 were reviewed and included in this retrospective study in Lishui People's Hospital. Seventy-seven patients were included in this study. For the 77 cases, 66 patients not developing postthymectomy myasthenic crisis were considered as a control group, and other 11 subjects developing postthymectomy myasthenic were considered as the case group. The potential risk factors such age, gender, Osseman stage, Masaoka, pyridostigmine bromide, and et al. were compared between case and control group firstly by Chi-square test or Student's t-test and then by logistic regression test.
Results: Eleven patients developed postthymectomy myasthenic with the incidence of 14.3%; logistic regression analysis indicates that pyridostigmine bromide >360 mg/day administration (OR = 21.2, P < 0.05), postsurgery pulmonary infection (OR = 8.3, P < 0.05) and myasthenic crisis prior surgery (OR = 3.2, P < 0.05) were the independent risk factors for developing postthymectomy myasthenic crisis in thymoma patients.
Conclusion: Thymoma patients with a large dosage of pyridostigmine bromide administration, postsurgery pulmonary infection and myasthenic crisis prior surgery were easy to have postthymectomy myasthenic crisis. Keywords: Logistic regression, postthymectomy myasthenic crisis, risk factors, thymoma
How to cite this article:
Wu Y, Chen Y, Liu H, Zou S. Risk factors for developing postthymectomy myasthenic crisis in Thymoma Patients. J Can Res Ther 2015;11, Suppl S1:115-7 |
| > Introduction | |  |
A thymoma is the most common primary tumor in the anterior mediastinum with the incidence of 1.5 cases/million. [1],[2] Thymoma usually occur in adults with the age range from 40 to 70 which was the relative rate in children and adolescent. Most of the symptom for thymoma is chest pain, cough, and dyspnea. It was reported that about 30-50% of the thymoma patients have myasthenia gravis (MG). [3],[4],[5] And about 10-27% the MG patients had thymoma. [6],[7] Surgery in the import treatment method for thymoma with relative good prognosis. Surgery is recommended for all resectable thymoma in patients who can affordable for the operation. For these resectable patients, the 10 years survival is 70-90%. [8] And postthymectomy myasthenic crisis in a life-threatening complication of MG with a high mortality rate in patients with thymoma. Thus, evaluation the risk factors for postthymectomy myasthenic crisis is useful for health providers to deal with the problem. In this study, we retrospectively analyzed 77 cases with thymoma who underwent the thymectomy and analyzed the independent risk factors for postthymectomy myasthenic crisis by logistic regression.
| > Patients and Methods | | |
Patients with thymoma received thymectomy from January 2001 to December 2014 were reviewed and included in this retrospective study in Lishui People's Hospital. Seventy-seven patients were included in this study. For the 77 cases, 66 patients not developing postthymectomy myasthenic crisis were considered as a control group and other 11 subjects developing postthymectomy myasthenic were considered as the case group. The clinical characteristics and treatment methods were recorded from each of the included patients. The clinical characteristic and treatment methods including age, sex, stages, APACHE II score, pyridostigmine bromide administration dosage myasthenic crisis prior surgery, postsurgery pulmonary infection, postsurgery immunoglobulin usage, and postsurgery plasmapheresis.
Statistics
Statistical analysis was performed using Stata11.0 software (Stata Corporation, College Station, TX, USA). The measurement data is expressed as mean ± standard deviation. The numeration data are expressed by n (%).The Chi-square test and the Student's t-test were used to evaluate the differences in case and control groups. Logistic regression analysis and its 95% confidence interval were used to evaluate the independent risk factors for developing postthymectomy myasthenic crisis. P < 0.05 for two tails was considered significant.
| > Results | | |
General characteristics of the 77 cases
From January 2001 to December 2014 in our hospital database, we included 77 thymoma patients who received thymectomy. Of the 77 cases, 11 were developed postthymectomy myasthenic crisis with the incidence of 14.3%. The mean age of 77 patients were 47.6 ± 10.9 with 34 male and 43 female patients.
Single factor analysis for postoperative myasthenic crisis
The potential risk factors for postoperative myasthenic crisis were evaluated by Chi-square test and the Student's t-test. We find that the patients developing with postthymectomy myasthenic crisis had a larger dosage of pyridostigmine bromide administration (P < 0.05) and lower APACHE II score (P < 0.05) compared with control group. The postsurgery pulmonary infection rate and postsurgery immunoglobulin usage rate were higher in the case group compared with control group (P < 0.05). However, no statistical difference of Osseman stage, Masaoka stage and gender were observed between the two groups (P > 0.05) [Table 1].
Independent risk factors for postoperative myasthenic crisis
The potential risk factors of age, pyridostigmine bromide >360 mg/day, myasthenic crisis prior surgery, APACHE II score, postsurgery pulmonary infection, postsurgery immunoglobulin usage, and postsurgery plasmapheresis were further analyzed by logistic regression. Pyridostigmine bromide >360 mg/day administration (OR = 21.2, P < 0.05), postsurgery pulmonary infection (OR = 8.3, P < 0.05) and myasthenic crisis prior surgery (OR = 3.2, P < 0.05) were found to be the independent risk factors for developing postthymectomy myasthenic crisis in thymoma patients, [Table 2]. | Table 2: Independent risk factors for postoperative myasthenic crisis by logistic regression analysis
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| > Discussion | | |
It was reported that about 65% of young patients will have thymic hyperplasia, and about 15% of all patients may have thymoma. [9] Surgery is recommended for patients with thymoma. Thymectomy is usually carried out after symptom stabilization with plasmapheresis, which is considered to improve outcome from thymic surgery in myasthenic patients. Moreover, it is reported that thymectomy is the only intervention in MG, which offers the realistic prospect of complete remission. [9]
Myasthenic crisis is a life-threatening condition, which is defined as weakness from acquired MG that is severe enough to necessitate intubation or to delay extubation following surgery. Myasthenic crisis is always happened after thymectomy. Several articles have discussed the risk factors for postthymectomy myasthenic crisis. Preoperative history of myasthenic crisis and presence of bulbar symptoms are risk factors associated with postoperative myasthenic crisis after thymectomy. [10] In our study, we find that myasthenic crisis prior surgery is an independent risk factors for postthymectomy myasthenic crisis. Patients with a preoperative history of the myasthenic crisis are 3.2 times higher with postthymectomy myasthenic crisis than patients without a preoperative history of the myasthenic crisis. This result is consistent with Watanabe's study. It is also believed that higher daily dose of pyridostigmine and body mass index predicted worse outcome after surgery. [11] In our retrospective study, we also found that patients administered pyridostigmine bromide >360 mg/day is also related with the postthymectomy myasthenic crisis.
| > Conclusion | | |
Thymoma patients with a large dosage of pyridostigmine bromide administration, postsurgery pulmonary infection and myasthenic crisis prior surgery were easy to have postthymectomy myasthenic crisis. The health provider should pay much attention to this kind of patients in order to make early diagnosis and treatment.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
| > References | | |
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| 7. | Tormoehlen LM, Pascuzzi RM. Thymoma, myasthenia gravis, and other paraneoplastic syndromes. Hematol Oncol Clin North Am 2008;22:509-26. |
| 8. | Detterbeck FC, Parsons AM. Management of stage I and II thymoma. Thorac Surg Clin 2011;21:59-67, vi-vii. |
| 9. | Chaudhuri A, Behan PO. Myasthenic crisis. QJM 2009;102:97-107. |
| 10. | Watanabe A, Watanabe T, Obama T, Mawatari T, Ohsawa H, Ichimiya Y, et al. Prognostic factors for myasthenic crisis after transsternal thymectomy in patients with myasthenia gravis. J Thorac Cardiovasc Surg 2004;127:868-76. |
| 11. | Toker A, Tanju S, Sungur Z, Parman Y, Senturk M, Serdaroglu P, et al. Videothoracoscopic thymectomy for nonthymomatous myasthenia gravis: Results of 90 patients. Surg Endosc 2008;22:912-6. |
[Table 1], [Table 2]
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