Transsternal Maximal Thymectomy is Effective for Extirpation of Cervical Ectopic Thymic Tissue in the Treatment of Myasthenia Gravis

PURPOSE: Extensive extirpation of cervico-mediastinal adipose tissue increases the chance of removing ectopic thymic tissues, thus potentially improving the prognosis of myasthenia gravis after thymectomy. We sought to increase efficacy and safety of transsternal maximal thymectomy (TSMT). MATERIALS AND METHODS: Twenty four patients who underwent TSMT from July 2006 to June 2007 were retrospectively reviewed and compared with 73 patients who underwent transsternal extended thymectomy (TSET) from January 2004 to May 2006. Ectopic thymic tissue in additionally excised cervicomediastinal fat tissue was examined histologically. RESULTS: In TSMT group, operation time, amount of cumulative drainage and duration of drainage were significantly higher than TSET group. However, the difference in hemoglobin count, amount of transfusion, duration of intensive care, postoperative hospital stay, and complication rates were not statistically different. There was no operative mortality in either group. Ectopic thymic tissue was found in 50% of patients. All patients had ectopic thymic tissues in the cervical area. Two patients had additional ectopic tissue in the aortopulmonary window, and 1 patient had ectopic tissue at posterior of the left bracheocephalic vein and lateral of the right phrenic nerve. CONCLUSION: TSMT is more effective in the extirpation of ectopic thymic tissues than TSET without significant impairment of safety, especially in the cervical area.ope

An occasional diagnosis of myasthenia gravis - a focus on thymus during cardiac surgery: a case report

<p>Abstract</p> <p>Background</p> <p>Myasthenia gravis, an uncommon autoimmune syndrome, is commonly associated with thymus abnormalities. Thymomatous myasthenia gravis is considered to have worst prognosis and thymectomy can reverse symptoms if precociously performed.</p> <p>Case report</p> <p>We describe a case of a patient who underwent mitral valve repair and was found to have an occasional thymomatous mass during the surgery. A total thymectomy was performed concomitantly to the mitral valve repair.</p> <p>Conclusion</p> <p>The diagnosis of thymomatous myasthenia gravis was confirmed postoperatively. Following the surgery this patient was strictly monitored and at 1-year follow-up a complete stable remission had been successfully achieved.</p

Myasthenia gravis

Myasthenia gravis (MG) is a rare, autoimmune neuromuscular junction disorder. Contemporary prevalence rates approach 1/5,000. MG presents with painless, fluctuating, fatigable weakness involving specific muscle groups. Ocular weakness with asymmetric ptosis and binocular diplopia is the most typical initial presentation, while early or isolated oropharyngeal or limb weakness is less common. The course is variable, and most patients with initial ocular weakness develop bulbar or limb weakness within three years of initial symptom onset. MG results from antibody-mediated, T cell-dependent immunologic attack on the endplate region of the postsynaptic membrane. In patients with fatigable muscle weakness, the diagnosis of MG is supported by: 1. pharmacologic testing with edrophonium chloride that elicits unequivocal improvement in strength; 2. electrophysiologic testing with repetitive nerve stimulation (RNS) studies and/or single-fiber electromyography (SFEMG) that demonstrates a primary postsynaptic neuromuscular junctional disorder; and 3. serologic demonstration of acetylcholine receptor (AChR) or muscle-specific tyrosine kinase (MuSK) antibodies. Differential diagnosis includes congenital myasthenic syndromes, Lambert Eaton syndrome, botulism, organophosphate intoxication, mitochondrial disorders involving progressive external ophthalmoplegia, acute inflammatory demyelinating polyradiculoneuropathy (AIDP), motor neuron disease, and brainstem ischemia. Treatment must be individualized, and may include symptomatic treatment with cholinesterase inhibitors and immune modulation with corticosteroids, azathioprine, cyclosporine, and mycophenolate mofetil. Rapid, temporary improvement may be achieved for myasthenic crises and exacerbations with plasma exchange (PEX) or intravenous immunoglobulin (IVIg). Owing to improved diagnostic testing, immunotherapy, and intensive care, the contemporary prognosis is favorable with less than five percent mortality and nearly normal life expectancy

Myasthenia gravis and pregnancy: clinical implications and neonatal outcome

BACKGROUND: The myasthenia gravis is twice as common in women as in men and frequently affects young women in the second and third decades of life, overlapping with the childbearing years. Generally, during pregnancy in one third of patients the disease exacerbates, whereas in two thirds it remains clinically unchanged. Complete remission can occur in some patients. METHODS: To describe the clinical course, delivery and neonatal outcome of 18 pregnant women with the diagnosis of myasthenia gravis. Retrospective chart review of pregnant patients with myasthenia gravis, followed at the National Institute of Perinatology in Mexico City over an 8-year period. Data was abstracted from the medical records on the clinical course during pregnancy, delivery and neonatal outcome. RESULTS: From January 1, 1996 to December 31, 2003 18 patients with myasthenia gravis were identified and included in the study. The mean ± SD maternal age was 27.4 ± 4.0 years. During pregnancy 2 women (11%) had an improvement in the clinical symptoms of myasthenia gravis, 7 women (39%) had clinical worsening of the condition of 9 other patients (50%) remained clinically unchanged. Nine patients delivered vaginally, 8 delivered by cesarean section and 1 pregnancy ended in fetal loss. Seventeen infants were born at mean ± SD gestational age of 37.5 ± 3.0 weeks and a mean birth weight of 2710 ± 73 g. Only one infant presented with transient neonatal myasthenia gravis. No congenital anomalies were identified in any of the newborns. CONCLUSIONS: The clinical course of myasthenia gravis during pregnancy is variable, with a significant proportion of patients experiencing worsening of the clinical symptoms. However, neonatal transient myasthenia was uncommon in our patient population

Treatment of myasthenia gravis patients with calcineurin inhibitors in Japan: A retrospective analysis of outcomes

Objectives Calcineurin inhibitors (CNI) are approved for the treatment of myasthenia gravis (MG) in Japan. However, the extent to which CNI have been effective remains unclear. Here we report data regarding CNI use and outcomes of MG. Methods We evaluated 640 consecutive MG patients by a multicenter survey. Patients not receiving any immune treatment were excluded, and cross-sectional and retrospective data of 515 patients receiving immune treatment with (n = 312) or without (n = 203) CNI were analyzed. Results Compared with patients treated without CNI, those treated with CNI had a higher frequency of MG Foundation of America Class III-V and higher severity disease at the worst clinical condition, and also had current higher severity, worse quality of life and higher daily doses of prednisolone, despite taking equivalent prednisolone dosages during the course of treatment. Achieving a treatment target was less frequent in the group treated with CNI. Onset age was not different between the two groups. Duration before CNI use after starting corticosteroids was 4.4 ± 6.3 years. Among those treated with CNI, late-onset MG patients achieved a more favorable current condition than did those with early-onset and thymoma-associated MG, whereas there was no such difference without CNI treatment. Conclusions CNI were given to severely ill MG patients with no attempt to select those more likely to respond, and failed to exert a strong impact on MG therapy. CNI should be given aggressively to patients with factors known to enhance susceptibility to these drugs, such as higher age at onset and early-stage disease

Clinical features and treatment status of adult myasthenia gravis in Japan

Objective Myasthenia gravis (MG) is classified as early-onset MG (EOMG; age at onset ?49 years), late-onset MG (LOMG; age at onset ?50 years) or thymoma-associated MG (TAMG) (E-L-T classification). To clarify the characteristics of each group in the E-L-T classification in Japan, we carried out multicenter analyses of MG. Methods A total of 640 adult patients from 11 MG centers participated in the study. Age at onset, sex, clinical symptoms, frequency of crisis, thymic pathology, positivity of autoantibodies against acetylcholine receptor (AChR) and muscle-specific receptor tyrosine kinase (MuSK), selected treatment, Cushingoid appearance and post-intervention status were evaluated in each group. Results EOMG, LOMG and TAMG accounted for 44%, 33%, and 23% of the patients, respectively. Females predominated in the EOMG group (77%), whereas there was no sex difference in the LOMG group. The frequency of ocular MG was the highest in the LOMG group (EOMG 15%, LOMG 38%, TAMG 12%). Bulbar symptoms and crisis were most frequent in the TAMG group. Anti-AChR antibody was always positive in patients with TAMG (EOMG 70%, LOMG 78%, TAMG 99%), whereas anti-MuSK antibody was never positive in TAMG patients, and more frequently detected in EOMG patients than in LOMG patients. Thymectomy was carried out in 51% of EOMG patients, 26% of LOMG patients and 97% of TAMG patients. Immunotherapy was carried out most aggressively in TAMG patients, and least aggressively in LOMG patients. Minimal manifestations or better with prednisolone ?5 mg were achieved only in one-third of EOMG and TAMG patients. Conclusion Thymoma-associated MG required the most aggressive immunotherapy, followed by early-onset MG

A single-blinded trial of methotrexate versus azathioprine as steroid-sparing agents in generalized myasthenia gravis

<p>Abstract</p> <p>Background</p> <p>Long-term immunosuppression is often required in myasthenia gravis (MG). There are no published trials using methotrexate (MTX) in MG. The steroid-sparing efficacy of azathioprine (AZA) has been demonstrated after 18-months of starting therapy. However, AZA is considered expensive in Africa. We evaluated the steroid-sparing efficacy of MTX (17.5 mg weekly) compared with AZA (2.5 mg/kg daily) in subjects recently diagnosed with generalized MG by assessing their average monthly prednisone requirements.</p> <p>Methods</p> <p>The primary outcome was the average daily prednisone requirement by month between the two groups. Prednisone was given at the lowest dose to manage MG symptoms and adjusted as required according to protocol. Single-blinded assessments were performed 3-monthly for 2-years to determine the quantitative MG score and the MG activities of daily living score in order to determine those with minimal manifestations of MG.</p> <p>Results</p> <p>Thirty-one subjects (AZA n = 15; MTX n = 16) satisfied the inclusion criteria but only 24 were randomized. Baseline characteristics were similar. There was no difference between the AZA- and MTX-groups in respect of prednisone dosing (apart from months 10 and 12), in quantitative MG Score improvement, proportions in sustained remission, frequencies of MG relapses, or adverse reactions and/or withdrawals. The MTX-group received lower prednisone doses between month 10 (p = 0.047) and month 12 (p = 0.039). At month 12 the prednisone dose per kilogram bodyweight in the MTX-group (0.15 mg/kg) was half that of the AZA-group (0.31 mg/kg)(p = 0.019).</p> <p>Conclusions</p> <p>This study provides evidence that in patients with generalized MG methotrexate is an effective steroid-sparing agent 10 months after treatment initiation. Our data suggests that in generalized MG methotrexate has similar efficacy and tolerability to azathioprine and may be the drug of choice in financially constrained health systems.</p> <p>Trial registration</p> <p>SANCTR:DOH-27-0411-2436</p