Myasthenia gravis and thymoma: evaluation of 41 patients

Abstract

-We evaluated the epidemiological, clinical, laboratory and therapeutical aspects of 41 patients with thymomatous myasthenia gravis. Thirty five patients (85.36%) were submitted to thymectomy. Follow-up ranged from two to 18 years. Diagnosis of thymoma was based upon clinical investigations and CT scan of the anterior mediastinum and in 11 patients supported by immunological tests of anti-striated muscle antibodies with a positive result in more than 80% of cases. Histopathologic examination of all thymomectomized patients confirmed the diagnosis of thymoma. There was a significant predominance of benign over malignant thymoma. Occurred higher prevalence of male patients and of patients over 40 years of age. The therapeutical strategy to control myasthenic clinical findings was the same as that for non-thymomatous myasthenia gravis. The corticosteroids associated to cytotoxic drugs were less often used. Radiotherapy of the anterior mediastinum was more often used in patients having invasive tumors submitted to surgery or not. With regard to survival and control of myasthenia gravis, especially in younger patients and in those submitted to early surgery, results of treatment were surprisingly favorable.KEY WORDS: myasthenia gravis, thymoma, thymectomy.Miastenia grave e timoma: avaliação de 41 pacientes RESUMO -Avaliamos 41 pacientes com miastenia grave timomatosa sob os aspectos epidemiológico, clínico e terapêutico. Trinta e cinco pacientes (85,36%) foram timectomizados. O seguimento clínico variou de dois meses até 18 anos. O diagnóstico do timoma foi fundamentado no estudo de imagem do mediastino (tomografia axial computadorizada) e, em 11 pacientes, complementado com a determinação sérica de anticorpos para músculo estriado com resultado positivo em mais de 80% dos casos e confirmado pelo exame anátomo-patológico do timo realizado em todos os pacientes operados. Ocorreu predomínio significante de timomas benignos sobre timomas malignos, forma clínica generalizada severa, frequente envolvimento do sexo masculino e, em pacientes com mais de 40 anos de idade. A estratégia terapêutica para o controle dos sintomas miastênicos foi a mesma que para os pacientes não timomatosos. O emprego de imunossupressão medicamentosa esteróide associada a drogas citotóxicas foi menos frequente. A radioterapia foi usada com mais frequência nos pacientes portadores de tumores invasivos operados ou não. PALAVRAS-CHAVE: miastenia grave, timoma, timectomia.Acquired myasthenia gravis (MG) is an immunological disease with antibody activity against the acetylcholine nicotine receptor (antiAChR) of the neuromuscular junction, with fluctuant weakness of the skeletal muscle which improves with the administration of cholinergic drugs (CD). These antibodies are produced by B lymphocytes activated by helper T lymphocytes antigen-specific (CD4) 1,2 in the thymus and peripheral blood of patients with MG 3,4 .

Clinical profile of patients with myasthenia gravis followed at the University Hospital, Federal University of Minas Gerais

“…[17][18][19][20][21][22][23][24][25][26][27][28][29][30] Ocular symptoms were the first symptoms described by most MG patients; however, they were not considered the main problem with the disease progression. Bulbar symptoms were considered the most disabling, which is in agreement with some studies.…”

“…In contrast, even recent Brazilian case series 18,19,22,23,25,27,29 used the clinical classification of Osserman-Gerkins, while the recommended standards of clinical research on MG and the international literature have adopted MGFA since the early 2000s. 21,30 conclusion Despite the clinical heterogeneity of MG, the clinical and demographic profiles and therapeutic strategies reported in Brazilian case series are quite similar.…”

“…[9][10][11][12][13][14][15][16] These heterogeneous results may be partly explained by methodological differences and biological factors. [17][18][19][20][21][22][23] There is, for instance, hormonal and/ or environmental influence on disease development.…”

“…Conversely, a few Brazilian case series have been reported, describing clinical and sociodemographic features of patients followed at specialized clinics. [17][18][19][20][21][22][23][24][25][26][27][28][29][30] The aim of the current study was to determine the clinical profile of patients with MG under treatment at the Neuromuscular Diseases Clinic of the University Hospital, Federal University of Minas Gerais (UFMG), com-paring it with other series to draw a picture of the MG in Brazil.…”

Myasthenia gravis in Ceará, Brazil: clinical and epidemiological aspects

“…In Brazil, there are relatively limited data on the occurrence of MG and its clinical and epidemiological aspects (Table 1) 5, 14,16 . There have been no reported studies of MG in Northeast Brazil.…”