Timectomía toracoscópica en pacientes con Miastenia Gravis juvenil

Objetivo: Describir la evolución clínica postquirúrgica de una serie de casos de pacientes con Miastenia Gravis juvenil (MGJ) tratados con timectomía por toraoscópica videoasistida (TVA) derecha. Materiales y Métodos: Estudio retrospectivo que incluyó 13 pacientes pediátricos con diagnóstico de MGJ sometidos a timectomía toracoscópica derecha en la Unidad Médica de Alta Especialidad Hospital de Pediatría, Centro Médico Nacional Siglo XXI de México, entre marzo de 2016 y abril de 2022. Los pacientes fueron caracterizados clínicamente y la enfermedad fue clasificada de acuerdo a los criterios de Osserman. La evolución postquirúrgica se evaluó con la clasificación de DeFilippi para determinar la proporción de pacientes con mejoría y la remisión completa. Resultados: Los pacientes incluidos fueron, en su mayoría, mujeres (84,6%) con edad promedio al diagnóstico fue de 11,1 ± 3,1 años. Las cuatro clasificaciones de MG fueron incluidas, con mayor proporción de MG generalizada leve (38,5%), seguida de ocular (23,1%) y generalizada moderada grave (23,1%). La evaluación de la progresión postquirúrgica demostró que a los tres meses de seguimiento 92,3% presentó mejorías, incluyendo la disminución del uso de medicamentos. La remisión total solo se registró en uno de los pacientes. Los pacientes que tuvieron cirugía antes de los 12 meses de evolución de la MGJ presentaron mejores resultados post timectomía por TVA. Conclusión: Se demostró la utilidad de timectomía por TVA en pacientes pediátricos mexicanos con MGJ. Nuestra experiencia agrega evidencia de que los pacientes pediátricos se benefician de la timectomía, mejorando su estado clínico y disminuyendo el uso de medicamentos y complicaciones e la enfermedad.

Objective: To describe the post-surgical clinical evolution of a case series of patients with juvenile myasthenia gravis (JMG) treated with right video-assisted thoracoscopic (TVA) thymectomy. Materials and Methods: Retrospective study that included 13 pediatric patients with JMG who underwent right TVA thymectomy at the Siglo XXI National Medical Center of Mexico between March 2016 and April 2022. Patients were clinically characterized, and the disease was classified according to Osserman's criteria. Post-surgical evolution was evaluated using the DeFilippi classification to determine the proportion of patients with improvement and complete remission. Results: The included patients were mostly women (84.6%) with a mean age at diagnosis of 11.1 ± 3.1 years. The four MG classifications were included, with the highest proportion of mild generalized MG (38.5%), followed by ocular (23.1%) and moderate-severe generalized (23.1%). The evaluation of post-surgical progression showed that after three months of follow-up, 92.3% presented improvements, including a decrease in the use of medications. Complete remission was only recorded in one of the patients. Patients who underwent surgery before 12 months of evolution of JMG had better results after TVA thymectomy. Conclusion: The usefulness of TVA thymectomy in Mexican pediatric patients with JMG was demonstrated. Our experience adds evidence that pediatric patients benefit from thymectomy by improving their clinical status and decreasing the use of medications and complications of the disease.

Enfermedades inmunomediadas del sistema nervioso periférico / Peripheral nervous system immunological disorder

Las enfermedades autoinmunes del sistema nervioso periférico son frecuentes en pediatría. Las más importantes son el síndrome de Guillain-Barré, la miastenia gravis juvenil y la dermatomiositis juvenil. Tienen en común ser causadas por acción de anticuerpos específicos que producen la signología clínica, reacción que puede ser gatillada por un cuadro viral o bacteriano, como ocurre principalmente en SGB. La polineuropatía aguda inflamatoria desmielinizante es más frecuente. Existe también la forma axonal motora. Ambas tienen clínica progresiva ascendente. El tratamiento específico es la inmunoglobulina 2 g/ kg. La miastenia gravis juvenil se expresa por signos oculares, generalizados y fatigabilidad fluctuante. Puede comprometer la función respiratoria desencadenando crisis miasténica. Se trata con anticolinesterásicos, corticoides, inmunoglobulinas e inmunosupresores. La timectomía ha mostrado recientemente su efectividad. La dermatomiositis juvenil se expresa por signos cutáneos y musculares. Se diagnostica por elevación de enzimas musculares, biopsia y resonancia musculares y se trata con corticoides, inmunoglobulinas e inmunosupresores. Tanto el síndrome de Guiilain-Barré, como la miastenia gravis y la dermatomiositis juvenil, tienen buen pronóstico.

Autoimmune diseases of the peripheral nervous system are common in pediatrics. Guillain-Barré syndrome, juvenile myasthenia gravis, and juvenile dermatomyositis are the most important. Their common pathogenesis involves the action of specific autoantibodies which are frequently triggered by viral or bacterial infection. Acute inflammatory demyelinating polyneuropathy is the most frequent pathological feature. There is also a motor axonal form. Both have a progressive ascending clinical course. The specific treatment is immunoglobulin 2 g/kg. Juvenile myasthenia gravis is expressed by ocular signs and generalized and fluctuating fatigability. It can involve respiratory functions triggering a myasthenic crisis. It is treated with anticholinesterase agents, corticosteroids, immunoglobulins, and immunosuppressants. Thymectomy has recently shown effectiveness. Juvenile dermatomyositis is expressed by skin and muscle signs. Elevated muscle enzymes, muscle biopsy, and magnetic resonance imaging contribute to the diagnosis. It is treated with corticosteroids, immunoglobulins, and immunosuppressants. All three disorders, Guillain-Barré, juvenile myasthenia gravis, and juvenile dermatomyositis have a good prognosis.

Thymectomy in Children with Juvenile Myasthenia Gravis: Is It Recommended?.

Objective: Juvenile myasthenia gravis (JMG) is a rare disease with possible severe forms. Thymectomy is supported by many authors particularly in generalised forms with positive AcetylCholine Receptor Antibody (AChR- Ab). The aim of our study was to discuss the indication and the outcome of thymectomy in five children with JMG. Methods: We performed a retrospective study of the medical files of patients with JMG, who were hospitalised in our pediatric surgery department for thymectomy. For all the children we performed Acetylcholine Receptor Autoantibody (ACHRAB) test-system producer, a chest x-ray, a chest Computed Tomography Scan (CT-scan) and a Magnetic Resonance Imaging (MRI). Thymectomy was indicated on the presence of anomalies on CT-Scan or MRI and realised via either thoracotomy or video-assisted thoracoscopy. The study was conducted with the approval of the ethics committee at our institution. Results: Based on our findings, thymectomy in JMG with imaging anomalies seems to be associated with clinical improvement. In our patients complete remission after surgery was seen in one case, a clinical improvement with a decrease of the medical therapeutic dosage was noted in three other cases. One patient could not be evaluated because of non adherence to medical treatment. Surgery by thoracotomy or video assisted thoracoscopy (VAT) was also well tolerated by all the patients. Conclusion: The benefits of thymectomy in children with JMG are still controversial. However, many researchers have reported a sustained improvement of symptoms in the majority of patients after thymectomy. Our findings seem to encourage thymectomy in cases of JMG and particularly when imaging anomalies are found. VAT thymectomy was well tolerated and it is considered by many researchers to be the standard method for thymectomy in children.