RESUMEN
INTRODUCTION: The diagnostic sensitivity of repetitive nerve stimulation (RNS) in patients with myasthenia gravis (MG) varies as a function of the number of muscles or the choice of muscles studied. METHODS: By exploring 12 muscles bilaterally, we evaluated the global sensitivity of RNS at rest, the sensitivity in different clinical forms, and the sensitivity of different combinations of muscles studied. RESULTS: The global sensitivity of RNS was 82%, and specificity was 100%. The sensitivity in the MG subgroups was as follows: ocular (O) = 67%; oculobulbar (OB) = 86%; and generalized (G) = 89%. The most sensitive muscles were the anconeus in group O, orbicularis oculi (OO) or nasalis in group OB, and the trapezius in group G. Maximum sensitivity was obtained by exploring OO, trapezius, and anconeus bilaterally. CONCLUSIONS: We recommend bilateral exploration of at least 3 muscles, a facial muscle, trapezius, and anconeus. Muscle Nerve 55: 532-538, 2017.
Asunto(s)
Estimulación Eléctrica/métodos , Músculo Esquelético/fisiopatología , Miastenia Gravis/diagnóstico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Autoanticuerpos/sangre , Electromiografía , Ácidos Grasos Monoinsaturados/inmunología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Examen Neurológico , Receptores Colinérgicos/inmunología , Estudios Retrospectivos , Sensibilidad y Especificidad , Índice de Severidad de la Enfermedad , Adulto JovenRESUMEN
We retrospectively analyzed three patients with pure motor neuronopathy followed for more than four years in our center. The patients presented a rapidly progressive lower motor neuron syndrome (LMNS) over the course of a few weeks leading to a severe functional impairment. The neurological symptoms preceded the diagnosis of a breast adenocarcinoma and a thymoma in the first two patients, one of them with anti-CV2/CRMP5 antibodies. Cancer was not detected in the third patient who had circulating anti-Hu antibodies. A final diagnosis of paraneoplastic syndrome was made after investigations for alternative causes of lower motor neuron syndrome. Early diagnosis, combined treatment of the underlying cancer, and immunomodulatory treatment led to neurological improvement of the disease in two out of the three cases in which the cancer was diagnosed. Cases of subacute LMNS with rapid progression may occur as an expression of a paraneoplastic neurological syndrome. Identification of these syndromes is important, as the treatment of underlying malignancy along with immunomodulatory treatment may result in a favorable long-term outcome of these potentially fatal diseases.
