Overview of treatment strategies in paraneoplastic neurological syndromes.

Treatment strategies in paraneoplastic neurological syndromes rely on the three pillars of tumor treatment, immunotherapy, and symptomatic treatment, the first one being by far the most important in the majority of patients and syndromes. Classically, antibodies against extracellular antigens are directly pathogenic, and patients with these syndromes are more responsive to immunomodulatory or immunosuppressive treatments than the ones with antibodies against intracellular targets. This chapter first discusses some general principles of tumor treatment and immunotherapy, followed by a closer look at specific treatment options for different clinical syndromes, focusing on symptomatic treatments.

[Lambert-Eaton Myasthenic Syndrome].

Lambert-Eaton myasthenic syndrome (LEMS), an autoimmune disorder that affects the neuromuscular junction, is characterized by proximal muscle weakness, reduction of tendon reflexes, and autonomic dysfunction. LEMS shows a prevalence of approximately 0.25-0.27 per 100,000 population. The characteristic muscle weakness observed in patients with LEMS is attributed to the role of pathogenic autoantibodies directed against voltage-gated calcium channels (VGCC) present on the presynaptic nerve terminal. Notably, 50-60% of patients with LEMS have an associated tumor, small-cell lung carcinoma (SCLC), which also expresses functional voltage-gated calcium channels (VGCC). The Japanese LEMS diagnostic criteria 2022 recommend documentation of typical electrophysiological abnormalities combined with myasthenic symptoms for accurate diagnosis. P/Q-type VGCC antibody positivity strongly supports the diagnosis. Treatment options are categorized as oncological treatment, immunotherapy, and symptomatic treatments. Effective treatment of the tumor can improve LEMS in patients with SCLC. Most patients benefit from 3,4-diaminopyridine administration for symptomatic treatment. A treatment algorithm is established by the clinical practice guidelines 2022.

[The Japanese Clinical Guidelines 2022 for Myasthenia Gravis and Lambert-Eaton Myasthenic Syndrome: An Overview].

The new Japanese clinical guidelines for myasthenia gravis (MG) and Lambert-Eaton myasthenic syndrome (LEMS) were published in 2022. The Following are the salient features of these guidelines (GLs): (1)These are the first Japanese GLs that include a description of LEMS. (2)Diagnostic criteria for both MG and LEMS are described. (3)A high-dose oral steroid regimen with an escalation and de-escalation schedule is not recommended. (4)Refractory MG is defined. (5)The use of molecular-targeted drugs is included. (6)MG is subcategorized into six clinical subtypes. (7)Treatment algorithms for both MG and LEMS are discussed.

Secreción inadecuada de hormona antiduirética y síndrome miasténico de Lambert-Eaton como presentación del cáncer microcítico de pulmón / Inadequate secretion of anti-diuretic hormone and Lambert-Eaton myasthenic syndrome as presentation of small cell lung cancer

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Síndrome miasteniforme de Lambert-Eaton idiopático: Report of one case / Idiopathic Lambert-Eaton myasthenic syndrome

Lambert-Eaton myasthenic syndrome (LEMS) is an autoinmune idiopathic or paraneoplastic syndrome producing antibodies agaisnt presynaptic voltage calcium channels. The clinical features of patients with LEMS are muscle weakness and autonomic dysfunction. We report a 40 years old man with a four years history of proximal weakness, absent tendon reflexes and dry mouth. The diagnosis was confirmed by characteristic electromyographic findings, showing a low-amplitude muscle response that increased dramatically after activation. Circulating antibodies to voltage-gated calcium channel were present. The search for malignant tumors was negative. The patient was treated with prednisone and azathioprine and after four months, he was able to walk and signs of autonomic dysfunction started to subside.

Síndrome miasténico de Eaton-Lambert: un reto diagnóstico y terapéutico / Eaton-Lambert myasthenic syndrome: a diagnostic and therapeutic challenge

El síndrome miasténico de Eaton-Lambert (SMEL) es un padecimiento raro de naturaleza autoinmunitaria que afecta la porción presináptica de la unión neuromuscular. ocurre habitualmente en hombres mayores de 60 años; en dos terceras partes de los casos se relaciona con un padecimiento neoplásico y en el resto se considera "idiopático". La producción de autoanticuerpos contra las compuertas de calcio dependientes de voltaje produce falla en la liberación de aceltilcolina. Las manifestaciones clínicas más sobresalientes son debilidad, hiporreflexia y trastornos en la función autonómica. El SMEL puede preceder al cáncer hasta por varios años, en especial el de células pequeñas de pulmón. La prueba de estimulación repetitiva a frecuencias altas muestra en los pacientes con SMEL un incremento característico en el potencial muscular, que es muy típico del padecimiento. El tratamiento debe encaminarse en tres puntos: manejo oncológico, manipulación de la neurotransmisión e inmunomoduladores/inmunosupresores.

Tratamiento del síndrome de Lambert-Eaton con 3, 4-diaminopiridina y piridostigmina / No disponible

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Síndrome miasteniforme de Eaton-Lambert. Revisión y presentación de un caso / Lambert-Eaton myasthenic syndrome. Review and a case report

El síndrome miasteniforme de Eaton-Lambert (SMEL) es un trastorno autoimmune presináptico de la transmisión neuromuscular, que se manifiesta clínicamente por debilidad muscular proximal, principalmente de los miembros inferiores, disfunción autosómica y reflejos osteotendinosos disminuidos. Presentamos el caso clínico de un paciente diagnosticado inicialmente de una polineuropatía crónica diabética, que tras la realización de un nuevo estudio electrofisiológico es diagnosticado de SMEL. Se revisan los principales aspectos sobre la enfermedad expuestos en la literatura médica, con particular énfasis en la importancia que tiene un correcto estudio electrofisiológico para el diagnóstico y el papel de la rehabilitación en el tratamiento de estos pacientes

Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune presynaptic disorder of neuromuscular transmission, clinically manifest by proximal muscle weakness, principally involving the lower limbs, autonomic dysfunction and depressed deep tendon reflexes. We present the clinical case of a patient initially diagnosed of chronic diabetic polyneuropathy, who was diagnosed of LEMS after new electrophysiological testing. We review the main aspects on the disease presented in the literature, with special emphasis on the importance of an appropriate electrophysiological study to confirm diagnosis and the role of the rehabilitation in the treatment of these patients