Non-paraneoplastic Lambert-Eaton myasthenic syndrome: a brief review of 10 cases

Abstract

Lambert-Eaton myasthenic syndrome (LEMS) is an immune-mediated disorder of the presynaptic neuromuscular transmission, which more frequently occurs as the remote effect of a neoplasm, in the paraneoplastic form (P-LEMS), or in a non-paraneoplastic form (NP-LEMS); but few studies describe the clinical features of NP-LEMS. We analyzed the clinical manifestations, laboratory findings, electrophysiological studies, and treatment responses in ten Brazilian patients suffering from NP-LEMS. The mean age was 41.5 years. More often neurological findings were hyporeflexia or areflexia with a post-exercise improvement. Treatment response occurred with pyridostigmine, guanidine, prednisone, azathioprine, and cyclosporine; but not response was observed after intravenous immunoglobulin and plasma exchange. Age at onset, clinical manifestations, and electrophysiological abnormalities can help more in the diagnosis than serum antibodies; the symptomatic treatment with pyridostigmine was effective; and the immunosuppressive treatment with prednisone, azathioprine, or cyclosporine was more beneficial than plasma exchange or intravenous immunoglobulin treatment. Key words: Lambert-Eaton myasthenic syndrome, myasthenic syndrome, P/Q-type voltagegated calcium channel antibody, repetitive nerve stimulation, electrophysiological study, treatment.Síndrome miastênica de Lambert-Eaton não paraneoplásica: uma breve revisão de dez casos RESUMO A síndrome miastênica de Lambert-Eaton (LEMS) é uma desordem imunomediada da transmissão neuromuscular pré-sinaptica, que mais frequentemente ocorre como efeito à distância de uma neoplasia, na forma paraneoplásica (P-LEMS), ou na forma não paraneoplásica (NP-LEMS); porém poucos estudos têm descrito as características da NP-LEMS. Nós analisamos as manifestações clínicas, laboratoriais, eletrofisiológicas, e resposta ao tratamento em dez pacientes brasileiros com NP-LEMS. A idade média foi de 41,5 anos. A manifestação neurológica mais freqüente foi hiporeflexia ou arreflexia com melhora após o exercício. A resposta ao tratamento ocorreu com piridostigmina, guanidina, prednisona, azatioprina, e ciclosporina; mas não com imunoglobulina intravenosa e plasmaférese. A idade de início, manifestações clínicas e eletrofisiológicas ajudaram mais no diagnóstico do que os anticorpos séricos; o tratamento sintomático com piridostigmina foi efetivo; e o tratamento imunossupressor com prednisona, azatioprina, ou ciclosporina beneficiou mais do que a plasmaférese ou a imunoglobulina intravenosa. Palavras-chave: síndrome miastênica de Lambert-Eaton, síndrome miastênica, anticorpo anti-canal de cálcio voltagem dependente, estimulação nervosa repetitiva, estudo eletrofisiológico, tratamento.

Five years experience on 3,4-diaminopyridine phosphate in Lambert–Eaton syndrome

“…[ 18 , 19 ] The disorder can be either paraneoplastic (P-LEMS) [ 20 ] or associated with autoimmune disorders (nonparaneoplastic Lambert–Eaton myasthenic syndrome [NP-LEMS]). [ 21 , 22 ] Antibodies to P/Q-type VGCCs can be detected in over 90% of both NP- and P-LEMS, since they are specific for the disorder. [ 23 ]…”

Lambert-Eaton myasthenic syndrome and solitary cerebellar metastasis in a patient with occult small-cell lung cancer: a rare experience

“…There are two types of LEMS-LEMS associated with carcinoma and LEMS without carcinoma. Patients with either type have disease on autoimmune basis 9. VGCC are blocked in patients with LEMS.…”

Lambert-Eaton Myasthenic Syndrome; Pathogenesis, Diagnosis, and Therapy

“…The no-SCLC LEMS group is dominating regarding prevalence as this group has a near normal survival rate. No-SCLC LEMS patients have a lower age of debut than SCLC LEMS [3, 4]. LEMS with SCLC shows a male preponderance, reflecting smoking habits.…”

“…This weakness starts nearly always in proximal muscle groups, especially in the legs. 80% of LEMS patients experience proximal weakness in both arms and legs [4, 7, 8]. Also facial weakness, eye muscle complaints, bulbar muscular weakness, and distal pareses are relatively common.…”