Lambert-Eaton myasthenic syndrome and polyneuropathy in a patient with epidermoid carcinoma of the lung

Autoimmune paraneoplastic syndromes associated to lung cancer: A systematic review of the literature Part 4: Neurological paraneoplastic syndromes, involving the peripheral nervous system and the neuromuscular junction and muscles

The development of new immune treatment in oncology and particularly for lung cancer may induce new complications, particularly activation or reactivation of auto-immune diseases. In this context, a systematic review on the auto-immune paraneoplastic syndromes that can complicate lung cancer appears useful. This article is the fourth of a series of five and deals mainly with neurological paraneoplastic syndromes involving the peripheral nervous system and the neuromuscular junction and muscles.

Distinct evolution of calcium channel antibody types in Lambert-Eaton myasthenic syndrome

To determine whether titers of anti-P/Q type and anti-N type calcium channel antibodies provide distinct information, both types of assay were performed during follow-up of 7 patients with Lambert-Eaton myasthenic syndrome (LEMS). In 4 patients with both antibody responses, titers evolved independently and often in an inverse relationship. Two patients with squamous cell lung carcinoma (SqCLC) produced anti-N type channel antibodies, but no detectable anti-P/Q channel responses. These results suggest that anti-N channel autoantibodies constitute an immune response distinct from the anti-P/Q type channel specificity and can also correlate with clinical evolution. Consequently combined assays may provide more comprehensive information during follow-up of LEMS.

Difficultés autour d’un syndrome de Lambert-Eaton

INTRODUCTION

The diagnosis and treatment of the neurological paraneoplastic syndromes associated with lung cancer can pose a challenge both to general physicians and neurologists as well as pulmonologists.

CASE REPORT

A 53 year-old heavy smoker presented with a Lambert-Eaton myasthenic syndrome (LEMS). Bronchoscopy was normal but radiological examinations revealed a lymph node in site 4R. The pathological diagnosis after mediastinoscopy was negative. Twenty-five months later, an opacity on chest X-ray led to a biopsy which revealed a squamous cell carcinoma. A lobectomy was performed for a pT2N0M0 lesion. A significant improvement of neurological symptoms was seen. The myasthenic syndrome reappeared 21 months later. A local and general relapse was diagnosed. The patient died 10 months later despite chemotherapy.

CONCLUSION

LEMS occurs because of an immunological reaction against voltage-dependent calcium channels. LEMS is generally associated with small cell lung cancer occurring in three percent of cases. However, the case that we report shows the unusual association of LEMS with non small-cell lung cancer and highlights the difficulties associated in the management of this condition.

Remote neurologic manifestations of cancer

Paraneoplastic disorders may affect any part of the central or peripheral nervous systems. Although relatively uncommon, these disorders are a significant cause of neurologic morbidity for cancer patients. At least some paraneoplastic syndromes are believed to be caused by an autoimmune reaction against shared tumor-neural antigens. This article summarizes the clinical features of paraneoplastic disorders, the current evidence for autoimmunity, and guidelines for diagnosis and treatment.

Intrathecal immune response in patients with neuroborreliosis: specificity of antibodies for neuronal proteins

Cerebrospinal fluid (CSF) and serum samples of 47 patients with serologically proven neuroborreliosis were examined by Western blotting for antibodies to a crude extract of human cortex (CNS) comprising a multitude (> 40) of protein bands. Intrathecal synthesis of total immunoglobulins was determined by the Reiber formula and of autoantibodies to CNS proteins by enzyme-linked immunoassay (ELISA) and by Western blotting. Employing ELISA, intrathecal synthesis of autoantibodies (IgG, IgM and/or IgA) was demonstrated in 40 of 47 patients with neuroborreliosis (85%), in 5 of 40 with multiple sclerosis (12%), and in 22 of 40 with viral meningoencephalitis (55%). Of 40, 35 and 15 patients with neuroborreliosis and an intrathecal synthesis of total IgG, IgM or IgA, 20 revealed an intrathecal production of IgG antibodies (50%), 24 of IgM antibodies (68%) and 6 of IgA autoantiodies (40%) in the CSF. The specificity of autoantibodies differed greatly between most patients. Of 24 different CNS proteins which elicited an immune response in various patients, identities could be determined only for the myelin basic protein (5 of 40) and for the three neurofilament proteins (NF-68, NF-150, NF-200) (13 of 40 patients). In this limited number of patients no significant correlation between individual clinical symptoms and certain autoantiodies could be detected. The higher frequency of intrathecally produced autoantibodies in patients with neuroborreliosis is assumed to result from mitogenic rather than specific activation of autoreactive B-cell clones by Borrelia burgdorferi. The pathogenic relevance of these autoantibodies remains to be determined.