SESSION TITLE: Infectious Disease Cases II
SESSION TYPE: Affiliate Case Report Slide
PRESENTED ON: Sunday, October 27, 2013 at 01:15 PM - 02:45 PM
INTRODUCTION: Lambert-Eaton myasthenic syndrome (LEMS) is a neuromuscular autoimmune disease which is associated with autoantibodies directed against voltage-gated calcium channels (VGCC) that are located on presynaptic nerve terminal. Clinical manifestations of this syndrome include proximal muscle weakness, autonomic dysfunction, and reduced deep tendon reflexes. Approximately 50% of patients with LEMS have small cell lung cancer (SCLC). There is a weaker association with other diseases such as non-small cell lung cancer, thymoma, prostate cancer, and lymphoproliferative disorders. We describe a case of tuberculosis presenting with LEMS which has not been reported previously per our literature review.
CASE PRESENTATION: 74 year old male with history of diabetes, chronic kidney disease, and atrial fibrillation developed proximal muscle weakness of thighs and arms. Electromyogram (EMG) findings and presence of VGCC antibodies were consistent with LEMS. Patient had a positron emission tomography - computed tomography (PET-CT) to evaluate for small cell lung cancer and was found to have a moderate left pleural effusion with fluorodeoxyglucose (FDG) uptake. Diagnostic thoracentesis revealed exudative fluid with lymphocyte predominance. Cytology testing was negative for malignancy. Bacterial, fungal cultures as well as acid-fast bacillus (AFB) smear were negative. Thoracentesis was repeated with similar results. Five weeks after 2nd thoracentesis, the AFB culture grew Mycobacterium tuberculosis (TB). Patient’s risk factors for TB included travel to East Asia in remote past. He was started on 4 drug regimen with Rifampin, Isoniazid, Pyrazinamide, and Ethambutol. Based on drug sensitivities, his medications were narrowed to Isoniazid and Rifampin. He finished a 6 month course of treatment and his muscle strength significantly improved. He had another PET-CT after finishing therapy which showed complete resolution of left pleural effusion and no abnormal FDG uptake.
DISCUSSION: We report an atypical case of pulmonary tuberculosis presenting with LEMS and a pleural effusion. LEMS frequently occurs as part of a paraneoplastic syndrome most commonly associated with SCLC. There is one prior case report of recurrent Escherichia coli pneumonia in a patient with LEMS. However, an association between this syndrome and TB has not been documented previously. Furthermore, tuberculosis infection has not been described to be associated with an autoimmune disease except in context of patients with latent TB who are started on immunosuppressive medications.
CONCLUSIONS: Pulmonary tuberculosis may be associated with Lambert-Eaton myasthenic syndrome.
Reference #1: Titulaer MJ, Lang B, Verschuuren JJ. Lambert-Eaton Myasthenic Syndrome: From Clinical Characteristics to Therapeutic Strategies. Lancet Neurology 2011; 10:1098-107.
Reference #2: Wathen CG, Capewell SJ, Heath JP, et al. Eaton-Lambert Syndrome Associated with idiopathic Recurrent Lobar Pneumonia. Thorax 1988 43: 574-575.
DISCLOSURE: The following authors have nothing to disclose: Dmitriy Kogan, Michael Sirdofsky, Eric Anderson
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