Asymptomatic lambert–eaton syndrome

Authors

  • Eric H. Denys MD,

    Corresponding author
    1. Department of Neurosciences, California Pacific Medical Center, San Francisco, California, USA
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  • Vanda A. Lennon MD, PhD

    1. Department of Laboratory Medicine and Pathology, Mayo Clinic, College of Medicine, Rochester, Minnesota, USA
    2. Department of Neurology, Mayo Clinic, College of Medicine, Rochester, Minnesota, USA
    3. Department of Immunology, Mayo Clinic, College of Medicine, Rochester, Minnesota, USA
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ABSTRACT

Introduction

All descriptions of the Lambert–Eaton syndrome are based on symptomatic patients. We incidentally encountered electromyographic evidence of this syndrome in a patient being studied for another reason. The patient had controlled hypothyroidism and smoked for 9 pack-years but never had symptoms of weakness or had evidence of cancer. Methods: Detailed electrophysiological and serological evaluations were undertaken in this study. Results: Neuromuscular transmission tests were consistent with a presynaptic disorder. Autoantibodies specific for P/Q-type voltage-gated calcium channels (VGCC) were detected in the serum and persisted throughout 7 years of follow-up. Multiple IgG markers of thyrogastric autoimmunity also were detected. Conclusions: This demonstration of asymptomatic Lambert–Eaton syndrome persisting for 8 years provided novel insight into the natural history of the disorder. It is plausible that patients with a subclinical syndrome would have abrupt neuromuscular decompensation when challenged with medications that compromise the safety factor for synaptic transmission. Muscle Nerve 49: 764–767, 2014

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