Lambert-Eaton Myasthenic Syndrome Unmasked by Administration of Aggravating Medications

Abstract

We present a case of an elderly female patient presenting with symptoms strongly suggestive of Myasthenia Gravis (MG), but later serological workup was shown to be more consistent with Lambert Eaton Myasthenic Syndrome (LEMS). On presentation, the patient had both profound ptosis and generalized weakness of the upper and lower extremities that were suspected clinically to be due to MG. The case was further complicated by the administration of several medications, which were believed to have unmasked her disease. Diagnostic imaging to assess for thymoma and lung cancer was negative. Screening with the ice-pack test was positive; however, serology for MG was negative. This case illustrates the importance of keeping the differential of LEMS in view in every suspected MG case, even if there is a low suspicion of LEMS initially. In addition, it demonstrates the possibility that the "ice-pack test" can also be positive in LEMS, and MG-unmasking medications may also unmask LEMS, an association that has not been described in our literature review.