Paraneoplastic Lambert-Eaton Myasthenic Syndrome With Limbic Encephalitis: Clinical Correlation With the Coexistence of Anti-VGCC and Anti-GABAB Receptor Antibodies.

OBJECTIVE: To characterize Lambert-Eaton myasthenic syndrome and limbic encephalitis with coexistent voltage-gated calcium channel (VGCC) antibody and γ-aminobutyric acid (GABA) B receptor antibody.

METHODS: Case study.

RESULTS: A 57-year-old man presented with 6 months of weakness, unsteadiness, and vision difficulties. Examination revealed proximal weakness and diminished reflexes. Electrodiagnostic study revealed low-amplitude motor potentials and facilitation on high-frequency stimulation. Laboratory evaluation identified P/Q-type VGCC antibody. Positron emission tomography identified a mediastinal lesion, confirmed as small-cell lung carcinoma. The patient developed confusion and seizures. Cerebrospinal fluid analysis identified antibodies to GABAB receptor.

CONCLUSIONS: This case describes a patient with Lambert-Eaton myasthenic syndrome, limbic encephalitis, and autoantibodies to VGCC and GABAB receptor. Atypical presentation of paraneoplastic neurological syndromes could indicate the presence of a second antibody that may have significant impact on therapy.