Autoantibody Profiles of Myasthenia Gravis, Thymoma & Lambert-Eaton Myasthenic Syndrome

Autoantibodies Aiding the Diagnosis of LES

July 2009

Testing for antibodies with neuronal calcium channel specificity also aids the diagnosis of Lambert-Eaton syndrome. There are 2 types of calcium channel antibodies tested for in the myasthenia gravis/Lambert-Eaton syndrome evaluation. These are of P/Q-type and N-type. P/Q-type calcium channel antibodies are positive in 95% of patients who are non-immunosuppressed and 99% of patients with cancer that have Lambert-Eaton syndrome. This antibody distinguishes Lambert-Eaton syndrome from myasthenia gravis in the appropriate clinical and electrophysiological context that I outlined earlier. Sometimes the P/Q-type calcium channel antibodies are undetectable at symptom onset and should be reevaluated at 12 months, if the disorder is clinically suspected. And, seronegativity for this antibody does not exclude a diagnosis of Lambert-Eaton syndrome.

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Aiding the Diagnosis of LES

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Jump to section:

• Introduction
• Serological Diagnostic Algorithms
• 'Hot Topic' Points
• What are MG and LES?
• What are MG and LES?
• MG: Clinical Diagnosis
• MG: Neoplastic Accompaniments
• LES: Clinical Diagnosis
• LES: Electromyography (EMG) Findings
• LES: Neoplastic Accompaniments
• Autoantibodies Aiding MG Diagnosis
• Autoantibodies Aiding MG Diagnosis
• Single Assay Detects AChR Modulating and AChR Blocking Antibodies
• Serum AChR Modulating Antibody Values and Interpretation
• Reasons to Discontinue Testing for AChR Blocking Antibody
• Striational Antibodies
• Autoantibodies Detected in MG Patients with Thymoma
• Autoantibodies Aiding the Diagnosis of LES
• Autoantibodies Aiding the Diagnosis of LES
• Myasthenia Gravis: Adult Diagnostic Algorithm
• Myasthenia Gravis: Pediatric Diagnostic Algorithm
• Myasthenia Gravis: Thymoma Diagnostic Algorithm
• Myasthenia Gravis/Lambert Eaton Syndrome Diagnostic Algorithm
• Summary
• Questions?