From the Research
Imaging studies are not the primary diagnostic tools for Eaton-Lambert syndrome, but chest imaging, specifically CT scans or PET-CT of the thorax, is recommended to screen for underlying small cell lung cancer. The diagnosis of Eaton-Lambert syndrome (Lambert-Eaton myasthenic syndrome or LEMS) relies on electrophysiological studies, particularly repetitive nerve stimulation testing and single-fiber electromyography, which demonstrate the characteristic incremental response to repetitive stimulation 1. Blood tests for voltage-gated calcium channel antibodies are also essential for diagnosis. However, given the association of LEMS with small cell lung cancer, as noted in studies such as 2 and 3, chest imaging is crucial for screening purposes. These imaging studies should be performed at diagnosis and may need to be repeated periodically (every 3-6 months for 2 years) in patients with initially negative scans, particularly in those with risk factors for lung cancer such as smoking history. MRI of the brain and spine is not routinely indicated unless there are symptoms suggesting additional neurological disorders. The use of imaging in LEMS is more about screening for associated conditions like small cell lung cancer rather than diagnosing the syndrome itself, as highlighted by the studies 4, 5, and others which focus more on the treatment and diagnosis through electrophysiological means. Given the most recent and highest quality evidence, the approach to imaging in Eaton-Lambert syndrome prioritizes the detection of small cell lung cancer due to its significant association with LEMS.