From the Guidelines
A paraneoplastic panel for muscle weakness should be considered when there is suspicion of a paraneoplastic syndrome causing neuromuscular symptoms, and it is recommended to include paraneoplastic autoantibody testing for myositis and neurologic conditions, such as myasthenia gravis, as part of the diagnostic work-up. When evaluating a patient with muscle weakness, it is essential to consider a comprehensive diagnostic approach, including a complete rheumatologic and neurologic history, physical examination, and laboratory tests to evaluate muscle inflammation, such as CK, transaminases, lactate dehydrogenase, and aldolase, as recommended by the American Society of Clinical Oncology clinical practice guideline 1. The paraneoplastic panel should be accompanied by a thorough clinical evaluation, electromyography, and imaging studies to search for an underlying malignancy, as these antibodies often indicate the presence of cancer that may not yet be symptomatic. Some key points to consider when ordering a paraneoplastic panel for muscle weakness include:
- The panel typically includes antibodies associated with muscle weakness, such as anti-Hu, anti-Yo, anti-Ri, anti-amphiphysin, and anti-CV2/CRMP5
- For specific muscle weakness, include anti-Jo-1 and other myositis-specific antibodies
- Blood samples should be collected before immunotherapy is initiated for the most accurate results
- The specific antibodies detected can guide the search for particular cancer types, as certain antibodies are associated with specific malignancies, as noted in the guideline 1. Early detection through this panel can lead to prompt treatment of both the underlying malignancy and the paraneoplastic syndrome, potentially improving neurological outcomes and reducing morbidity and mortality.
From the Research
Paraneoplastic Panel for Muscle Weakness
- Muscle weakness can be a symptom of paraneoplastic syndromes, which are disorders caused by the immune system's response to cancer 2, 3.
- The Lambert-Eaton myasthenic syndrome (LEMS) is a well-known paraneoplastic disorder that affects the neuromuscular junction and can cause muscle weakness 2.
- Paraneoplastic syndromes can be associated with various types of cancer, including small cell lung cancer, breast cancer, and hematologic malignancies 3, 4.
- Anti-Hu and anti-Yo antibodies are commonly found in patients with paraneoplastic neurological syndromes, and their presence can help diagnose these conditions 4, 5.
- Treatment of paraneoplastic syndromes typically involves addressing the underlying cancer, as well as immunosuppressive therapy to reduce the immune system's attack on the nervous system 3, 6.
- A combination of immunoglobulins, cyclophosphamide, and methylprednisolone has been used to treat paraneoplastic neurological syndromes with antineuronal antibodies, but the effectiveness of this treatment is still being evaluated 6.