From the Guidelines
Muscle denervation is not a primary or direct manifestation of multiple myeloma, but rather can occur as a secondary complication due to peripheral neuropathy or other neurological effects associated with the disease or its treatment. Multiple myeloma is a cancer of plasma cells that primarily affects bone marrow, leading to bone lesions, anemia, hypercalcemia, and renal dysfunction. However, neurological complications can occur in multiple myeloma patients through several mechanisms, including spinal cord compression from vertebral fractures or plasmacytomas, peripheral neuropathy from the disease itself or as a side effect of treatments like bortezomib (Velcade) or thalidomide, and amyloidosis which can cause nerve damage 1.
Key Considerations
- Peripheral neuropathy is a significant complication of multiple myeloma, affecting up to 20% of patients at diagnosis, and can be caused by the disease itself or by certain therapies, including thalidomide- and bortezomib-based therapies 1.
- If muscle denervation is observed in a multiple myeloma patient, it's more likely due to one of these secondary complications rather than being a primary feature of the disease.
- Clinicians should investigate for possible spinal cord compression requiring urgent intervention, or medication-induced neuropathy that might necessitate dose adjustment or alternative treatments.
Pathophysiology and Clinical Implications
The pathophysiology involves either direct compression of nerves or toxic effects on peripheral nerves rather than a direct attack on muscle innervation by the malignant plasma cells. This understanding is crucial for the management of multiple myeloma patients, as it guides the clinician towards the appropriate diagnostic and therapeutic approaches to address neurological complications, including muscle denervation, and improve patient outcomes in terms of morbidity, mortality, and quality of life.