From the Guidelines
The workup for generalized weakness in a patient with bony metastatic multiple myeloma should begin with a comprehensive assessment focusing on both myeloma-related and non-myeloma causes, including laboratory tests and imaging studies, as recommended by the NCCN Guidelines for MM 1.
Initial Assessment
Start with laboratory tests including:
- Complete blood count to assess for anemia (common in myeloma)
- Comprehensive metabolic panel to check calcium levels (hypercalcemia), renal function (myeloma kidney)
- Serum protein electrophoresis to evaluate disease status
- Measure vitamin D, B12, and thyroid function as deficiencies can contribute to weakness
Further Evaluation
Assess for:
- Hyperviscosity syndrome with serum viscosity if the patient has high paraprotein levels
- Spinal cord compression with urgent MRI if there are neurological symptoms, as this is a medical emergency requiring immediate dexamethasone and radiation oncology consultation
- Peripheral neuropathy with electromyography and nerve conduction studies if suspected, which may be disease-related or treatment-induced (particularly from proteasome inhibitors like bortezomib)
Additional Considerations
- Assess medication side effects, especially from steroids (proximal myopathy), chemotherapy, and pain medications
- Evaluate for infection, as patients are immunocompromised
- Consider cardiac involvement with BNP and echocardiogram if amyloidosis is suspected
- Nutritional assessment and physical therapy consultation are important for comprehensive management
Treatment Approach
Treatment should address the underlying cause while continuing appropriate myeloma therapy in consultation with hematology-oncology, and may include bisphosphonates or denosumab for bone-targeting treatment, as recommended by the NCCN Guidelines for MM 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Diagnostic Approach
- The diagnostic workup for a patient with suspected multiple myeloma, including those with generalized weakness and bony metastatic myeloma, should include:
- Complete blood count with differential
- Serum chemistries
- Creatinine, lactate dehydrogenase, and beta2-microglobulin tests
- Immunoglobulin studies
- Skeletal survey
- Bone marrow evaluation 2
- Renal function should be assessed using the estimated glomerular filtration rate (eGFR) and serum creatinine levels 3
- Urinary proteins, such as transferrin, IgG, albumin, and low-molecular-weight proteins, can be useful in diagnosing renal impairment at an early stage 4
Initial Management
- For geriatric patients presenting with generalized weakness, a minimum of laboratory and imaging testing is recommended, with the addition of neuroimaging if focal weakness is discovered 5
- A wide differential diagnosis should be considered, with attention to geriatric-specific concerns 5
- Patients with multiple myeloma may require thromboprophylaxis, bisphosphonate therapy, and prophylaxis against infection at some point in their treatment 2
- Referral to an oncologist is necessary for initiation of chemotherapy and assessment of eligibility for autologous stem cell transplantation 2