Pathophysiology
- Cancerous plasma cells secrete cytokines that signal osteoclasts to dismantle bone, creating lytic ("punched-out") lesions in spine, pelvis, ribs, and skull
- Produce massive amounts of nonfunctioning M-proteins — M-Spike on protein electrophoresis is the hallmark diagnostic finding
- Bence Jones proteins (M-protein fragments) pass into kidneys and are directly toxic to renal tubules, potentially causing kidney failure
- Interferes with normal blood cell production: anemia, thrombocytopenia, reduced infection resistance
- Hypercalcemia: Excessive calcium released from dismantled bone causes confusion, nausea, and further kidney damage
- Almost exclusively affects those over 50. Twice as common among African Americans
Signs and Symptoms
Hallmark Indicators
- Deep bone pain, particularly back, ribs, or hips
- Spontaneous fractures with little or no trauma (pathologic fractures)
- Anemia: profound fatigue, weakness, pallor
- Decreased urine output or signs of kidney failure
- Recurrent bacterial infections
- Lower extremity weakness
Red Flags and Rule-Outs
- Spontaneous fractures with minimal trauma: Extreme bone fragility — contraindicated for any forceful technique
- Deep bone tenderness on palpation of sternum, spine, or ribs: Reflects marrow expansion and subperiosteal infiltration
- Decreased urine output or confusion: May indicate hypercalcemia or renal failure — urgent medical concern
- Bence Jones proteins in urine: Definitive indicator of myeloma-related renal risk
- Multiple lytic ("punched-out") lesions on imaging: Characteristic of myeloma
MT Considerations
- Fracture risk is the primary safety concern: Extreme bone fragility requires highly conservative pressure and positioning. Avoid deep pressure, joint traction, and high-velocity movements
- Platelet precaution: If platelets are low, use extremely light pressure comparable to applying lotion
- Local contraindications: No intrusive techniques or deep pressure over known tumor sites or bone lesions
- Positioning: Prone may cause pain due to fragile ribs and vertebrae. Use bolstering alternatives
- Clinical integration: Coordinate with medical team to monitor kidney stability and treatment complications
- Amyloidosis link: Myeloma is a common precursor to secondary amyloidosis (inflammatory proteins accumulating in heart or lungs)
- Treatment side effects: See chemotherapy and radiation-therapy
CMTO Exam Relevance
- Lytic ("punched-out") lesions on bone imaging are characteristic of myeloma
- Bence Jones proteins in urine indicate myeloma-related renal risk
- M-Spike on protein electrophoresis is the hallmark diagnostic finding
- Hypercalcemia from bone destruction causes confusion, nausea, and kidney damage
- Myeloma is a common precursor to secondary amyloidosis
- Almost exclusively affects those over 50. Twice as common among African Americans
Key Takeaways
- Multiple myeloma actively dismantles bone via osteoclast signaling, creating extreme fracture risk at multiple sites simultaneously
- Bence Jones proteins are directly toxic to renal tubules — the hallmark of myeloma-related kidney damage
- Pressure must be extremely conservative. Avoid deep techniques, joint traction, and forceful movements over fragile bone
- Hypercalcemia from bone destruction is a dangerous systemic complication
- Coordinate with the healthcare team to monitor kidney stability and treatment complications