Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

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Multiple Myeloma

Basics
Description
  • The most common of the plasma cell dyscrasias (usually with a monoclonal gammopathy) affecting the hematopoietic, musculoskeletal, and renal systems.
  • Classification (plasma cell dyscrasias):
    • Solitary myeloma
    • Multiple myeloma
    • Osteosclerotic myeloma
  • Synonyms: Myeloma; Plasmacytoma
Epidemiology
  • Rare in patients <40 years old
  • The Male:Female ratio is ~2:1.
  • The peak age is the 6th decade of life.
Incidence
~15,000 new cases (United States) annually
 
Risk Factors
Age >40 years
 
Etiology
The cause is unknown.
 
Diagnosis
Signs and Symptoms
  • Bone pain (usually of 6 months’ duration) is the most frequent complaint at diagnosis.
  • Constitutional symptoms of weakness, lethargy, and weight loss often occur.
  • Back pain and rib pain are the 2 most frequent initial skeletal symptoms at presentation.
  • Pathologic fracture usually results in sudden-onset pain.
  • Peripheral neuropathy may be present.
  • Tendency toward bleeding and fever
  • Hypercalcemia is common.
  • Monoclonal gammopathy is revealed by serum electrophoresis and urine immunoelectrophoresis.
Physical Exam
  • Local pain and tenderness may be present.
  • A palpable mass may be found, secondary to extraosseous extension of the tumor or hemorrhage related to it.
  • Peripheral neuropathy may be detected in some patients with osteosclerotic myeloma.
Tests
Lab
  • Hypercalcemia is seen in 1/3 of cases.
  • Serum creatinine levels are elevated in ~50% of patients.
  • Anemia with hemoglobin is <12 mg/dL in 2/3 of patients.
  • Elevated ESRs are >50 mm/hour in 2/3 of patients.
  • Serum electrophoresis and immunoelectrophoresis usually reveal monoclonal gammopathy.
  • Bence Jones proteinuria is noted.
  • Hypergammaglobulinemia may manifest itself as rouleaux formation appreciable on a peripheral blood smear.
Imaging
  • Radiography:
    • Plain film radiographs reveal multiple small, discrete, lytic lesions most commonly involving the axial skeleton (skull, spine, ribs).
    • The surrounding bone does not show a sclerotic reaction, nor is there a periosteal reaction.
  • Because bone scans have a high incidence of false-negative results, they are not used routinely.
    • A skeletal survey to evaluate for distant involvement often is a better study.
Pathological Findings
Monoclonal plasma cells are found in bone marrow.
 
Differential Diagnosis
  • Metastatic bone disease
  • Malignant lymphoma
  • Fibrosarcoma
Treatment
General Measures
  • The mainstay of treatment is chemotherapy.
  • Surgical stabilization with irradiation is used for impending or complete pathologic fractures.
  • External-beam irradiation is used for painful lesions that do not meet the criteria for pathologic fracture.
  • Medical treatment:
    • Orthopaedic surgery consultation to consider surgical stabilization
    • Selected patients are treated with bone marrow transplantation.
      • Diphosphonate therapy has become an integral component of medical therapy because these drugs effectively halt osteoclastic bone resorption.
  • Bone marrow transplantation commonly is offered.
Activity
Limited activity, according to the level of symptoms and the nature of the bony lesions
 
Medication
  • NSAIDs or narcotic analgesics for pain control
  • Chemotherapeutics (prednisone, alkylating agents)
Surgery
  • Mostly internal fixation for stabilization of the long bones
  • Decompression with spinal instrumentation may be necessary for patients with pathologic fractures and neurologic deficits.
Follow-up
Prognosis
  • Prognosis is related to the stage of the disease, with an overall median survival of 18-24 months.
    • Virtually all patients eventually die of the disease.
  • Bone marrow transplantation currently is being tried in an attempt to cure selected patients.
Complications
  • Pathologic fractures
  • Spinal stenosis with compressive myelopathy
  • Renal failure
  • Amyloidosis (CTS)
Patient Monitoring
  • Monitor closely for impending pathologic fractures so that appropriate surgical intervention can occur before completion of pathologic fractures.
  • Patients undergoing chemotherapy are monitored for changes in their serum protein levels to assess the response to treatment.
Miscellaneous
Codes
ICD9-CM
  • 238.6 Solitary myeloma
  • 302.0 Multiple myeloma
FAQ
Q: What is multiple myeloma?
A: Multiple myeloma is a malignant proliferation of plasma cells with end organ damage to bone and the kidneys.
 
Q: Do all patients with multiple myeloma need diphosphonate therapy?
A: Yes, the diphosphonates are very effective in halting the osteoclastic bone resorption. The number of fractures of the long bones and vertebra are decreased markedly.
 
Q: When is surgery necessary in patients with multiple myeloma?
A: Patients with impending fractures or those with severe weightbearing pain benefit from prophylactic fixation. Patients with a complete fracture are treated with internal fixation or a prosthetic arthroplasty.

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