Multiple myeloma

Background

• Malignant proliferation of plasma cells overproduction of abnormal antibodies (paraproteins or light-chain protein)
• Symptoms result from accumulation of plasma cells and paraproteins

Clinical Features

• Bone (plasma cell proliferation in marrow)
  • Pathologic fractures
    • Due to lytic lesions and osteopenia
    • ”Punched-out” lytic lesion on x-ray
    • Frequently involve spine, as well as ribs, skull, extremities
  • Bone pain (even in absence of fracture)
    • Commonly in back, ribs, extremities, often worse with movement
• Renal
  • Ranges from mild Cr elevation to ESRD
  • Due to light-chain deposition, myeloma cast nephropathy and/or amyloidosis
  • Hypercalcemia exacerbates
  • Vulnerable to further damage from nephrotoxic mediations/contrast
• Hematologic
  • Anemia
  • Due to plasma cell infiltration in marrow +/- renal failure
  • Hyperviscosity syndrome
    • Increase serum viscosity due to paraproteins poor capillary flow and organ congestion
• Neuro
  • Cord compression due to vertebral fracture or collapse or plasmacytoma
  • Intracranial plasmacytoma (rare)
  • Peripheral neuropathy, radiculopathy
• Hypercalcemia
  • due to local osteolysis
• Infection
  • Impaired plasma cell function decreased effective antibody production
  • Often on immunosuppressive chemotherapy or bone marrow transplant meds
  • splinting due to rib pain/fractures increased pneumonia risk

Evaluation

‘’Definitive diagnosis is by biopsy of marrow or plasmacytoma’’

• CBC
• BMP, ionized Ca, Mg, phos
  • Paraproteins bind calcium, so non-ionized Ca levels could be falsely elevated
• Other work up contingent on presentation:
  • MRI spine: low threshold if any clinical evidence of cord compression
  • Plain films of suspected pathologic fractures
  • Infectious work up

Management

• Treat pain
  • Consider referring to palliative care if feasible (or suggesting consult to patient/inpatient team)
• Manage other complications:
  • If febrile, get cultures, start broad-spectrum antibiotics
  • Splint fractures and/or consult ortho as appropriate
  • See Hypercalcemia, Hypercalcemia of malignancy
    • Prednisone 60mg PO daily can be helpful in addition to standard hypercalcemia treatments
  • See Cord compression, Malignant spinal cord compression, Epidural compression syndromes
  • See Renal failure
  • See Anemia
    • If patient is eligible for transplant and indication equivocal, may want to avoid transfusion and/or consult oncology