Amyloid Arthropathies and other Musculoskeletal Problems in Multiple Myeloma

Patients with multiple myeloma may consult physicians because of bone pain or compression fractures but may also develop a variety of other musculoskeletal problems. Lytic bone lesions due to myeloma may develop pathologic fractures. Destructive lesions can cause nerve root compression. Myeloma can cause hyperuricemia and gout. Amyloidosis can also complicate myeloma and can produce extreme amounts of joint swelling with tissue coated with amyloid and masses of amorphous amyloid distending the joint space. Such effusions are cloudy due to the amyloid usually without an inflammatory cell response. Some myeloma patients have developed unusual finger contracture. Some of these are due to amyloidosis but other factors may also be involved. Paraneoplastic urticarial vasculitis or other arteritis has been reported with multiple myeloma as well as with other malignancies. An especially interesting group or myeloma patients are those with immunoglobulin deposits in vessels producing large or small vessel vasculitis. Others get actual immunoglobulin crystal deposition in vessels producing a vasculopathy mimicking polyarteritis. Some of these patients also get an erosive arthritis due to cryrocrystalglobulins. Therapy to lower monoclinal globulins with plasma exchange or chemotherapy may help.