Features of dialysis related amyloidosis
Dialysis-associated amyloidosis is caused by β 2 – microglobulin amyloid deposits. β 2 -microglobulin is the invariant chain of the major histocompatibility complex class I molecule. Serum β 2 -microglobulin levels are elevated 50 to 100 times normal in patients on long-term dialysis. However, high levels alone do not predict the development of amyloid. Generally, patients with amyloidosis will have been on hemodialysis for at least 5 years. Up to 80% of patients who undergo dialysis for >15 years will have evidence of amyloidosis. These patients present mainly with osteoarticular complaints. CTS is the first and most common clinical presentation. Chronic arthralgias, especially of the shoulders, may also occur. Patients can have the shoulder pad sign with inability to raise arms over their head. Persistent noninflammatory joint effusions in large joints can occur in up to 50% of patients. β 2 -microglobulin amyloid deposits can be found in the synovial fluid sediment with Congo red staining. A spondyloarthropathy with intervertebral disc destruction (mimics infection) and paravertebral erosions from amyloid deposits have been described. Cystic bone changes (carpals and other bones) can occur due to advanced glycation end products stimulating osteoclasts resulting in cyst formation. Rarely, other areas (skin, gastrointestinal tract, heart) are involved. The treatment is renal transplantation.
