Amyloid arthropathy is the extracellular deposition of the fibrous protein amyloid within the skeletal system. It is a skeletal manifestation of amyloidosis and may involve either the axial skeleton (especially the cervical spine) or the appendicular skeleton.
Shoulder pain and carpal tunnel syndrome are the most common clinical manifestations. Symptoms are commonly bilateral.
Patients can also develop osteolytic bone lesions (amyloidomas).
Amyloid arthropathy results from the deposition of β2-microglobulin, particularly in renal failure patients undergoing long-term haemodialysis.
Pathogenesis is probably multifactorial and relates to the duration of renal failure, patient's age, age at commencing haemodialysis and duration of haemodialysis 2.
Amyloid protein is not filtered by standard dialysis membranes and tends to accumulate in the musculoskeletal system 1.
Features of amyloid arthropathy are those of an erosive and destructive osteoarthropathy, involving most commonly the hips, shoulders and carpal bones. Distribution is frequently bilateral.
In the large joints, amyloid arthropathy resembles inflammatory arthritis with:
- juxta-articular soft tissue swelling(s)
- mild periarticular osteoporosis
- subchondral cystic lesions, usually with well-defined sclerotic margins
- joint space is usually normal in width until late in the course of the disease
The MR imaging appearance of amyloid infiltration within or around the joint consists of extensive deposition of an abnormal soft tissue that has:
- T1: low or intermediate signal intensity
- T2: low to intermediate signal intensity
This abnormal material covers the synovial membrane, fills subchondral defects, and extends to periarticular soft tissue. Joint effusion is usually present.
Differential for multiple lytic bone lesions include:
- multiple myeloma
However, the peri-articular distribution is a distinguishing feature.
- renal failure patients undergoing long-term haemodialysis
- periarticular soft tissue swelling, joint effusion, and large subchondral erosions ("cysts")
- deposition of an abnormal soft tissue with low signal on all MRI sequences
- pathologic fracture may happen
- 1. Llauger J, Palmer J, Rosón N et-al. Nonseptic monoarthritis: imaging features with clinical and histopathologic correlation. Radiographics. 2000;20 Spec No : S263-78. Radiographics (full text) - Pubmed citation
- 2. Kiss E, Keusch G, Zanetti M et-al. Dialysis-related amyloidosis revisited. AJR Am J Roentgenol. 2005;185 (6): 1460-7. doi:10.2214/AJR.04.1309 - Pubmed citation
- 3. Cobby MJ, Adler RS, Swartz R et-al. Dialysis-related amyloid arthropathy: MR findings in four patients. AJR Am J Roentgenol. 1991;157 (5): 1023-7. AJR Am J Roentgenol (abstract) - Pubmed citation
- 4. Hwang SS, Park YH, Kim JY et-al. Primary amyloidoma of the cervical spine. AJNR Am J Neuroradiol. 2000;21 (3): 601-3. AJNR Am J Neuroradiol (full text) - Pubmed citation
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