Presentations of amyloidosis that mimic other rheumatic diseases
Vascular involvement by amyloid can lead to claudication of the extremities and jaw as seen in temporal arteritis.
Amyloid arthropathy can mimic seronegative RA.
Clues are the lack of inflammation and frequent hip and shoulder involvement with periarticular amyloid infiltration, which leads to enlargement of the pelvic or shoulder girdle (shoulder pad sign).
Synovial fluid analysis can be helpful in detecting amyloid deposits. Infiltration of amyloid into muscle may lead to weakness or pain, simulating polymyositis.
Enlargement of involved muscles (pseudohypertrophy) can be striking and may not be associated with other symptoms.
