AA amyloidosis can occur at any age. The primary clinical manifestation is proteinuria and/or renal insufficiency. A study from Finland found AA amyloidosis to be the most common cause of nephrotic syndrome in patients with rheumatoid arthritis. Hepatomegaly, splenomegaly, and autonomic neuropathy frequently occur as the disease progresses; cardiomyopathy occurs rarely. With chronic inflammatory diseases, amyloid progression is slow and survival is often more than 10 years, particularly with treatment for end stage renal disease. In contrast, untreated infections such as osteomyelitis, tuberculosis, or leprosy can produce a more rapidly progressive amyloid syndrome, which will remit with effective medical or surgical treatment of the infection.
The major therapy in AA amyloidosis is treatment of the underlying inflammatory or infectious disease. Treatment which suppresses or eliminates the inflammation or infection also decreases the serum amyloid A (SAA) protein. For familial Mediterranean fever, colchicine in a dose of 1.2-1.8 mg/day is the appropriate treatment. Colchicine has not been helpful for AA amyloidosis of other causes, or for other amyloidoses. A multicenter trial using a new anti-amyloid drug, FibrillexTM, is underway for the treatment of AA amyloidosis. FibrillexTM has been designed to interfere with the interaction of AA amyloid protein with glycosaminoglycans in tissues and thus prevent fibril formation and deposition.