Uncovering the knowledge about systemic amyloidosis relevant to the rheumatologists.

Amyloidosis is a localized or systemic disease caused by deposition of proteins in the extracellular space of various organs and tissues. As part of the disease, proteins that were originally soluble misfold and acquire a fibrillar conformation that renders them insoluble and resistant to proteolysis. Systemic amyloidosis is a rare, often underdiagnosed condition. In recent years, the incidence of newly diagnosed cases of amyloidosis has been increasing in association with the aging of the population and greater access to diagnostic tests. From a clinical perspective, systemic amyloidosis is frequently associated with involvement of the kidneys (causing nephrotic syndrome), heart (cardiac failure and arrhythmia), and peripheral nervous system (sensorimotor polyneuropathy and autonomic dysfunction). This condition is important to the rheumatologist for several reasons, such as its systemic involvement that mimics autoimmune rheumatic diseases, its musculoskeletal manifestations, which when recognized can allow the diagnosis of amyloidosis, and also because reactive or secondary AA amyloidosis is a complication of rheumatic inflammatory diseases. The treatment of amyloidosis depends on the type of amyloid protein involved. Early recognition of this rare disease is fundamental for improved clinical outcomes.