 Systemic amyloidosis is a rare condition caused by the accumulation of misfolded proteins in the body's tissues and organs. This can lead to organ damage and eventually death if left untreated. Amyloidosis is often seen in people who have used heroin for many years and has been linked to other conditions such as hepatitis C. This article was authored by Chad Cooper, Jorge E. Bilbao, Sarmad said and others.