Amyloidosis

There are four main categories for systemic amyloidosis:

AL (light chain) amyloidosis—associated with a plasma cell dyscrasia or myeloma.This is the most common and lethal form of amyloidosis and requires urgent diagnosis and treatment. Chemotherapy—typically cyclophosphamide and dexamethasone with bortezomib or thalidomide—suppresses production of the amyloidogenic monoclonal serum free light chains. The aim of treatment is to suppress the clone as rapidly and deeply as possible while limiting toxic effects. A 90% or greater suppression of the monoclonal serum free light chain component can result in substantial improvements in organ function and overall survival.
AA (serum amyloid A protein) amyloidosis—associated with chronic inflammation; for example, rheumatoid arthritis, Crohn’s disease, bronchiectasis and inherited fever syndromes such as familial Mediterranean fever.The precursor protein for this amyloid type is serum amyloid A protein, an inflammatory protein similar to C-reactive protein. Chronic raised concentrations of serum amyloid A over many years can result in this type of amyloidosis, typically involving the kidneys, leading to substantial renal impairment or failure with nephrotic syndrome. Treatment is suppression of the underlying cause of inflammation, such as with anti-tumour necrosis factor drugs in rheumatoid arthritis. With adequate control of inflammation (serum amyloid A concentrations persistently <10mg/L), prognosis can be excellent.
Hereditary amyloidosis—there are several types of hereditary amyloid diseases, and these can mimic systemic AL amyloidosis. A family history can often be absent, and chemotherapy is ineffective. Screening for amyloidogenic genetic mutations, where relevant, is part of the routine assessment at the National Amyloidosis Centre, after patient counselling and consent. Solid organ transplantation can be used in some cases to replace failed organ function.
Senile systemic amyloidosis—amyloid fibrils from misfolded wild-type (“normal”) transthyretin protein deposit in the carpal tunnels and cardiac tissue, leading to a restrictive cardiomyopathy. This condition is most commonly seen in older, white men. Treatment is with diuretics and standard anti-failure medication.

Amyloidosis (2011)