Systemic AA amyloidosis: epidemiology, diagnosis, and management

Abstract

The term “amyloidosis” encompasses the heterogeneous group of diseases caused by the extracellular deposition of autologous fibrillar proteins. The global incidence of amyloidosis is estimated at five to nine cases per million patient-years. While amyloid light-chain (AL) amyloidosis is more frequent in developed countries, amyloid A (AA) amyloidosis is more common in some European regions and in developing countries. The spectrum of AA amyloidosis has changed in recent decades owing to: an increase in the median age at diagnosis; a percent increase in the frequency of primary AL amyloidosis with respect to the AA type; and a substantial change in the epidemiology of the underlying diseases. Diagnosis of amyloidosis is based on clinical organ involvement and histological evidence of amyloid deposits. Among the many tinctorial characteristics of amyloid deposits, avidity for Congo red and metachromatic birefringence under unidirectional polarized light remain the gold standard. Once the initial diagnosis has been made, the amyloid subtype must be identified and systemic organ involvement evaluated. In this sense, the 123I-labeled serum amyloid P component scintigraphy is a safe and noninvasive technique that has revolutionized the diagnosis and monitoring of treatment in systemic amyloidosis. It can successfully identify anatomical patterns of amyloid deposition throughout the body and enables not only an initial estimation of prognosis, but also the monitoring of the course of the disease and the response to treatment. Given the etiologic diversity of AA amyloidosis, common therapeutic strategies are scarce. All treatment options should be based upon a greater control of the underlying disease, adequate organ support, and treatment of symptoms. Nevertheless, novel therapeutic strategies targeting the formation of amyloid fibrils and amyloid deposition may generate new expectations for patients with AA amyloidosis.

Epidemiology of AL amyloidosis: a real-world study using US claims data

“…4 Similarly, Real de Asúa et al reported a mean age of 66 years among 24 AL amyloidosis patients admitted to a hospital in Spain between 2000 and 2010. 23 In another study with 232 AL amyloidosis patients with cardiac dysfunction, median age at presentation was 59 years. 24 In this study, we observed an increase in AL amyloidosis prevalence over a 9-year period (2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015), coupled with stable incidence.…”

Untitled

“…SAP binds to all types of amyloid precursors in a calcium-dependent manner, stabilizing their tertiary structure. [14] SAP is a physiological component of the glomerular basal membrane in kidneys, the basal membranes in skin, liver, lungs, blood vessels; it is a component of microfibrils lining the elastic membranes. These microfibrils structurally resemble amyloid fibrils.…”

Renal Amyloidosis Secondary to Undifferentiated Connective Tissue Disorders: A Rare Case Report From India.

“…24 hours urine protein may guide in diagnosis and the need for renal biopsy when diagnostic ambivalence arises due to equivocal vasculitic profile laboratory tests. [11] Conclusion:-Undifferentiated connective tissue disease may lead to renal involvement in the form of renal amyloidosis. Early diagnosis helps in reducing mortality.…”