- Renal amyloidosis refers to the morphological and clinical consequences of amyloid deposition in the kidneys. Renal amyloidosis usually occurs in the context of primary or secondary amyloidosis. Consequently, it may manifest in patients with multiple myeloma or with chronic inflammatory conditions such as rheumatoid arthritis. The kidney is usually the first organ where amyloid deposition is observed in these diseases.
- Amyloid proteins primarily deposit in the glomeruli although minor deposition can be seen throughout the renal parenchyma. Glomerular deposition causes expansion of the mesangium and thickening of the glomerular basement membrane. With continuing disease, the glomerular capillaries narrow and eventually become obliterated.
- Amyloid deposition in the glomeruli reduces selectivity of glomerular filtration and thus causes nephrotic syndrome characterized by proteinuria, hypoalbuminemia, generalized edema, and hyperlipidemia.