From the Guidelines
Polyuria in AL amyloidosis is a significant indicator of kidney involvement, suggesting renal amyloid deposition that impairs the kidneys' ability to concentrate urine, leading to excessive urine production. In AL amyloidosis, the deposition of abnormal protein fibrils in kidney tissues, particularly in the glomeruli, causes damage to nephrons and disrupts normal kidney function, resulting in nephrotic syndrome with symptoms including polyuria, often accompanied by proteinuria, edema, and progressive decline in kidney function 1. The increased urine output occurs because the damaged kidneys cannot properly reabsorb water and electrolytes, resulting in dilute urine and increased urinary frequency. Kidney involvement is common in AL amyloidosis, affecting approximately 70% of patients, and may progress to end-stage renal disease if left untreated 1. Management focuses on treating the underlying plasma cell dyscrasia with chemotherapy or autologous stem cell transplantation to stop the production of amyloidogenic light chains, while providing supportive care for kidney function. Some key aspects of management include:
- Monitoring for dehydration, electrolyte imbalances, and worsening kidney function through regular blood tests and urinalysis.
- Involvement of nephrologists in the multidisciplinary care for managing nephrotic syndrome, cardiorenal syndrome, metabolic complications of chronic kidney disease, and nephrotoxic effects of treatments for amyloidosis 1.
- Consideration for kidney replacement therapy, including hemodialysis, peritoneal dialysis, or kidney transplantation, for patients who progress to end-stage kidney disease 1.
From the Research
Definition of Polyuria
- Polyuria refers to the production of an abnormally large volume of urine, typically more than 3 liters per day [@\1@, @\2@, @\3@, @\4@, @\5@].
Polyuria in AL Amyloidosis
- In the context of AL amyloidosis, polyuria can be a symptom of renal involvement, which is a common feature of the disease [@\2@, @\3@].
- Renal amyloidosis can cause damage to the kidneys, leading to a range of symptoms including proteinuria, hematuria, and polyuria [@\3@].
- The presence of polyuria in AL amyloidosis patients may indicate renal dysfunction and require close monitoring and management [@\2@, @\4@, @\5@].
Renal Involvement in AL Amyloidosis
- Renal involvement is a common feature of AL amyloidosis, with approximately 50-60% of patients experiencing renal symptoms [@\1@, @\2@].
- The renal staging system, which takes into account eGFR and proteinuria, can be used to predict renal outcomes and guide treatment decisions [@\2@].
- Treatment of AL amyloidosis with bortezomib, lenalidomide, and dexamethasone can help improve renal function and reduce proteinuria [@\1@, @\2@, @\4@, @\5@].
Management of Polyuria in AL Amyloidosis
- Management of polyuria in AL amyloidosis patients typically involves a combination of supportive care and treatment of the underlying disease [@\3@, @\4@, @\5@].
- Supportive care may include fluid replacement, electrolyte management, and monitoring of renal function [@\2@, @\3@].
- Treatment of the underlying disease with bortezomib, lenalidomide, and dexamethasone can help improve renal function and reduce polyuria [@\1@, @\2@, @\4@, @\5@].