How to manage renal amyloidosis secondary to bronchiectasis in the absence of light chain abnormality?

From the Guidelines

Management of renal amyloidosis secondary to bronchiectasis without light chain abnormality requires a dual approach targeting both the underlying bronchiectasis and the renal manifestations, with a focus on controlling the inflammatory process and preventing further amyloid deposition. To achieve this, aggressively treat the bronchiectasis with appropriate antibiotics for acute exacerbations, regular airway clearance techniques, and maintenance antibiotics if indicated, as suggested by the British Thoracic Society guideline for bronchiectasis in adults 1. Consider macrolides like azithromycin 500mg three times weekly for their anti-inflammatory properties. For the renal amyloidosis, implement strict blood pressure control (target <130/80 mmHg) using ACE inhibitors or ARBs as first-line agents, which help reduce proteinuria and slow progression of renal damage, as recommended for patients with chronic kidney disease 1. Monitor renal function regularly with serum creatinine, eGFR, and urinary protein measurements every 3-6 months. Some key points to consider in management include:

• Dietary sodium restriction (<2g/day) and protein moderation (0.8g/kg/day) are important to reduce the strain on the kidneys.
• Diuretics may be needed for edema management.
• Controlling the inflammatory bronchiectasis is crucial to prevent further amyloid deposition, as this type of amyloidosis (AA amyloidosis) results from chronic inflammation causing elevated serum amyloid A protein deposition in kidneys.
• In advanced cases, dialysis or kidney transplantation may be necessary, but addressing the underlying bronchiectasis remains essential even after transplantation to prevent recurrence, with recent experience of renal transplantation in selected patients showing encouraging outcomes 1.

From the Research

Management of Renal Amyloidosis Secondary to Bronchiectasis

In the absence of light chain abnormality, managing renal amyloidosis secondary to bronchiectasis involves several key considerations:

• The condition is characterized by the deposition of amyloid A (AA) in multiple organs and tissues, including the kidneys, leading to end-stage renal disease (ESRD) 2.
• Treatment of the underlying condition, such as bronchiectasis, is crucial to prevent further amyloid deposition and progression of renal disease 3, 4.
• Colchicine therapy has been shown to improve proteinuria, serum albumin levels, and edema in patients with AA amyloidosis 3.
• In some cases, renal transplantation may be considered, especially if the patient has end-stage renal disease and is on dialysis 3, 5, 6.
• Supportive management, including dialysis, may be necessary for patients with advanced renal disease 6.

Clinical Considerations

• Patients with bronchiectasis-related amyloidosis often have a long history of chronic respiratory infections and may develop ESRD over time 2.
• The clinical course of patients with cystic bronchiectasis may be worse than those with other types of bronchiectasis due to complicating pulmonary infections 2.
• Renal biopsy is essential for diagnosing renal amyloidosis, and immunohistochemistry can help identify the type of amyloid protein deposited 5, 6.
• Regular follow-up and monitoring of renal function, proteinuria, and serum albumin levels are crucial for managing patients with renal amyloidosis secondary to bronchiectasis 3, 5.