Episode 5: Board Review Bonus: Renal Amyloidosis

In this "Board Review Bonus" (BRB) episode, hosts Dr. Kenar Jhaveri and Dr. Koyal Jain provide a comprehensive clinical overview of amyloidosis—a complex and often enigmatic disease with significant renal implications. From the initial "mushy, smudgy" appearance on light microscopy to the precise measurements of electron microscopy, our hosts break down the essential knowledge required for both board preparation and clinical practice.

The discussion moves beyond the common AL and AA variants to explore rare types like LECT2 and the hereditary forms. Dr. Jain and Dr. Jhaveri emphasize that "the tissue is the issue," highlighting the diagnostic necessity of biopsying the affected organ and the critical role of mass spectrometry in directing therapy.

Key Topics Covered:

• Classification of Amyloidosis: A detailed look at AL, AA, LECT2, and the hereditary variants including ATTR, fibrinogen A alpha-chain, and Apolipoprotein.
• The Diagnostic Workup: Understanding the utility of Congo red staining, the significance of birefringence, and the institutional variability of fat pad biopsies.
• Electron Microscopy (EM) Pearls: A guide to differentiating amyloid fibrils from mimics such as fibrillary GN, immunotactoid GN, and cryoglobulinemia based on diameter and arrangement.
• Clinical Management: Navigating the multidisciplinary approach between nephrology, hematology, and cardiology, including the nuances of RAAS inhibition and diuretic therapy in proteinuric patients.
• Transplantation Outcomes: Evaluating recurrence rates and survival benefits for different amyloid types post-kidney transplant.

Recommended Resources and Literature:

• • Visual Aid: Concept Map: Causes of Renal Amyloidosis – A comprehensive resource for classifying amyloid variants and their underlying triggers (via NephronPower).
  • Dandona P, et al. The amyloidoses: clinical features, diagnosis and treatment. Methodist Debakey Cardiovasc J. 2012 Jul-Sep;8(3):3-7. PMC3487569
  • Panichella G, et al. Heart Failure Management in Cardiac Amyloidosis: Towards a Paradigm Shift. Heart Fail Rev. 2024. PMC12308146
  • Moreno-Martínez P, et al. LECT2-associated renal amyloidosis (ALECT2): A case report. Nefrologia. 2018 Jan-Feb;38(1):97-99. PMID: 29254900
  • Benson MD, et al. Hereditary renal amyloidosis associated with a mutant fibrinogen alpha-chain. Nat Genet. 1993 Mar;3(3):252-5. PMID: 8097946