Which Statement About Amyloidosis is Correct?
The correct answer is (d): amyloidosis can be a complication of chronic hemodialysis, and (a) is also correct as cardiac amyloidosis frequently manifests with arrhythmias.
Analysis of Each Statement
Statement A: Cardiac Amyloidosis Manifests with Arrhythmias - TRUE
Arrhythmias are a well-recognized manifestation of cardiac amyloidosis and require specific management considerations. 1
- Atrial fibrillation is particularly common in cardiac amyloidosis, even in the setting of sinus rhythm, due to amyloid infiltration causing atrial mechanical "standstill" 1
- The American Heart Association guidelines emphasize that management of arrhythmias is a key component of supportive treatment in cardiac amyloidosis 1
- Conduction system problems frequently occur alongside arrhythmias, requiring careful monitoring 1
Statement B: Main Finding of Renal Involvement is Microscopic Hematuria - FALSE
The primary manifestation of renal amyloidosis is heavy proteinuria and nephrotic syndrome, not microscopic hematuria. 2
- Renal amyloidosis typically presents with heavy proteinuria, nephrotic syndrome, and progression to end-stage renal failure 2
- Amyloid deposits occur within glomeruli and/or the interstitium, causing proteinuria rather than hematuria as the dominant feature 2
Statement C: Subcutaneous Fat Biopsy is the Safest Diagnostic Method - TRUE (with important caveats)
Abdominal fat pad aspiration is indeed a safe and commonly used diagnostic method, but it has significant limitations. 1
- Fat pad biopsy is explicitly mentioned as a safe alternative to endomyocardial biopsy for diagnosis 1
- However, a critical pitfall is that fat pad biopsy has only 84% sensitivity for AL cardiac amyloidosis 3
- A negative fat pad biopsy is NOT sufficient to exclude cardiac amyloidosis 1
- When fat pad biopsy is negative but clinical suspicion remains high, endomyocardial biopsy or other tissue sampling is required 1
- Other accessible biopsy sites include bone marrow, gingiva, rectum, and minor salivary glands 1
Statement D: Can Be a Complication of Chronic Hemodialysis - TRUE
Dialysis-related amyloidosis (β2-microglobulin amyloidosis) is a recognized complication of long-term chronic hemodialysis. 1
- AA amyloidosis, which can occur in the context of chronic inflammatory conditions, is mentioned in the guidelines 1
- While not extensively detailed in the provided evidence, dialysis-related amyloidosis is a well-established entity in patients on long-term hemodialysis
Statement E: Treatment of Choice is Dapsone - FALSE
Dapsone is NOT the treatment of choice for amyloidosis; treatment depends on the amyloid type. 1, 3
- For AL amyloidosis, daratumumab-CyBorD is the preferred first-line option for both transplant-eligible and ineligible patients 3
- The goal is to eradicate pathological plasma cells and remove affected light chains from circulation 3
- Treatment is largely supportive for cardiac manifestations, including management of heart failure, arrhythmias, and conduction problems 1
- Disease-directed therapy aims to eliminate plasma cell dyscrasia in AL amyloidosis, not dapsone 1
Critical Diagnostic Considerations
Accurate amyloid typing is mandatory and cannot be bypassed:
- Mass spectrometry is the gold standard for typing with 88% sensitivity and 96% specificity 3, 4
- Congo red staining showing apple-green birefringence under polarized light is pathognomonic and essential for diagnosis 1, 4
- Immunohistochemistry should be performed to identify the specific amyloid protein type 1
Common pitfall to avoid: Do not assume the amyloid type based solely on clinical presentation or the presence of a monoclonal protein—tissue diagnosis with proper typing is essential 3, 5