Given the presentation of heart failure with multi-organ involvement, several important differential diagnoses should be considered:
- Other infiltrative cardiomyopathies
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Sarcoidosis - Can present with heart failure, conduction abnormalities, and multi-system involvement but typically shows high-grade heart block and ventricular arrhythmias
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Hemochromatosis - May present with heart failure and hepatic involvement, but typically presents with diabetes and skin pigmentation changes
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Glycogen storage diseases - Usually present earlier in life with more pronounced myopathy
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Other causes of restrictive cardiomyopathy
- Endomyocardial fibrosis - More common in tropical regions
- Radiation-induced cardiomyopathy - Requires history of chest radiation
- Hypereosinophilic syndrome - Associated with eosinophilia and systemic manifestations
- Hypertrophic cardiomyopathy
- May mimic amyloidosis with wall thickening and heart failure
- Usually shows asymmetric septal hypertrophy and systolic anterior motion of mitral valve
- Typically has high voltage (not low voltage) ECG findings
- Systemic autoimmune conditions
- Systemic lupus erythematosus - Can present with multi- organ involvement including heart, kidneys
- Systemic sclerosis - May cause cardiomyopathy and renal disease
- Polymyositis/dermatomyositis - Associated with cardiac involvement and myopathy
- Multiple myeloma with end-organ damage
- Can present with heart failure, renal failure, and paraproteinemia
- Typically shows more pronounced bone marrow plasma cell infiltration
- Often has hypercalcemia and lytic bone lesions
- Fabry disease
- X-linked lysosomal storage disorder that can present with LVH, proteinuria, and neuropathy
- Often has angiokeratomas and distinctive corneal findings
The combination of restrictive cardiomyopathy with specific ECG findings (low voltage despite LVH), multiorganic involvement, and characteristic physical findings (macroglossia, periorbital purpura) strongly favored amyloidosis over these alternatives.
